Jointing my Menard's Straight Edge

[Paul Simmel]

No joke.

It's aluminum and a 4', and it's crowned just a bit.

I've read here and elsewhere that aluminum can be machined with WW'ing tools. But I don't know for sure what SORT of aluminum that straight edge is.

My jointer's knives are plenty nicked right now, and I'm just about ready to plop in the second set. They are HSS knives, though, not carbide.

I am actually thinking about shaving off a few thousandths to get a straight edge on that sucker. But I'm going to wait until tomorrow morning, AFTER tonight's Norco wears off.

Seriously, though, I'm wondering if there isn't a stronger alloy or something in there, which would possibly change my consideration.

P.S. the SE was purchased for tile work, and has worked like a dream. But wouldn't it be cool if one could joint a cheepo?

[Paul Mayer]

You can do it on your jointer, but not on mine. :)

I would say you are taking a big risk since you don't know the composition of materials in the straight edge. If you do it, let us know how it goes.

[Dave Verstraete]

Paul

My day job is machining metals but I've never tried aluminum on a jointer. I would stay on the side of caution until somebody that has done it before chimes in. How would you hold it? I think you're right that it might spoil those blades.

[Jeff Wittrock]

I'd tape some sandpaper on your jointer table and just use that to take a little material off. I don't own a jointer, but the thought of those blades touching that aluminum makes me cringe :eek:.

-Jeff

[matt dumney]

Do it! But the sandpaper idea seems better,

[Gary Keedwell]

How about using a router mounted on a table with a split fence and using it with a good HSS or carbide router bit? A spiral bit will cut aluminum like butter. Just take small chips.
Gary

[Paul Simmel]

I swear it, people machine aluminum on these forums!

Been thinking about how to hold it. I could make a block or two, no problem. Holding it against the fence would be easy.

I'm not worried about the knives. They are nicked-up, but I have the Makita knife sharpening system with the green wheel. I've a project coming up, and I'm going to be doing the jointer and planer knives anyway.

I've hit aluminum before, not on purpose, mind you, but it is very soft and saw blades and shaper cutters go right through it. This straight edge is only 1/8" or so thick... not a lot of resistance there.

But I'm going to see who chimes in... good advice. (Laughing) But I'm probably going to do it anyway! Just a hair should do it.

[Gary Keedwell]

How about using a router mounted on a table with a split fence and using it with a good HSS or carbide router bit? A spiral bit will cut aluminum like butter. Just take small chips.
Gary
Thought I would bump my answer down since we posted the same time.:rolleyes:;)

Gary

[Mike Heidrick]

On my jointer the blades cost a lot more than a really nice lee valley straight edge. Doubt I would do this on mine.

[Jason Roehl]

There are a lot of silica-rich woods out there that do far more damage to your jointer knives than a Menard's aluminum straight-edge. I'm gonna take a wild stab and say that it's not some exotic aircraft-grade alloy. Do a test--take a utility knife and scrape the edge you intend to machine--I bet you at least polish it, if not, take a small shaving. Then you'll know it's not too much for your soon-to-be-retired jointer knives.

[J. Z. Guest]

Use a carbide-tipped straight router bit. Carbide is much harder than your HSS jointer knives.

One basic concept of machining is that the harder the material, the slower the cutter needs to be turning. Therefore, cut aluminum slower than steel but faster than wood.

Slow the router bit down as fast as you can, even with a smaller diameter bit. Be careful to hold the aluminum steady and feed it slowly, so that it doesn't get grabbed by the sharp edge.

[Chris Bruno]

If you're not worried about your jointer knives, then you should be good to go if you can hold the straight edge safely.

I use HSS endmills in my Bridgeport all the time to mill aluminum. Unfortunately, the difference is that I can slow down my cutter.

