Rust Removal from Precision Cast Iron Surfaces in 2020: techniques and when to stop

[Devin Brenan]

Hello all.

I'm on a (maybe brief, maybe permanent) machinery restoration kick, and I like to overthink everything before I do it. I'll own it.

Bought a (probably 1950's) E-16 Powermatic planer in running condition that I want to take apart and restore/reassemble for fun. Light to medium rust removal will be part of process for sure, and I've been trying to sift out the facts from the variety of advice out there, often contradictory. Say we're talking about removing surface rust from cast iron tables or mating surfaces like ways...so far I've read things like:

** "if you remove rust from a precision surface, you no longer have a precision surface, changes the dimension, changes the surface"...yes this was from a machinist site probably dealing with ten thousandths.

or

** "surface rust is NOTHING. My contractor saw gets left out in the rain all the damn time. I just take an abrasive pad and rotary sander to it and it's as good as new. I can still see the original grind marks in the cast iron. No problem"

and

** "Dimensionally, the volume/thickness of a rust layer is about 100 times thicker than the Iron layer needed to create it. So removing 100 thou of rust would only remove 1 thou of your original iron" <--that would make some sense to me...don't know if it's true or not though or if the 100 to 1 thing is true

and

** "Tolerance goals for precision cast iron woodworking surfaces tend to be in the single digit thousandths...like +/- 3 thou over a large jointer table. So surface rust can usually be removed without affecting the original tolerances that much or sometimes at all" <--would like that to be true


So can you all weigh-in on your thoughts on any of the above statements...or more preferably...your experiences? Would love to hear 'em.

And what're your favorite abrasive techniques and products (steel wool or scotch brite and what grit level, rotary or rotary/oscll. sander, etc.) and chemical products (vinegar/acetic acid, brand name products like evaporust, muriatic acid, citric acid, diluted hydrochloric acid...etc) that you've tried and like?



And now it's time to go play in the shop. Look forward to your replies and hope you all have a good one this weekend.

-Devin

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[Erik Loza]

There's rust and then there's rust. I've never had any issues as far as what you are worried about, when removing light surface with the usual means (R/O sander with a red or grey scotchbrite). If the surface is pitted, that could be a different story. What does the planer table actually look like?

Erik

[Eric Arnsdorff]

My favorite is phosphoric acid (naval jelly as the product in a liquid gel form) with a brillo pad scrub. Following that cleaning with a brillo and some WD-40 has made pretty quick work of fairly rusted surfaces.
I have no tools capable of detecting 2-3 thousandths runout over the length of my jointer table or table saw (or even my band saw or drill press table for that matter).
I've cleaned up a couple of cast iron tables that were in rusty condition but not extreme long term rust. I do have height gages that claim accuracy to half a thousandth (I haven't verified my best one on a calibrated block in quite a while though). I could see no localized variation of even a thousandth of an inch after cleaning them. I don't know about the full table runout. All of my cast iron tables are at least as good and likely better than any of my straight edges that are long enough to span it.
My take on it is rust removal of "typical" rust doesn't impact woodworking surfaces enough to matter. Extreme rust with large pitted areas could but I think it would have to be bad enough that it would already be obvious to you.

[Timothy Orr]

Here’s another way to think about it. The rusted surface certainly isn’t as precision as it was pre-rust, and it may not even be functional if moving parts are involved. So you sort of have no choice but to remove the rust.

For the tolerances in woodworking, any of the typical methods are going to give you a surface that is as precise and as function at the original. Naval jelly, scotch brite, evapo rust, electrolysis etc may technically remove surface material but not in measurable amounts that would affect a wood working tool. If you are talking about the ways on a engine lathe where a couple of ten-thousandths would impact accuracy of the tool that is a different story.

I’m talking about surface rust, now if you have actual pitting enough then you still to remove the rust then be thinking about how to repair the surface with fillers, re-machining etc.

My 2 cents.

Torr

[Bill Dufour]

Electrolytic or EDTA are the easiest and reasonably fast. Do not use stainless with electrolytic just plain iron or steel. Stainless can make some bad stuff with chrome compounds in the waste.
Bil lD

[Jim Matthews]

If you find the finished product (dimensioned boards) out if acceptable tolerances, a sled could be constructed to satisfy your requirements.

My SWAG is that there will be more error induced by cutter runout, uneven roller pressure or blade alignment.

