Help and advice on fixing fence

[JohnW]

While tuning up my G1023 Grizzly table saw, I found the UHMW face on the Shop Fox fence to be wavy and way out of square. It's +10 years old and kinda beat up so I WAS considering replacing the face. But once removed, I checked square of the tubular steel frame and found it to be way off. From front to back I typically cant it out about 0.005 to help wood exit the cut. When measuring the tubular beam referenced from the miter slot, which is square to the blade, it was consistently canted away from the blade the desired amount until just past the blade. The last 18" of the steel angles BACK TOWARDS THE BLADE by 0.022". I don't ever remember dropping or abusing the fence, but I know this is a recent thing. It has been a good square fence up until my last project.

Anyone have any idea on how to fix or bend this tubular steel? Hit it with a big hammer? I've considered making a face and planning down the end to take out the warp, but that could be a hairy project and safety is at stake.

 

[Wyatt Co.]

How thick is the tube?

 

[gmakra]

You could shim the fence 15 thou and that would get you back spec.

 

[JohnW]

How thick is the tube?

tube is 0.122 thick, about 1/8".

 

[Wyatt Co.]

Do you have any metal working experience?

I'd use heat and shock cooling but I'm well rehearsed. If you are not, you can make a mess of it fairly quickly.

 

[ehpoole]

The simplest solution is to either shim the UHMW, modify the UHMW face, or attach an auxiliary fence to the fence in place of the existing UHMW face. Another option, if capable, would be to try and carefully joint the UHMW face so as to smooth and straighten it out (UHMW is quite workable with woodworking tools and equipment), but staying perfectly parallel to the fence may prove challenging during jointing -- though if you never use the backside of the fence that may not matter much since you could readjust the fence square to the blade afterwards.

The waviness, however, is not uncommon with UHMW faces and is caused by the keyhole slots typically cut into the UHMW face, or by the insertion of threaded studs, if used instead, to attach it coupled with the tightening of those attachment bolts. Essentially each attachment point either pulls and compresses an area of UHMW against the fence while simultaneously thinning and removing some of the underlying support (in the case of keyhole slots)...or, in the case of threaded studs, can actually expand and bulge out the area around the studs if they were forced into the UHMW and the stresses not relieved. For most purposes this waviness should average out since material will ride the high spots and there are usually 4-6 such attachment points along the length of the fence, so often not a major issue unless you routinely work with very short lengths of wood.

For my tablesaw, I opted to replace the UHMW face with a taller extruded aluminum face of similar thickness that also offers me T-slots for attaching accessories like featherboards, auxiliary faces, etc. In my case it was primarily because I wanted a slightly taller fence and also desired the T-slots, but such could also solve both of your issues provided you shim it where necessary and do not overtighten the bolts that fasten it to the fence. You will likely also need to modify the cursor by expanding its range a bit (typically just requires drilling and tapping another set of bolt holes) so that it reads correctly unless the aluminum extrusion just happens to be identical in thickness to the UHMW face it replaced or the existing cursor has sufficient adjustment range.

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[Jeff]

Have you called Grizzly and explained the "wavy" UHMW fence? Their part is 508-1 (fence face, $22.50) and maybe a new one is flat, cheap, and beats diddling around fixing your stuff.

 

[junquecol]

Consider replacing current face material with 1/2" BB plywood. You may have to drill new mounting holes. Drill thru fence material, counter sink holes and fasten to fence, shimming as necessary. Then laminate face with Formica, or just forget Formica. My shop built Biese clone doesn't have any laminate on face. It's over twenty years old now.

 

[JohnW]

Replacing UHMW will not solve the issue. The steel box beam is bowed. I have several laminated aux fences that are flat but they also bow in a little at the end. I'll either have to shim a new face, fix the warp in the box beam or buy a new beam or fence. I have little experience with metal working or heat treating steel other then working for a steel erector when younger. Getting that beam straight is my goal but I'm a bit apprehensive to try and heat/bend it. I have some QSWO and am strongly considering making a fence face using it, and shimming the bow out of the fence when installing. A waxed QSWO face should be stable, and I think will look good and work well.

 

[Jeff]

I'll ask the question again. Have you called Grizzly and explained the problem and ask for their suggestions?

The last 18" of the steel angles BACK TOWARDS THE BLADE by 0.022". I don't ever remember dropping or abusing the fence, but I know this is a recent thing. It has been a good square fence up until my last project.

.

I'm not trivializing your concerns but 0.022" off of dead straight for 18" is only about 3/128" (0.023"). It's hard to understand how a 1/8" t square metal tube gets bent suddenly and mysteriously. :icon_scra

 

[JohnW]

Think I got this issue resolved. My son remembers me "bashing" into the fence when we were rolling a heavy load on my out feed table. (G1276 sander) I don't remember doing this but he does? So possibly that put a slight bend in the tube. I have a habit of keeping the fence locked down when not in use. Perhaps I should unclamp when not in use. In any case, I was able to get almost all the bend out of the tube by mounting it in a vise and putting pressure on the end with a come along and a nudge from a sledge. Then made a new face out of QSWO. Waxed it and it's slick and ready to go. My shop is climate controlled so this well seasoned Scott Smith acquired QSWO should remain stable. I think I got lucky because the fence is now almost perfectly straight. I like this better than the UHMW when it was new.

Ethan, I really liked your aluminum face and considered it. But I have several accessories that require both faces to be equal height in order to attach. Thanks all for your replies.