Accufence Alignment Question

I've been fiddling with my PM2000 and TS-Aligner Jr. today, and I've noticed that the UHMW sub-fence on the Accufence tends to deviate in and out along its length +/- .005 of an inch. I've tried torquing the bolts which attach the fence so that they are all the same, but this doesn't seem to straighten it out. The fence reads the same at the front and back, it's just in between those points that it bows in and out. Is it worth the time to try to iron this UHMW subfence out using paper shims between the subfence and main fence, or am I just being waaaaay too finicky? IMO, any deviation on the fence can potentially translate over to the blade and result in a chattery finish on the cut. Any opinions?

Should be flat IMHO. If it's any consolation, my Bies has more wave than I would expect and no way to correct it other than removing the face which destroys it due to the assembly method. I plan to replace it in the near future. If I had the ability to easily shim mine, I'd be all over it but I am also guilty of being waaaaay too finicky.

It's not that hard to make them right. This shouldn't be an after-purchase activity but here we are.

I would worry about the area around a foot infront of the blade to about 6-8" in back of the blade. I would shim/trim that area flat. Further away from that inboard or outboard I would remove any outward humps in the fence and probably not worry about dips. Also while your at it check for the squarness of your fence to the table.

Thanks for the input, gents. I marked the high and low spots on the subfence, pulled it off the main fence, shimmed the low spots with some masking tape, then reinstalled the subfence. I've got it within .003 of an inch now. A few more strategically placed bits of masking tape I should be able to straighten it out.

The blade, miter slot and fence are all parallel with each other, thanks to the TS-Aligner Jr. The fence and blade are perfectly square to the table surface as well. I also picked up a machinist square from Ed Bennet which I'm using for this process.

Adjusting a real cabinet saw is sooooooo much easier than the agony I had with tuning my previous contractor saw. Heck, the torque from just starting my contractor saw would throw it out of alignment. Those days are behind me now...:o.

Thanks again for the help.

This type of fence face often has the inconsistant result...in fact, I'm contemplating replacing the UHMW faces with laminate-faced baltic birch on my own saw.

Jim - Any sources for this laminated Baltic Birch subfence material or would this be a DIY project? I can appreciate the low friction properties of the UHMW material, but it doesn't appear to be all that stable. Slick, but not stable.

Amen to the ease of adjustments statement. I had my cabinet mounted trunnions aligned faster than I would have been able to find the allen wrench to loosen my PALS on my old contrator saw.

Woodcraft is a source (although a bit pricey) for phenolic laminated ply which would be sweet for this application. There must be others, I'll look around.

I took off the UMHW and put a straight edge on the face of the metal tube. I found that the highs and lows that I had, were caused by raised metal, around a 1/2 to 1" around the screw holes and slight flaring at both ends of the tube. I took a file to the screw holes and ends until the face was flat from end to end. When I reinstalled the UMHW, all was straight or flat. I can only guess that as the holes are punched or drilled, there's some flaring of the metal that goes on and raised portions result. On the ends, depending on how the endplates are installed, the result could be the same. Anyhow, it worked on mine.

Thanks for the info, Glen. I didn't know the phenolic laminated plywood existed.

Derek - I didn't try cheking the flatness of the steel tube...I think that I will go do this now and see what I find. Thanks for the tip :).

Okay...I pulled off my subfence and ran the dial indicator across the length of the steel fence...It's within .003 of an inch with the depression occuring right where I needed to apply my masking tape shims. So the UHMW (Ultra High Molecular Weight for those acronym challenged out there ;)) appears to just be following the contour of the steel fence. I'll just add a little more masking tape and I should be in good shape. I'd still like to try out the phenolic plywood and see if it stays straighter than the UHMW. Thanks again for the insight.

I used a TS-Aligner on my PM66 Accufence when I first got it and noticed some of the same things you did but decided to just get things set as best I could without shimming and see what happened. In practice it's never been an issue with burning or cuts out of parallel, or anything else I've been able to notice. The small variation is certainly smaller than anything I'd try measuring on a piece of wood cut with the saw so I've just left it as is. That UHMW will distort pretty easily though. I've used it for miter slot runners on the bottom of TS sleds and 1/4 or 1/8 turn of a screw through it and into the sled will often make a difference whether it will hang up in the slot or not. If you do change the fence sides out, you can always add the thin UHMW Slik-Tape over that to retain the slipperiness.

Doug - Thanks for the input. I figured I'm being extremely finicky and that .003 to .005 of a inch deviation is pretty meager in the grand scheme of things. But since I've got this alignment tool at my disposal, I'l compelled to tune things as close as possible. I'm glad to hear that you experienced this phenomenon with your Accufence and that it did not result in anything discernible. If I come across some phenolic laminated Baltic Birch, I will give it a try.

I've moved on to parallel-izing my jointer beds...what fun this is. Now I may need to pick up a knife setting jig to reset the knives since I've made adjustments to the beds.

It seems way too easy to fall into this "alignment" mentality. I quickly forget that I'm working with wood and that these .00x adjustments may never really affect the end result of my work. But knowing that these tools are adjusted this closely gives me a bit more confidence in knowing that my cuts will be that more accurate.

I tend to be a nit picker as far as alignment goes and the Bies. fence on my PM66 has about .003" to .005" of wave to it and I'll be .... if I can figure a way to fix it without starting all over again. On my last big old cast iron Darrah James I had a Vega Commercial fence that was neigh dead on. All that said, I don't think it affects the cutting performance.

CPeter