Polish it until it shines!

[Richard Coers]

I take off any heavier rust with a single edge razor blade scraper. Then buffing with maroon Scotchbrite. I never use sandpaper since I don't want to remove metal.

[Patrick Kane]

Photos would help. Like everyone else, I’d remove the rust and then see what you have. The table might be dished in the middle from 50,000 sandy board feet. In that case, the rust doesn’t matter and you need to ace the table ground/planed.

I usually take off the heavy stuff with a brass brush mounted in a drill. A grinder would be even better. Once the majority of the surface rust is gone then I switch to an RO with a scotchbrite pad. I think you can do some damage with an RO and 80-100 grit paper, but I don’t think 220-320 would remove a meaningful amount of metal. I’ve never taken a top from rusty to shiny new cast iron. My ‘restored’ tops always have the dull patina of stained cast iron. I’d like to polish the T17’s top to a mirror, so I’m open to suggestions from folks. I might try the scotchbrite pad on the sander with some bar keepers friend or similar.

[Matt Day]

Razor blade, scotch brite on a cup wheel of an angle grinder. Don’t overthink it.

[Mark e Kessler]

Barkeepers friend and scotchbrite

[Mike Wilkins]

Cleaned up the column on an old drill press with a Scotchbrite pad and WD-40 with no problem. Same with some light rust on a table top of a Unisaw I restored.
There are other commercial rust removal products out there for the heavy stuff. Naval Jelly is good but leaves a funny looking protective residue which I don't like.
The least invasive the better; hand power only for the light stuff. Wire wheels in a grinder for the heavy stuff.

[George Makra]

Soda blasting does not harm the base material at all. It removes rust and other crud and leaves a light dust on the surface.

[David Kenagy]

...if you have actual pitting...be thinking about...re-machining...

My reconditioned 8” jointer has pitting of the table surface, as well as dings in the tapered metal pieces at the opening. They are a lighter shade of gray than the tables, but don’t seem as soft as aluminum. They’re no longer available, but a shop could surely fabricate those, couldn’t they?

How do you find somebody who can do that work, and do it well? When I’ve called machine shops, (a hobbyist, not a pro) my amateur way of describing what I need either confuses the guy, or convinces him that he’d be wasting his time.

How do you choose a shop, then describe resurfacing a jointer surface? What’s a fair price?

[Tom Bender]

ROS with grit to match the work required. Better to get thru it in a few minutes than to go very slowly and spend a long time. The faster approach will encourage you to finish all the surface the same rather than focus on the bad spot.

[Ole Anderson]

You would have to do some serious rust/base metal removal to make a difference in flatness measurable by any normal tools in your shop. I doubt you would remove even a few thousandths unless you wanted to remove all traces of serious pitting..

[Michael Drew]

Barkeepers friend and scotchbrite

Now why didn't I think of that!

I use BKF routinely for my stainless cookware. Never thought to use it for my machinery......

[Mark e Kessler]

just be sure to not let it sit to long, it works well because of the Oxalic acid just don’t leave it on to long or it will discolor the cast iron (which you can remove by reapplying). I use a little bit of water with it and red scotchbrite then clean up all the residue with water and rags and have found orange cleaner/degreaser cleans it up well too.


Now why didn't I think of that!

I use BKF routinely for my stainless cookware. Never thought to use it for my machinery......

[Patrick Kane]

Yep, just found out how quickly it oxidizes cast iron to a weird green/yellow. I’d say less than 5 mins. I wasn’t sure if I was a dummy for using water as my lubricant. I don’t love the smell of solvents in an enclosed garage. Anyway, it did a bang up job with the scotchbrite pad, ROS, and the powder. I just wiped it clean with mineral spirits and a rag, but I think it will need polished again.

[Erik Loza]

Yep, just found out how quickly it oxidizes cast iron to a weird green/yellow. I’d say less than 5 mins. I wasn’t sure if I was a dummy for using water as my lubricant. I don’t love the smell of solvents in an enclosed garage. Anyway, it did a bang up job with the scotchbrite pad, ROS, and the powder. I just wiped it clean with mineral spirits and a rag, but I think it will need polished again.

I always use WD-40 as the cutting fluid when buffing the tables. Wipe off with mineral spirits, then wax immediately.

