New jointer / twisted fence?

[Dave Rosner]

Just unpacked my shop fox w1741 8" jointer and set er up. I was very please that the out and in feed tables were nice and planar out of the box. Plus both tables were perfectly flat up to .001 using a 36" straight edge.

When I went to set the fence I used my best 12" combo square to square it up. I put the square close to the cutters since I figured that was the most important point for it to be square. Locked it down and all should be good.

However then I decided to check the squareness at different points along the fence and they were noticibly off. All I did was slide the square from near the knives to the back of the fence and you can clearly see light between the square and the fence as I moved it away. Near the knives it looks perfect.

So - did I get a fence that wasn't ground perfectly flat? Or is this normal because it doesn't matter as long as it's square near the knives?

[David Kumm]

I think a fence with a twist is one of the most common complaints and it is not a good deal. A high and long fence is very handy and a joy to use if straight. If it affects the edge reference when you hold the board where it is comfortable, you need a replacement. Jointers tend to cheap out on the fence and attachment brackets so it is good to check the results with a 2-3" thick board so the results are easy to measure. Dave

[Bill Dufour]

You can try to twist it back since it will probably snap back into flat or send the fence back for a replacement. Twisting it has the possibility of cracking it in two. It was not properly stress relived before machining so it set up residual stresses and twisted once it was unclamped.
Bill

[Mike Cutler]

Dave

It needs to be flat. It shouldn't have a noticeable twist, and that will cause you problems in the future.

[glenn bradley]

All good info prior to this. I'll try not to mess it up . . . The biggest boo-boo I see folks perform on jointers is trying to fix a problem that isn't there. I agree the fence is the most likely of the parts of a jointer to show up out of spec. It seems to span all makes and quality levels that use cast iron fences.

It is easy enough to take the fence off and place it face down on one of your tables. This would expose any twist very quickly. This will eliminate or identify the fence as the issue and we can move on. Otherwise we need to look at your assembly and testing methods. The basic method of milling the face of a board and then using that face against the fence, milling an edge and then checking the length of the intersecting surfaces with a square is always a good idea.

If Shop Fox is like Grizzly, their tolerance on things seems to be pretty reasonable between any two spots on a machined surface. My G0490X (cousin to your 1741) came with a fence that was out enough for them to quickly send me a replacement. I had it in 3 days and sent the old one back in the same box, easy-peasy.

All that being said, please ignore people who tell you that the fence only needs to be straight at the cutters, irregularities don't affect your cut and other clap-trap that flies in the face of basic geometry. A jointer is supposed to true surfaces. Part of the usual milling operation is to use one of those already trued surfaces as a reference against your fence. If your fence isn't true, the feed path is fouled as is your cut.

A quick call to Shop Fox should tell you what their expected fence face tolerance is and help you confirm if yours is within spec.

[Andrew Hughes]

I also believe you should joint some wood on edge and see what you get. Your jointer tables would have to be incredibly flat and true for you to rely on them for your reference.
I did have to send a jointer fence back once but it was so bad that it was obvious to even the most casual observer.

[Dan Friedrichs]

I think you need some feeler gauges to answer this question. Light can be seen through a 0.0001" gap, which I assume is well beyond any reasonable spec. 0.002" is probably more than I'd be willing to tolerate, though.

[glenn bradley]

I think you need some feeler gauges to answer this question. Light can be seen through a 0.0001" gap, which I assume is well beyond any reasonable spec. 0.002" is probably more than I'd be willing to tolerate, though.

Dan's post made me think a bit. A piece of typing paper could be used as a feeler for a definite go/no-go test. If I can get a piece of typing paper under something, that's too far for me (20 weight paper is about .004").

[Darcy Warner]

I see this a lot. They are machining castings that are still warm, happens here in the automotive industry as well. It's a product of the just in time manufacturing where no one wants to sit on any inventory.
Castings used to sit for a year or more outside before they were machined.

[Andrew Joiner]

I bought a new made in USA Powermatic jointer in 1970. This was back when they used meehanite castings. It came with a very twisted fence.

[Bill Dufour]

A proper machine shop would take the fresh casting and slowly allow it to cool in a controlled oven for 24 hours or more. Might even cycle the heat up and down for several days if critcial parts. then the machining is done to close to final dimensions then it is unclamped and allowed to rest and or stress relived again then the final light cuts are taken.
Same idea as case hardening of wood. metal casehardens easily and it really is harder on the outer layer. which induces all kinds of internal stresses. remove any metal and it will move to reestablish equilibrium of the stresses.

The problem is all this takes time and extra work clamping and unclamping, moving stuff around so most shops no longer bother. cheaper to replace bad castings afterwords. Especially if most buyers never notice. Foundries used to leave castings outside in the weather for a year to season with heat/cold cycles.

https://en.wikipedia.org/wiki/Tsar_Bell

[David Kumm]

Flat jointer fences have long been a machine problem. Webbed cast iron is a cheap way to get a good result but has always had a stay flat issue. Old jointers used other methods. My Porter fence is a steel plate welded to a backing and then ground flat. To be fair, we are used to paying for price point machines and it costs money to season and add structure to cast iron to keep it flat. Even high end Euro machines are using Aluminum extrusions more often. Dave
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[Darcy Warner]

Flat jointer fences have long been a machine problem. Webbed cast iron is a cheap way to get a good result but has always had a stay flat issue. Old jointers used other methods. My Porter fence is a steel plate welded to a backing and then ground flat. To be fair, we are used to paying for price point machines and it costs money to season and add structure to cast iron to keep it flat. Even high end Euro machines are using Aluminum extrusions more often. Dave
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Odd, most porters I have had (others like YA, Northfield, etc.) had cored fences. They were always flat, heavy, but flat.

[Ted Reischl]

The only thing I question is the method of determining that the fence is twisted. The tables may be flat as the OP stated, but that does not mean they are a good reference surface.

If'n it were me, I would find a true flat surface, not something that I "think" is flat but is known to be flat, like an inspection table in a machine shop and check it out there.

It amazes me how people think things like tables saw tops etc are flat. I had one that had about a 1/16 valley in it, sure made it fun trying to cut tenons!

[Darcy Warner]

Why everyone should own a real straight edge.

[Dave Rosner]

Ok so you all have confirmed that I need to not ignore this. I'm was just using a combo square to check square with tables so now I'll do some more tests. I'll take a straight edge and check it along the sides and across the sides in a X
like I did with my tables. I have feeler gauges and will see exactly how out of flat this thing is. Then I'll ask shop fox if it's acceptable or not.

After I built my router table I stressed over getting the plate flat with the table. I worked on that for a while and just couldn't get it perfectly flush with the table and gave up. I figured I was chasing my tail for no reason. Then I tried to build a divided light window using that table and that slight imperfection showed up on every coping joint where the mulions meet the rails and stiles. Taught me that sometimes even in woodworking precision does matter. Or maybe i
ll throw all the machines out and just learn to do it all by hand...