Be careful on the speed - part.. Too slow would be bad too. What's important when you are machining metals - particularly soft metals such as aluminum - is to keep the chip load per tooth at a certain value. If you're spinning the bit faster, you actually need your feedrate to be higher to maintain the proper chip load. This is one of the reasons that High speed machining works so well. If you feed too slow, you'll gaul and mash the aluminum instead of cut it, and your surface finish will be terrible. Now, all that said, ideally you'd want to take extremely shallow passes with really sharp knives... probably on the order of .020" - if you can even set up your jointer bed that accurately. If you're knives are as knicked as you are suggesting, it might be worth while to run a honing tool over them.

Last thing I might suggest is to wipe a little oil on the edge of the aluminum to help the jointer knives out... I've used HSS endmills, but they're almost all spiral bits and not straight edges..

Good luck! And make sure to tell us how it goes! (But please don't do it if you can't hold the stock safely!)

-Chris

[Paul Simmel]

If you're not worried about your jointer knives, then you should be good to go if you can hold the straight edge safely.

I use HSS endmills in my Bridgeport all the time to mill aluminum. Unfortunately, the difference is that I can slow down my cutter.

Be careful on the speed - part.. Too slow would be bad too. What's important when you are machining metals - particularly soft metals such as aluminum - is to keep the chip load per tooth at a certain value. If you're spinning the bit faster, you actually need your feedrate to be higher to maintain the proper chip load. This is one of the reasons that High speed machining works so well. If you feed too slow, you'll gaul and mash the aluminum instead of cut it, and your surface finish will be terrible. Now, all that said, ideally you'd want to take extremely shallow passes with really sharp knives... probably on the order of .020" - if you can even set up your jointer bed that accurately. If you're knives are as knicked as you are suggesting, it might be worth while to run a honing tool over them.

Last thing I might suggest is to wipe a little oil on the edge of the aluminum to help the jointer knives out... I've used HSS endmills, but they're almost all spiral bits and not straight edges..

Good luck! And make sure to tell us how it goes! (But please don't do it if you can't hold the stock safely!)

-Chris

Chris! You are da' man. That's great advice. I can set my beds up in such a way to just barely scrape a few thousandths off. I am definitely going to try this and I am going to report back.

Jason, also great advice, and will do!

[Pat Germain]

As I understand it, you can use woodworking tools to safely cut and machine nonferrous metal (those which do not contain iron). This would include aluminum, brass and copper.

I learned this from David Marks and watched him do it, in case that helps in the credibility area. :)

[Eric Haycraft]

The problem that I see here isn't that it won't cut it, it is that the results probably won't be good. The jointer would have to be perfectly flat AND perfectly adjusted to get an acceptable level of accuracy out of it. Also, the straightedge can easily flex in the machining process, so it may not end up straight at all even on a perfectly tuned machine. At best, I foresee a menards straight edge in the garbage...at worst I foresee a souvenir mounted on the wall as a reminder to never try that again. If you really want to use the jointer for this experiment, I would suggest attaching the straight edge to a larger board and jointing both..that will take any flex in the straight-edge out of the equation.
If he really wants to do this, the router suggestions are the best.

[Paul Simmel]

The problem that I see here isn't that it won't cut it, it is that the results probably won't be good. The jointer would have to be perfectly flat AND perfectly adjusted to get an acceptable level of accuracy out of it. Also, the straightedge can easily flex in the machining process, so it may not end up straight at all even on a perfectly tuned machine. At best, I foresee a menards straight edge in the garbage...at worst I foresee a souvenir mounted on the wall as a reminder to never try that again. If you really want to use the jointer for this experiment, I would suggest attaching the straight edge to a larger board and jointing both..that will take any flex in the straight-edge out of the equation.
If he really wants to do this, the router suggestions are the best.

I thought about that last night, and will be screwing the SE to a piece of 3/4" ply and run it through that way. Handling it will be safer, too. Will let you know later tonight how it goes.

[Pete Bradley]

Use of woodworking tools for metal is almost as good as electrical for attracting posts that range from hearsay and speculation to dangerous. Machining aluminum with woodworking tools is possible and I've done it in a pinch (never with a jointer), but you're outside what the tools were designed for and you often wind up invoking Murphy's law.