Erik

[lowell holmes]

These work for me.
https://www.google.com/search?sxsrf=ALeKk03wsjzK9K05XPh3a7IHe66wQeiswQ%3A 1600695006003&ei=3apoX8vkPMyEsAWY_b2QDQ&q=wire+wheel+brush+home+depot&oq=wire+wheel+brush&gs_lcp=CgZwc3ktYWIQARgBMgQIABBHMgQIABBHMgQIABBHMgQ IABBHMgQIABBHMgQIABBHMgQIABBHMgQIABBHSgUINxIBMUoFC CQSATFQAFgAYIHpAmgAcAJ4AIABAIgBAJIBAJgBAKoBB2d3cy1 3aXrIAQjAAQE&sclient=psy-ab

[Mike Stelts]

I also use wire brushes, like Lowell's Google link, wipe with mineral spirits, and wax. The wires aren't as hard as the tables, so only the rust is removed.

[Devin Brenan]

Thanks all for the great replies! Great info. Hope to have more time shortly to answer some replies individually, but here are a few pics of the table condition. Also notice the top of the ways are rusted a bit...bottoms are the same. For the table though, in a nutshell, looks like ?minor? pitting and a ~ 5 to 6 thou wallow in the center. Could easily get a 5 thou feeler gauge under the straightedge, 6 thou had some resistance, 7 nope. Powermatic's manuals for other/similar planers...say the 225 for instance...indicates that one should should set the knives to within 1 thou from end to end on the planer table. "Maximum deviation allowed for good planing is .001 (.025mm)." See 225 manual screenshot below. That'd be tough to do with a table off by 6 thou...yes it's a wallow and the ends of the table are probably at a similar height but this type of stuff irritates me...even if it might not visually impact a good portion of wood/projects that I'd build. The manual says it, and I want it. I'll clean it up as best I can with the advice you all have given, and then decide whether I want to have it reground or planed once I get it all apart.

Cheers,

Devin

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[Erik Loza]

Devin. I've seen a lot worse. If I were you, I would scotchbrite that table to give it some "grain", wax thoroughly with johnson's paste wax, then run some boards through it. See what it does before you make any decisions. Pulling the table and having it machined should be a last resort.

Erik

[Patrick Kane]

.006" would bug me, especially if i went through the hassle of repainting the machine, replacing other parts, and general cleanup. However, Erik is right, that level of dip really wont make a difference. That is a little less than 1/128", which is pretty slight if it transmits to the surface and thickness of a board. With that said, if you are already pulling the table, then i would be very hard pressed to not have the top reground. As an example, i havent dug into my Martin T17, but i know the bevel sprocket is missing a tooth. It doesnt affect the chain mechanism and beveling the blade, but its hard for me to leave that broken part in place knowing im going to spend 20-30 hours on this thing and another couple hundred bucks.

[Bill Dufour]

You really need to redefine precision. You are just talking the ground surfaces that the wood moves over. i thought you meant the sliding surfaces. I do not think I have ever heard of a wood machine having scraped in surfaces like many metal working machines will have. Any thing around 1/1000 is plenty good for wood working.
Bil lD.

[Devin Brenan]

My favorite is phosphoric acid (naval jelly as the product in a liquid gel form) with a brillo pad scrub. Following that cleaning with a brillo and some WD-40 has made pretty quick work of fairly rusted surfaces.
I have no tools capable of detecting 2-3 thousandths runout over the length of my jointer table or table saw (or even my band saw or drill press table for that matter).
I've cleaned up a couple of cast iron tables that were in rusty condition but not extreme long term rust. I do have height gages that claim accuracy to half a thousandth (I haven't verified my best one on a calibrated block in quite a while though). I could see no localized variation of even a thousandth of an inch after cleaning them. I don't know about the full table runout. All of my cast iron tables are at least as good and likely better than any of my straight edges that are long enough to span it.
My take on it is rust removal of "typical" rust doesn't impact woodworking surfaces enough to matter. Extreme rust with large pitted areas could but I think it would have to be bad enough that it would already be obvious to you.

Eric, thanks for the reply. Only recently heard about naval jelly. Glad to hear that works for you. And...

"All of my cast iron tables are at least as good and likely better than any of my straight edges that are long enough to span it." <--that's also a good point.

