twisted jointer fence: have machined or buy new?

[Bruce Lowekamp]

I have a 20yo G1018 8” jointer. It’s always been good enough, though never quite perfect. I’ve recently gotten into trying to figure out if I can get it set up better with appropriate straight edges, etc. The good news is that the tables seem to be reasonably flat and co-planar (within the .003/50” tolerance of my straightedge). However the fence is warped/twisted so that it might be 3/32” out of square on one end if the other is square. Those measurements generally match my experience that I’ve been happy with the face jointing but have issues sometimes getting panels to glue up nicely.

Grizzly sells replacement fences (still) for $165. Or I could find a local machine shop to grind it flat. I’m curious if there are reasons to prefer one over the other, and how flat I should ask a machine shop to make it if I go that route? I haven’t searched for local machine shops capable of that work mostly b/c I’m not sure quite how flat it needs to be.

Bruce

[Brian Holcombe]

For $150, buy a new one. Taking 3/32 twist out of that fence will be pretty difficult without making it too thin.

[Mark Gibney]

I'm asking myself the same question. I recently bought a 20 year old DJ-20 and the fence is like a pretzel.
I can have it Blanchard ground for I would guess about $125 - $150, at a place I've used for other flattening. It will be flat, guaranteed.
If I was to buy a new Grizzly fence for my jointer I still run the risk of the new fence being out of flat.
So I guess I'm leaning towards having it ground, but I am interested in hearing other voices.

EDIT: I was writing the above and posted it while Brian posted his response. So the amount to be removed is something to consider.

[John Ziebron]

Bruce, interesting that you posted this question today. I have a G0490X jointer that has the same kind of issue. The bed tables are flat and coplaner within 2-3 thousands but my fence has a twist in it. If I set it up square on the outfeed table it's pretty good for almost that whole distance. But on the infeed table the bottom of the fence starts twisting away at the bottom which I measure at 18 thousands. I decided a couple of days ago to have my fence reground. I am fortunate that my brother has an acquaintance that has a machine shop with a surface grinder with a 48" bed so I don't think the cost will be that much.

The rub here is that I am working on a fixture setup to hold the backside of the fence securely on the magnetic chuck of a surface grinder. As you know, jointer fences are only secured to the machine in the middle of it's back to allow for pivoting and you cannot just bolt a plate in that location to hold it for grinding with the ends hanging out in free space. I am fortunate to be a hobby machinist and can use my mill to prepare the back of the jointer and make the accompanying pieces needed for secure holding. I won't go into all the details here but if you, or anyone else, is interested I can supply pictures and detailed information after I'm finished.

I honestly never thought about buying a replacement fence from Grizzly for a couple of reasons. First, I thought the price would be rather high (although $165 for yours seems pretty reasonable) and secondly, what would be the odds of getting a replacement that is flat enough to be acceptable. I'm not close to being any kind of expert on this subject but I think the biggest contributor to warped and cupped cast iron on machines today is caused by speed of production and not allowing castings to cool slowly. And, of course, this is likely to be worse in China where almost all of our hobby machines are made.

My opinion in your case would be to find a local shop with a large enough surface grinder and take your fence to them for a quote. Unless you have the means to and want to make your own holding fixture I would let them figure that out and include in the quote. If that price is close to or even a bit higher than a new fence I think that would be the way to go. A reground 20 year old fence is much more likely to stay flat than than a new one would be even after a few years like mine.

[Brian Holcombe]

John,

Assuming the castings are around 3/16” thick, seems a lot to ask to take out the .045” per corner to straighten it. Judging by the fact that many of these seem to be twisted it may be safe to assume that these castings are on the thin side.

Might be worth replacing it with a Aluminum bar stock, machined flat.

[Charles Coolidge]

Machine shop will cost you more than buying a new fence, but there's no guarantee the new fence will be any better. Then again cast iron can have built in stresses just like wood so machining it may not pull the twist out. That was the case for a cast iron table I had ground years ago. Maybe attach some 1/4 inch thick aluminum to the fence and have that machined flat on a CNC mill?

[Ron Selzer]

Watching, as my new out of the box Shop Fox has a slight twist in the fence. not enough for me to complain about at the price i paid for this jointer. IF it was at the equivalent Powermatic price then i would complain about it and expect it to be corrected.
For now I will work with it and decide if it bothers me that much. I bought this Shop Fox jointer primarily on low price and overall it has exceeded my expectations. The fence twist is within my expectations at this price point. The tables have a better ground finish than I expected, the overall finish is better than expected.
Ron

[Alex Zeller]

If you can live with a little less width I think I would screw some wood to it. As long as the screws are flat head countersunk well below the face of the wood. That way you can use the jointer to make it flat.

[Ron Citerone]

If you can live with a little less width I think I would screw some wood to it. As long as the screws are flat head countersunk well below the face of the wood. That way you can use the jointer to make it flat.

I would try what Alex posted first. Doesn't cost much to give it a try.

[Mel Fulks]

What I was told many years ago is the castings used to be aged before machining. That de-stressed them, and made sure they stayed good.
I would not pay for another one. They also used high grade Mechanite. Yours was probably machined ok and aged on your time with your money. I would call the manufacturer....then all the woodworking media.

[joe maday]

Years ago I read in an old Powermatic jointer manual about straightening a jointer fence by bending/clamping to a workbench. So...when I needed to straighten the fence on my DJ-20...in the vise it went and I used a pipe wrench to take out the twist....easy does it ...a little at a time.. worked fine...But there might be a difference between old Brazilian castings and newer Taiwanese. you could get close enough to machine without taking off so much.....worst case.... it breaks and you buy a new one........