How much did that straightedge cost you at Menards? How good was it to begin with? How likely is that you will get a quality straightedge out of your jointer? How much will new knives cost if you take a divot out of them? Now how much does another Menards straightedge cost?

My recommendation is to take your bent straightedge as a sign that you need to buy a decent one from Lee Valley. Then you can come back and get more advice about that dip in your cast iron table that you never knew or cared about. ;)

Pete

[Ted Jay]

I thought about that last night, and will be screwing the SE to a piece of 3/4" ply and run it through that way. Handling it will be safer, too. Will let you know later tonight how it goes.

How about jointing the edge of a board, cut a groove in the center of that board on the TS, whatever depth you need, slide the SE in and then run it through the jointer?

[J. Z. Guest]

My recommendation is to take your bent straightedge as a sign that you need to buy a decent one from Lee Valley.

This is definitely the safest way to go, both from a safety standpoint and risk-of-damaging-equipment-trying-to-cobble-something-together standpoint.

[David DeCristoforo]

It seems to me that there is a difference between what can be done and what should be done. We have a tendency (human nature?) to want to be able to do anything and this can be an admirable quality.

This question of milling metals with tools and machines designed for woodworking comes up often. It has already been pointed out that HHS bits are commonly used to cut metals. But these are usually mounted in machines that are much more massive than a hand held router. They are run at much slower speeds (yes, you can slow most routers down) and everything is much more solidly fixed. The process is much more controllable and the outcome is much more predictable.

So, as to attempting to run a piece of aluminum stock over a jointer, I am thinking that this is not the smartest thing to try. It would be so much easier, safer, and less likely to do damage to joint two pieces of wood, clamp the "straight edge" between them and file the aluminum flush. For the same reasons, the idea of cutting metal on a table saw does not appeal to me nor is it likely to yield precise results.

Then there is the question of the value of a "straight edge" that is not straight. Hopefully this did not represent a great investment because it it did, I would think about returning it and buying (as Pete suggests) a good quality straight edge. Many years ago I bought a 36" long Starrett straight edge (which is currently selling for around $150). You can believe that this required no additional milling on my part!

YM

[Paul Simmel]

I think I am resenting the effort of some to make me look like some sort of idiot. Is that fair to say?

If I had one complaint about the folks on Sawmill Creek (in a very general sense, and it’s just one, small complaint) it would be how people just can’t stick to the point of the subject, but rather tie one post to the other to the point where comments are off to who knows where.

I see this often. Someone asks a question, and instead of an answer to the questions there’s multiple, “Why don’t you do this instead”, responses with lengthy explanations and step by step instructions.

I fully understand and appreciate the time and effort it takes for these Why Don’t You Do It My Way responses, and there are often very good and sound information in these threads. So I get that. And I tolerate it, and even expect it.

But in this case…. Come on, guys. I’m not trying to save a buck by supplanting a jointed Menard’s straight edge for an expensive and very accurate precision tool. I already explained that machining aluminum is done on WW’ing tooling. I’m not worried about my knives because I know from experience they will not blow up, nor will my jointer explode. I told you I fully plan on re-sharpening the knives anyway, on my Makita sharpening system . They are nicked and in need of replacement anyway, and I said that too.

To those who have honored the OP, I thank you immensely! Your suggestions have been great, and I appreciate all of them.

Thank you.

[Pete Bradley]

I think I am resenting the effort of some to make me look like some sort of idiot. Is that fair to say?

I really don't think so. This is a pretty friendly forum. On the other hand, you might consider the possibility that this experiment isn't worth the inherent risk.


I see this often. Someone asks a question, and instead of an answer to the questions there’s multiple, “Why don’t you do this instead”, responses with lengthy explanations and step by step instructions.


I think one of the great values of this forum is for people to offer alternative solutions, especially when a potentially better/safer approach exists. If you're already convinced you're going to put an aluminum straightedge through your jointer, take precautions and let us know how it goes.