I do have a 48" Starrett straight edge (model 380-48) that claims an accuracy of +/-0.0002 per foot, or +/- 0.0008 over the whole thing with 1.6 thou worst case...but I have no way to measure that with a granite plate or anything. And the square I used to measure the table in a later response is .001 per inch advertised. Anyway, the more responses I get similar to yours, the less and less I'm caring about single-digit thousandths...I just thought why not aim for it if I can since they recommend setting your knives within 1 thou across the table anyway.

[Devin Brenan]

Here’s another way to think about it. The rusted surface certainly isn’t as precision as it was pre-rust, and it may not even be functional if moving parts are involved. So you sort of have no choice but to remove the rust.

For the tolerances in woodworking, any of the typical methods are going to give you a surface that is as precise and as function at the original. Naval jelly, scotch brite, evapo rust, electrolysis etc may technically remove surface material but not in measurable amounts that would affect a wood working tool. If you are talking about the ways on a engine lathe where a couple of ten-thousandths would impact accuracy of the tool that is a different story.

I’m talking about surface rust, now if you have actual pitting enough then you still to remove the rust then be thinking about how to repair the surface with fillers, re-machining etc.

My 2 cents.

Torr

Thanks for the reply...and yea point taken about the rust..it'll have to come off no matter what I suppose and then I can assess where the table is at. As of right now when I measure it with the tools I have, it's showing a ~ 6 thou wallow in the center of the table that'll probably be there-to-stay unless I have it resurfaced. I may decide to live with the wallow though, tbd.

[Devin Brenan]

Electrolytic or EDTA are the easiest and reasonably fast. Do not use stainless with electrolytic just plain iron or steel. Stainless can make some bad stuff with chrome compounds in the waste.
Bil lD

Thanks for the reply...I will google it. Don't think anyone else brought this method up. How or on what have you used it before?

[Devin Brenan]

If you find the finished product (dimensioned boards) out if acceptable tolerances, a sled could be constructed to satisfy your requirements.

My SWAG is that there will be more error induced by cutter runout, uneven roller pressure or blade alignment.

Polish it until it shines!

Another good point, I guess I'm just trying to control what I can. If I go to the trouble of taking it all apart, might as well try and make the bed all it can be. At any rate, as someone else already mentioned, I suppose the rust has to go no matter what so maybe I'll get aggressive with it :)

[Devin Brenan]

I take off any heavier rust with a single edge razor blade scraper. Then buffing with maroon Scotchbrite. I never use sandpaper since I don't want to remove metal.

Thank you. Yea the razor blade technique seems to be the most universally agreed-upon. Your Scotchbrite buffing is with an RO sander or buffer though right?

[Devin Brenan]

Razor blade, scotch brite on a cup wheel of an angle grinder. Don’t overthink it.

:) "Don't overthink it" <--story of my life.


Cup wheel of an angle grinder---assuming there's a hook-and-loop or similar way of attaching the pad? I have a dewalt buffer with a hook and loop wheel but it wouldn't be as fast.

[Devin Brenan]

Barkeepers friend and scotchbrite

That's a 1st for Barkeepers friend...at least that I've heard as a newbie to this. Thanks.

[Devin Brenan]

Cleaned up the column on an old drill press with a Scotchbrite pad and WD-40 with no problem. Same with some light rust on a table top of a Unisaw I restored.
There are other commercial rust removal products out there for the heavy stuff. Naval Jelly is good but leaves a funny looking protective residue which I don't like.
The least invasive the better; hand power only for the light stuff. Wire wheels in a grinder for the heavy stuff.

Nice, thank you. Do you just clean off the WD-40 with mineral spirits or similar when you're done? A few folks said they favor Naval Jelly, but I'll be on the lookout for residue if I go that route.

[Devin Brenan]

My reconditioned 8” jointer has pitting of the table surface, as well as dings in the tapered metal pieces at the opening. They are a lighter shade of gray than the tables, but don’t seem as soft as aluminum. They’re no longer available, but a shop could surely fabricate those, couldn’t they?

How do you find somebody who can do that work, and do it well? When I’ve called machine shops, (a hobbyist, not a pro) my amateur way of describing what I need either confuses the guy, or convinces him that he’d be wasting his time.

How do you choose a shop, then describe resurfacing a jointer surface? What’s a fair price?

