Guide bar too loose on new Powermatic tennoning jig PM-TJ, cannot adjust.

[Frankie Hunt]

I got a new Powermatic tenoning jig. The guide bar has two adjustment screws to get rid of the side to side play. Its a typical bar that has a split and the screw jams down and spreads the split. Well..... these screws are almost impossible to tighten enough. I am afraid the hex head will strip out if I put any more pressure on them. If I loosen them, I can see the split gap close completely. I just cannot get them to open up enough. My saws have a standard size slot. (SawStop PCS and a Unisaw). The side to side slop with the screw backed out is .015, the side to side slop with the screw tightened up as far as I can go is .008 and I had to use the long end of the allen wrench for leverage to get this close.

I suppose I could drill a "dimple" dead center of the split and hit it with a wedge (fine nail set?) and spread it out some that way to assist the screw. Looks to be too much hard steel for the screw to move. Perhaps the angle of the ramp that the screw hits is not steep enough. One other odd thing is when trying to remove the screw it gets really tight at one point. (so I did not totally remove the screw)

I just got the jig yesterday and have not called Powermatic yet, nor have I tried to modify it on my on.

I will call them today. Has anyone else seen this issue?

What was the resolution?

[Lee Schierer]

Dimples work for a few times, but ultimately wear quickly. Buy some UHMW tape. Add a strip to one or both sides of your guide bar. It is available in different thicknesses so you may need to shop around to get close to the dimensions you need. I bought some that was .006 and .010 thick that has work on some of my crosscut guide bars to eliminate side play.

[John Lankers]

If you are in a pinch, silver tape (HVAC tape) works too. Not as durable as UHMW though.

[Frankie Hunt]

Problem resolved. I removed the screw and lubed with heavy graphite grease. This made it possible to turn the screw enough to get the bar spread farther apart than before. I then put a 1/4 inch chisel in the crack and gave it a good swift hit with my 2 pound hammer. This bent the bar outward enough that the screw was able to do the adjustment ok.

As a side note: With no lube the screw would turn up to a point and them pretty much stop. I lubed with oil (Kroil) and the screw would turn easier in the process then it would "Jump" while turning. In other words it would turn a bit then stop, with addition pressure it would turn somewhat easy then stop. Much more pressure and it would turn somewhat easy then stop. Until it would go no further. This turning was what I would call "jumpy". With heavy graphite grease, it was linear in its turning, no jumping. It would turn smoothly according to the amount of pressure applied to it, until it would turn no more. Overall the grease improved things a lot, just not enough to solve the initial problem.

[Ray Selinger]

When it comes to handy metal wedges, screwdrivers are great, the taper seem just right. The older solid plastic handled ones work best.