[Bill Dufour]

Yes cast iron can be bent until it snaps back into alignment. But it may need to bend too far and snap in two instead of bending. It was probably straight when machined but residual stress bent it on the ship and truck bouncing around. Very similar to wood drying and twisting as it moves.ll

[Alex Zeller]

Anyone who has tried to buy from Grizzly knows how often tools are out of stock. That has to translate into the factories trying to make new ones as fast as possible. That doesn't bode well for allowing castings time to finish moving before being machined.

[Ron Selzer]

Back in the 90's remember reading about how Powermatic was having all castings made outside the US. Article had a picture supposedly of when the castings were made in America and laid outside to season in. Went on to talk about how we could expect to see problems with the new castings.
Ron

[Alan Gage]

If you can live with a little less width I think I would screw some wood to it. As long as the screws are flat head countersunk well below the face of the wood. That way you can use the jointer to make it flat.


I did this with an old 8" Delta jointer and it worked well. I used carriage bolts with the heads sunk below the face of the board and then ran it over the jointer to flatten it. The fence drilled much easier (by hand) than I thought it would.

Alan

[michael langman]

Meehanite cast iron was used on all american made machine tools of good quality up until they were put out of business by the japanese and then china. The process of making meehanite cast iron is much more expensive and controlled then making other types of cast iron.
Unless it is specified if it does not say meehanite in the description of the machine then you can assume that the cast iron is inferior and a hit or miss on it's long term stability, and quality.
When machines were made here in the USA most companys had their own foundries and their castings were made at least a year or two in advance of being machined for finish purposes. It was also a good practice to rough machine a casting, let it sit for a while and then finish machine it later. This allowed the casting to stabilize also.
Castings were left outside in the elements in the north too as the temperature changes helped stabilize the casting.

Using a wood subfence on the warped fence is a good idea as the casting may not be worth machining if it was not designed with enough cross ribbing to help keep it straight and flat.
If you try to machine some bosses on the backside to help hold it during grinding it will cause movement issues,so good fixturing is needed .

[Mike Kees]

I have straightened a jointer fence by suspending it between two 4x4's and stepping on it slowly applying my weight. It worked like a charm. I think you could put it in a vise and slowly and evenly twist ,you will feel it "give". Stop at that point.

[David Kumm]

I'm in the subfence camp as I'm not sure they make straight fences for jointers. Dave

[Andrew Hughes]

My experience with jointer fences is they really don’t need to be perfectly flat to get good square edges.
A convex shape from end to end is what I prefer.
This way a small section of the fence can be set square to the outfeed just past the cutter. Pressure is applied at the this spot. Confidence and a sure hand is developed
A badly twisted fence is obviously a bummer. But really only a small section might need to be removed the end that tips a board against your plan.
Good Luck

[Mel Fulks]

I’ve never used a jointer fence that would hold 90 degrees, for glue ups I just do face in , face out... I have seen guys make a good
start on a barrel by not ....emulating me. Fence twist is not acceptable...’course ya gotta be proud that the manufacturer thinks YOU COULD fix it !

[johnny means]

My experience with jointer fences is they really don’t need to be perfectly flat to get good square edges.
A convex shape from end to end is what I prefer.
This way a small section of the fence can be set square to the outfeed just past the cutter. Pressure is applied at the this spot. Confidence and a sure hand is developed
A badly twisted fence is obviously a bummer. But really only a small section might need to be removed the end that tips a board against your plan.
Good Luck
I was thinking the same. Especially with longer boards that may have a little bow along the length.

[Bruce Lowekamp]

Thanks for all the great responses. Though I guess in some sense the answer is ultimately more depressing than I hoped, but at least I know I'm not alone.

For my particular problem, I've decided not to buy a replacement Grizzly fence; it seems like I'm not terribly likely to improve the situation. The wooden secondary fence is obviously the easiest, though I have to make peace with drilling holes in my fence (which feels wrong even though it's twisted). It occurs to me I need to get a countertop for the sink vanity I'm making, and maybe I could get a scrap of granite/quartz about the right dimensions and use that as a fence. Also a bunch of options like buying an aluminum fence from a JJP-10 (not sure I believe it's likely to be flatter, but would be easier to bend back) or various t-tracks.

decisions, decision...

Bruce

[Curt Harms]

Thanks for all the great responses. Though I guess in some sense the answer is ultimately more depressing than I hoped, but at least I know I'm not alone.

For my particular problem, I've decided not to buy a replacement Grizzly fence; it seems like I'm not terribly likely to improve the situation. The wooden secondary fence is obviously the easiest, though I have to make peace with drilling holes in my fence (which feels wrong even though it's twisted). It occurs to me I need to get a countertop for the sink vanity I'm making, and maybe I could get a scrap of granite/quartz about the right dimensions and use that as a fence. Also a bunch of options like buying an aluminum fence from a JJP-10 (not sure I believe it's likely to be flatter, but would be easier to bend back) or various t-tracks.

decisions, decision...

Bruce

You don't want the thickness of any 'subfence' to reduce the capacity of the jointer too much. I've drilled Asian cast iron a couple times, it was uneventful. My JJP-12 has an aluminum extrusion for a fence, I don't detect any distortion.

[Brian Holcombe]

I would not use granite for the fence.

I didn't think about the face plate earlier, but thats' not a bad idea. I think I would just use a sheet of UHMW thick enough to retain its form while you cut it.

[michael langman]

Try using double back tape to put the wood fence on the warped one.

[Paul Haus]

I picked up some plastic sheet material a number of years back. Not sure what it is made of but it's around 1/2" thick by 8" wide and about 4' in length. It's dead flat and even the full length. I used it on an old jointer with a twisted fence. Drilled it to match the fence and shimmed it till it was uniform along the entire length of the machine. Used it that way for a numbe of years and it worked fine for me. I even added it to my 8" Delta when I got that one to have a taller fence and it's worked fine there too.