I read an article or two about this over on the vintage machinery site. They have a wiki section. Look for sections 2.8 Jointers & Planers (Grinding Jointer Tables) and 2.11 Restoration Tips ( Flattening Cast Iron Surfaces)

[Devin Brenan]

Soda blasting does not harm the base material at all. It removes rust and other crud and leaves a light dust on the surface.

I'll have to look that up...is that just similar to sand blasting...same basic process but with a different media? Thanks for the reply.

[Devin Brenan]

ROS with grit to match the work required. Better to get thru it in a few minutes than to go very slowly and spend a long time. The faster approach will encourage you to finish all the surface the same rather than focus on the bad spot.

No fear :)

I think I'm going to try this on *something*..maybe not this planer bed this time around if I choose not to resurface it...but if I do choose to resurface it, think I'm gonna experiment first. And a 'throw caution to the wind' approach with a ROS is a popular vote.

[Devin Brenan]

You would have to do some serious rust/base metal removal to make a difference in flatness measurable by any normal tools in your shop. I doubt you would remove even a few thousandths unless you wanted to remove all traces of serious pitting..

You are in agreement with a LOT of others, and there must be a reason for that..probably truth. I'm still looking to verify that the volume/thickness of surface rust is 100 times thicker than the iron layer needed to create it. It would make a lot of sense base on everyone's experiences with maintaining acceptable flatness after abrasives.

[Devin Brenan]

These work for me.
https://www.google.com/search?sxsrf=ALeKk03wsjzK9K05XPh3a7IHe66wQeiswQ%3A 1600695006003&ei=3apoX8vkPMyEsAWY_b2QDQ&q=wire+wheel+brush+home+depot&oq=wire+wheel+brush&gs_lcp=CgZwc3ktYWIQARgBMgQIABBHMgQIABBHMgQIABBHMgQ IABBHMgQIABBHMgQIABBHMgQIABBHMgQIABBHSgUINxIBMUoFC CQSATFQAFgAYIHpAmgAcAJ4AIABAIgBAJIBAJgBAKoBB2d3cy1 3aXrIAQjAAQE&sclient=psy-ab

Thanks for the reply. These wire wheels would be a more aggressive approach, but hey if it works for you, it works. And I guess you could use softer-metal wheels if need be as well..doesn't have to be steel.

[Devin Brenan]

I also use wire brushes, like Lowell's Google link, wipe with mineral spirits, and wax. The wires aren't as hard as the tables, so only the rust is removed.

Mike thanks for the reply. Yea I thought about the wire-hardness as I was responding to Lowell's link; if you choose a softer metal that the table that should work. Sounds like you've done it before anyway, so another good way to go about it.

[Devin Brenan]

Devin. I've seen a lot worse. If I were you, I would scotchbrite that table to give it some "grain", wax thoroughly with johnson's paste wax, then run some boards through it. See what it does before you make any decisions. Pulling the table and having it machined should be a last resort.

Erik

Erik thanks for the reply (and the earlier replies too). I was planning on taking it all apart anyway and replacing the head (with byrd or hermance) but thought it'd be 'fun' (and maybe even good-enough at the end) to see what happens after cleaning the table up. Was just unsure how I wanted to go about it, so I thought I'd solicit some opinions here. A lot of great advice, and it seems there are many ways to go about this and get good results. I'll just have to pick one to try first for the bed. Think I'm gonna go the Evaporust route for all the small parts. I will post more pics once I clean up the bed as best I can, and then I'll decide if I'm gonna have the bed resurfaced. Figure I could probably find a machine shop in the LA area that will do it. Would like to plane it, old-school style, if I go that route.

[Devin Brenan]

.006" would bug me, especially if i went through the hassle of repainting the machine, replacing other parts, and general cleanup. However, Erik is right, that level of dip really wont make a difference. That is a little less than 1/128", which is pretty slight if it transmits to the surface and thickness of a board. With that said, if you are already pulling the table, then i would be very hard pressed to not have the top reground. As an example, i havent dug into my Martin T17, but i know the bevel sprocket is missing a tooth. It doesnt affect the chain mechanism and beveling the blade, but its hard for me to leave that broken part in place knowing im going to spend 20-30 hours on this thing and another couple hundred bucks.

Bugs me too, and I only sorta know what I'm doing off advice from others and assuming things. No restoration experience.

Yea that missing tooth on the sprocket would keep me up at night :)...well maybe just irk me.