This should be obvious, but eye protection is a must, and you need to take precautions to protect your hands and to avoid injury/damage if the thin straightedge twists on the cutterhead or gets kicked back.

Pete

[David DeCristoforo]

"I think I am resenting the effort of some to make me look like some sort of idiot. Is that fair to say? ... instead of an answer to the questions there’s multiple, “Why don’t you do this instead”..."

Since you are replying to my "contribution" to this thread, I would like to say I think you have completely misconstrued the attempts to answer your question. When you ask for advice on a "public" forum, you are going to get a very wide range of suggestions. And why would you want it otherwise? If everyone thought exactly as you do, there would not be much point in asking anyone else what they think would there? I think the best way to approach this is to simply take the offered suggestions at "face value", do not try to read anything into them and then go with what you feel best about. You will almost always have a complete range to select from... everything from "you gotta be crazy" to "hell yes, my grandmother could do that with her eyes closed".

In addition, you have to remember that what you read is more or less "two dimensional" in that you can't hear the inflection as you would in a conversation. So what you might read as one thing would come across as something completely different when spoken. We tend to hear inflection in our minds when we write and we assume, sometimes, that people are going to read something in the same way we are "hearing" it in our own minds. That's why there are "emoticons"... as a way to add some inflection. Not a great way but better than nothing.

YM

PS I hope this does not sound like a lecture....it's not so intended....

[Eric Gustafson]

The following suggestion is done with the understanding that the author of this suggestion bears no responcibility for results that may result in either damaged tooling or injuries that harm or cause any other bodily injury to the individual who attempts this procedure or other individuals in near proximity. The author further dsicloses that this procedure is untested and results may vary. :D

Now that the legal disclaimer is out of the way, :rolleyes: I would clamp the straightedge between two pieces of lumber, set the depth of cut to the absolute minimum on the jointer, and move the piece though the jointer slowly.

[Chris Padilla]

I think you should use the utility knife trick Jason informed you about but take it a step further and whittle that crown out of the aluminum!!

;)

[Cliff Rohrabacher]

I suggest that you not do it. I can't see this working out well.

[Kevin Groenke]

I'm in the "just do it" camp. As you said, Paul, the knives are not going to shatter and your jointer isn't going to explode.

You'll want to prevent the "straight"-edge from vibrating/chattering as you do this. Completely embedding the aluminum in wood should help significantly.


I say cut a rabbet 1/16 x the width of the straight edge out of a piece of stock a bit longer and wider than the straightedge.

Lay the straightedge in the rabbet.

Screw another piece of stock over the straightedge, being careful to align the "bottom" of the two jig pieces (they could both have rabbets to simplify). Put a screw on both ends of the jig to prevent the edge from sliding out.

Run the sandwich over the jointer. Lightest pass possible, cutting wax can't hurt.

Flip the straight edge over and do it again.

FWIW, I didn't think anyone was making you look like anything, you asked for opinions and got 'em. If you want to be made to look like an idiot, I think woodnet is a better venue.

-kg

I'm late to this post and wouldn't be surprised if you've already done this and are busy checking to see how flat all your machine tables are.

Either way, let us know.

[Eric Haycraft]

Curious minds want to know how it worked out... Post pics if it was a success.

[Paul Simmel]

Haven't read since last post. Hope I didn't ruffle too many feathers.

Huge and easy success. Didn't even phase the knives in the slightest, and this is now one very flat straight edge.

Will post pictures of the process a little later in the day.

[Paul Simmel]

Screwed to ply.

83572

Several passes.

83573
83574
83575

[Paul Simmel]

Knives after passes. Note: the nick you see is outside where jointing occurred. I set the fence inside of the nick (about the only 1" area left on my poor knives which **don't** have nicks.)

83577

Jointed straight edge.

83578

The whole reason this started... the 4' x 6' torsion box... which I thought was 010 off because of the warped SE. The box appears to be dead on... not even a piece of paper can slip under the Menard's **straight** edge.

83579

[Dave Verstraete]

Paul

Thanks for the update.