As far as the planer bed, I'm the type of person where if I see that same wallow transferred to my freshly-planed boards, it's gonna be unsat...especially like you said if I've already taken the whole thing apart.

Thanks for the replies.

[Devin Brenan]

You really need to redefine precision. You are just talking the ground surfaces that the wood moves over. i thought you meant the sliding surfaces. I do not think I have ever heard of a wood machine having scraped in surfaces like many metal working machines will have. Any thing around 1/1000 is plenty good for wood working.
Bil lD.

Oh I see what you're saying...you mean the table alignment ways on the front and back that are machined into the casting. Yea I want those flat too...but I figured the table would be more important? No?

And I was just aiming to be able to measure and setup the machine to what the manual stated, if I could. It said 0.001 from knives-to-bed as measured across the bed as a reference, so that's what I was aiming for.

And appreciate the replies, thank you.

[Bill Dufour]

I read years ago that. height difference of 1/1000" is the point at which the human eye can spot a step in a wood tabletop before finishing. Not using a ruler or anything, just looking at an angle in decent lighting.
Bil lD

[Alan Lightstone]

I read years ago that. height difference of 1/1000" is the point at which the human eye can spot a step in a wood tabletop before finishing. Not using a ruler or anything, just looking at an angle in decent lighting.
Bil lD

Bill, I'll be blown away if that is true. Will make me rethink every piece I've ever made. :eek:

[Brian Holcombe]

I worked in an automotive machine shop, many times we were required to resurface parts becuase the mechanic took a scotchbrite wheel to a machined surface to clean off a gasket.

So if you think you aren’t affecting your table, you are wrong.

A light touch with scotchbrite (by hand!) with light oil as a lubricant.

I don’t see the logic in wrecking a surface to make it pretty, I’d rather have it ugly and flat.

[Brian Holcombe]

Also, as a general rule of thumb a sheetmetal square isn’t qualified to be used as a straightedge. A straight edge is specifically flattened on the edge and usually made with a cross-sectional shape designed to retain flatness.

[Bill Dufour]

Bill, I'll be blown away if that is true. Will make me rethink every piece I've ever made. :eek:


A study came out about two years ago that men can destern about 200 colors, women 1,000!
Bill D

[Kyle Iwamoto]

Razor blade. Living in the rust capital, I did think I've heard all rust removal processes. This is the first I've heard of using a razor blade. I think, can't recall hearing that before. Tried it yesterday, it does get rid of the thin rust spots. Works like a champ. I also used paste wax as a "lube". So I spent yesterday chasing those rust spots. That one I got with the razor blade has been bugging me. Ended up giving my saw a cleaning, vacuuming and wax job too. And ironically, I've been using razor blades as a glue squeeze out scraper, chisel cleaner, finish and/or CA on the lathe bed ways remover. Never thought of getting rust spots..... Oh yeah not to forget scraping down a finish drip/run. But I never get those.....
I just love this forum.
Thanks for that Matt!
Now maybe I have some time for that drill press column rust..... Nah. too hard. LOL.

[Devin Brenan]

I worked in an automotive machine shop, many times we were required to resurface parts becuase the mechanic took a scotchbrite wheel to a machined surface to clean off a gasket.

So if you think you aren’t affecting your table, you are wrong.

A light touch with scotchbrite (by hand!) with light oil as a lubricant.

I don’t see the logic in wrecking a surface to make it pretty, I’d rather have it ugly and flat.

Your response was what I was thinking a good portion of responses were going to be like, but you're in the minority..at least in this thread. Just a few of you responded this way. Most agree that it does affect the table (power tool with certain abrasives) but not to any degree that one should worry about for woodworking, maybe only metalworking like your machine shop example. I've got enough ammo now to make a well-informed 1st try, and I'll check things out with a feeler gauge set to see what was affected and by how much. If I can't live with it, I'll have it resurfaced. Thanks for the reply.

[Devin Brenan]

Also, as a general rule of thumb a sheetmetal square isn’t qualified to be used as a straightedge. A straight edge is specifically flattened on the edge and usually made with a cross-sectional shape designed to retain flatness.

Yea thought about that, but that square and some other woodpecker's squares are all I have that will fit within the 16" table between the raised ends. I have a 48" Starrett straightedge that I think was around $350 to $400 bucks...but nothing that accurate in a smaller size. For what it's worth, I did set that 12" sheet metal square down on my granite surface plate and could not get a 2 thou feeler gauge under either end or the center. Pretty good accounting for Lee Valley...or maybe it was just a good one.

[Brian Holcombe]

Yea thought about that, but that square and some other woodpecker's squares are all I have that will fit within the 16" table between the raised ends. I have a 48" Starrett straightedge that I think was around $350 to $400 bucks...but nothing that accurate in a smaller size. For what it's worth, I did set that 12" sheet metal square down on my granite surface plate and could not get a 2 thou feeler gauge under either end or the center. Pretty good accounting for Lee Valley...or maybe it was just a good one.

If that’s the case I would have it flattened because a depression down the center of the table means that you will be making material that is always crowned on one side.

On the other post you missed my point, my point is that the wheels do have an effect, so much so that surfaces that seal on a gasket could no longer seal after one session with the rotary disk. Whatever the surface becomes, it certainly won’t be flatter after that disk is applied to it.

Anyways that is my opinion based on my experience, do as you please with it.

[Devin Brenan]

If that’s the case I would have it flattened because a depression down the center of the table means that you will be making material that is always crowned on one side.

On the other post you missed my point, my point is that the wheels do have an effect, so much so that surfaces that seal on a gasket could no longer seal after one session with the rotary disk. Whatever the surface becomes, it certainly won’t be flatter after that disk is applied to it.

Anyways that is my opinion based on my experience, do as you please with it.

That's what I was thinking on the table wallow...that the boards would come out crowned, but others are saying on their planers with wallowed beds that if the infeed side bed roller is flat and set higher than all parts of the table anyway as is recommended, that they don't notice any ill effects on the boards. I'm gonna try it out, intrigued.

And no I got your point about the wheels; you're saying they can take off enough to matter. If you read some of the other replies, they're saying otherwise, for woodworking at least. Maybe the difference there is that metal mating machined surfaces like in your example won't tolerate that type of abrading. I'm sure those tolerances are much tighter than a cast iron woodworking surface.

I'll measure the surface with feeler gauges before and after my abrasive work to see how I changed it. Curious now. Will post what I get.

[Brian Holcombe]

Ill effect #2 is that parts finished in the center of the table will be thicker than those finished at the edges, so check for that also.

I generally read the ‘good enough for woodworking’ argument as ‘good enough for the work done in shop of the person making that statement’. There is no one Single standard for what is ‘good enough’ for woodworking.

I also read it as a general excuse for simply not wanting to deal with the hassle and expense of repairing the issue. Fine, totally acceptable and understandable at times.

[Patrick Kane]

Your thread made me check my T17's table last night. I have a .003" dip near the blade using my 48" starrett. Its about 2" wide, and im guessing this is front running a ton of rails/stiles. I understand Brian's point and mostly agree with him on the "good nuff" argument, but that .003" isnt worth the hassle of having the table planed. On a saw, im not even sure how the table's flatness would impact the cut. On a rip, i suppose the blade would be set to 90° by referencing off the .003" dip near the blade, so a 40" rip would possibly be out of square slightly. The planer's performance has a much more direct connection to the flatness of the bed. Like Brian said, in theory it will put a cup in each face, but im curious how much downward pressure your planer is able to exert on a board. For example, can the infeed roller really deform an 8/4 board to match the wear in the table? I honestly dont know. Im guessing it can squish a 3/4" board that is 16" wide, but i imagine that an 8-10" board of some thickness would require a ton of pressure to flatten it to the depression in the bed.

[Devin Brenan]

Your thread made me check my T17's table last night. I have a .003" dip near the blade using my 48" starrett. Its about 2" wide, and im guessing this is front running a ton of rails/stiles. I understand Brian's point and mostly agree with him on the "good nuff" argument, but that .003" isnt worth the hassle of having the table planed. On a saw, im not even sure how the table's flatness would impact the cut. On a rip, i suppose the blade would be set to 90° by referencing off the .003" dip near the blade, so a 40" rip would possibly be out of square slightly. The planer's performance has a much more direct connection to the flatness of the bed. Like Brian said, in theory it will put a cup in each face, but im curious how much downward pressure your planer is able to exert on a board. For example, can the infeed roller really deform an 8/4 board to match the wear in the table? I honestly dont know. Im guessing it can squish a 3/4" board that is 16" wide, but i imagine that an 8-10" board of some thickness would require a ton of pressure to flatten it to the depression in the bed.