A for execution

A+ for persistence

[Joe Chritz]

As with all things shop related if it worked and you can still count to ten then all is well.

I would be interested to test that on a precision surface. I'm curious how accurate you can joint a piece. The mechanical accuracy has to be pretty good I bet, judging from the pic.

Joe

[Chris Padilla]

Awesome and congrats!! You also have a nice flat piece of plywood! ;)

[Loren Hedahl]

It is just not going to work.

It will cause your jointer knives to melt and the molten knives will cause your jointer to explode.

The heat will burn your arms and you will have a huge hospital bill.

Add to that your straight edge will not be as straight as it was in the beginning.

Interesting, there is no risk in advising negatively, unless you do it after the operation was successful.

So I'll say it again: "IT JUST ISN'T GOING TO WORK!!!!"

Heh, heh, heh, heh.

[Gary Keedwell]

It is just not going to work.

It will cause your jointer knives to melt and the molten knives will cause your jointer to explode.

The heat will burn your arms and you will have a huge hospital bill.

Add to that your straight edge will not be as straight as it was in the beginning.

Interesting, there is no risk in advising negatively, unless you do it after the operation was successful.

So I'll say it again: "IT JUST ISN'T GOING TO WORK!!!!"

Heh, heh, heh, heh.
http://myweb.tiscali.co.uk/dirtbox/pics/muttley.gif Couldn't help myself. :D

Gary

[Cliff Rohrabacher]

HA HA HA That is soo funny.

Glad it worked out for ya.

how's the finish?

[Paul Simmel]

The finish is good. Little knife marks same as you’d see on wood after jointing or planing. Nice and shiny, too. And just like a crowner-up board, you can watch the ends getting hit first. A few passes later, the whole thing is nice and flat.

The straight edge is as flat as my jointer can make something flat. Chris is correct about the plywood!

Re the router table suggestion, I don’t think that I could have gotten a flatter edge on the RT, due to the limited length of a shorter split fence. I actually don’t have a RT. I have a shaper, and I could have put a spiral bit in it and done it that way, but the bed on the jointer is much longer and much flatter and the whole operation was much faster. I’m not concerned about the knife marks (compared to a perfectly milled smooth surface), because, it lays flat.

This whole process was an absolute riot. I certainly wouldn’t compare my edge to a $150 precision tool milled out of the highest grade of steel, but my edge is very much straighter than what I had, and for my immediate needs it will more than suffice.

There was, IMO, absolutely no danger in what I did. Screwing the SE to a piece of ¾” ply made it very easy to feed in a very stable way. The knives on a jointer naturally pull the work piece downward, and so there would have possibly been some flex had it not been screwed to something more ridged. Also, I took but a hair off per pass… lessening the pull and hence the possible flex. If I hadn’t done this, I’d wager there’d still be a hair’s bit of a crown, no matter how many times I ran it through, due to the pulling motion.

I do not own that precision tool to use as a reference, and the bed on my jointer is but 32” long. I don’t know how the bed of my jointer would reference out measured against the precision tool, either. All I know is that the SE is as flat as my jointer can make something flat.

I apologize if I offended anyone earlier. I had no specific person in mind. This is just my hang up. It’s something that bothers **me**, sometimes. And to be fair, it’s not only here. No one is perfect, I the least. I just get impatient, especially when I’m focused on something that is in the works. So let’s call it my problem, and something I will need to work on.

Have a pleasant evening, everyone.

[Joe Jensen]

Paul, glad it worked out. I didn't go on record, so there is no personal risk here now for me, but I thought it was a decent idea. I've done a fair amount of aluminum with a router and been happy. On the other hand, in College I built a set of amazing speakers for a customer ($3500 in 1982) that were veneered in rosewood and stainless steel. I used like 10 carbide router bits trimming the stainless flush with the edges :eek:

Worked fine except for the tiny red hot pieces of stainless landing all over me. I switched into welding clothes and hat and finished up. Not something I'd do again, but I did a lot later with brass and aluminum with no worreis...joe