I have a similar issue when I rip thin stock with the fence very close to the blade, but my problem is the insert plate and not the table itself yet. Try as I might, I can never get the d*mn insert plate perfectly flush with the table and this messes with the 90 degree cut of the blade and sometimes causes saw marks at certain spots along the rip cut as the top or bottom of the board is tilted into it. If the plate is set too low and the thin piece I'm ripping is light enough, the front left corner of the wood drops and tilts down a bit into the plate and then that tilts the top of the wood over and leftward into the blade, giving me a nice little reminder. If the plate is set too high no matter the size of the wood piece, the front left corner of the wood lifts up a bit and tilts the bottom of the wood more into the blade. In either case, when the wood the hits the end of the insert plate/table transition, I get another reminder. I find that setting the insert plate ever-so-slightly below the table is better. Regardless, you end up with two different angles on your edge, one that starts at 90 and then changes along the cut. I'm probably preaching to the choir.

For the planer, I think you're right about the board thickness (thicker is better for a bed wallow). Also realized I made a mistake in my previous post that you read...I said infeed roller when I meant to say the bed roller on the infeed side. Powermatic recommends that thing be set at around 0.08 above the table level, which as long as that roller is straight, would help to prevent the board from being smashed into the wallow.

[lowell holmes]

You can prevent rust from reappearing Johnsons Floor Wax.

[Bruce Mack]

There's rust and then there's rust. I've never had any issues as far as what you are worried about, when removing light surface with the usual means (R/O sander with a red or grey scotchbrite). If the surface is pitted, that could be a different story. What does the planer table actually look like?

Erik
This is a great thread. My Ridgid jointer has rust pox. Where can I buy scotch brite 5" hook and loop discs? I see them on line in quantity, but I'd like to buy minimally abrasive discs in single or 5-pack quantity, locally preferable but online is OK. Thanks.

[Eric Arnsdorff]

This is a great thread. My Ridgid jointer has rust pox. Where can I buy scotch brite 5" hook and loop discs? I see them on line in quantity, but I'd like to buy minimally abrasive discs in single or 5-pack quantity, locally preferable but online is OK. Thanks.

Bruce you don't need the hook and loop disc. The grocery store variety scotch brite pads will work fine with the RO sander.

[Bruce Mack]

Great. I have those in shop. Thanks!

[Richard Hart]

I kept it simple with my dad's Craftsman 100 table saw. (1964) It's a saw, not a moon rocket so I don't worry about hair splitting tolerances.

Soaking amount of wd-40 on the table.
220 grit on a sanding block.
Cleaned with denatured alcohol to get the wd-40 off.
3 applications of Johnson's paste wax. Slides like crazy!

Errata: machined pulleys and link belt. Might pass the nickel test :D

[Bill Dufour]

EDTA in water will neutralize rust. That the basic formula for evaporust minus some propitiatory ph adjusters. EDTA is safe enough that some people eat it for their health.
Bill D

[Alan Lightstone]

EDTA in water will neutralize rust. That the basic formula for evaporust minus some propitiatory ph adjusters. EDTA is safe enough that some people eat it for their health.
Bill D

Does EDTA leave the same discoloration as Evaporust? Oh, and what is that discoloration? I seem to remember a dark residue left after using it. And, lastly, where does one get EDTA. And yes, it's in many processed foods.

[Bill Dufour]

I bought edta from ebay. It turns the iron gray. must be submerged or a waterline stain will appear. Like all derusting processes it will not affect the carbon in the iron. Unlike electrolysis there is no chance of hydrogen embrittlement and it can be run forever with no chance of eroding good metal. I believe it is safe for wood, aluminum and paint.
Bill D

[Keith Outten]

Sold my company van a couple of months ago and I had to remove the vinyl signs on the sides of the van. I ended up using a polisher and 3M 06060 Perfect It 3000 extra cut rubbing compound with a foam pad. The paint on the van looked factory smooth shined like a new penny.

I have been thinking about using the same technique on the cast surfaces in my shop. I expect that this technique will restore the cast surfaces to a mirror level finish but I can't say for sure until I give it a try. I used this same technique recently on a very old wooden table top with a Formica insert and the results were fantastic, looked just like a new lacquer finish smooth as glass. This table came from the old cafeteria at CNU, it had been abused by students for over 20 years.