PM66 Oddity

[LarryG]

"cabinetman," by "it," I meant the fence. I have corrected my post to clarify this.

Whether the angle is straight is immaterial. Whether the angle is perpendicular to the blade is equally immaterial. What matters is whether the TUBE is perpendicular to the blade at all points along its length, so that the fence will be parallel to the blade at any setting. The fence locks to the TUBE, not to the angle.

[phi1l]

"cabinetman," by "it," I meant the fence. I have corrected my post to clarify this.

Whether the angle is straight is immaterial. Whether the angle is perpendicular to the blade is equally immaterial. What matters is whether the TUBE is perpendicular to the blade at all points along its length, so that the fence will be parallel to the blade at any setting. The fence locks to the TUBE, not to the angle.

Except in this case where the tube is so close on the right side that the fence can't be used.

[cabinetman]

"cabinetman," by "it," I meant the fence. I have corrected my post to clarify this.

Whether the angle is straight is immaterial. Whether the angle is perpendicular to the blade is equally immaterial. What matters is whether the TUBE is perpendicular to the blade at all points along its length, so that the fence will be parallel to the blade at any setting. The fence locks to the TUBE, not to the angle.

"LarryG" I disagree. It is material that the angle is perpendicular to the miter slots/blade, because, if the tube is evenly spaced to the angle iron (rail), it too will then be perpendicular to the miter slots/blade.
.

[Rich P]

What's really important here is to have the fence itself parallel to the blade/slots. This adjustment is fairly easy and the fence will remain aligned (think of a parallelogram) as long as the tube is not bent. If the front edge of the tube is not true, all bets are off, as that is where the fence registers.

It would be good to know if the row of holes on the bottom of the tube is parallel to the front edge of the tube. If they are drifting off by 1/4" end to end then (IMHO) that is where the proper fix should be done. Once the rails and tube are in place, "future adjustments" should be a non-starter. With elongated holes in the angle, you introduce the possibility of the tube moving.

I think if David had as much time as he has advice on this problem he would be very happy.

[LarryG]

Except in this case where the tube is so close on the right side that the fence can't be used.

That is my point in saying that the WHY of this problem needs to be understood. SOMEthing is wrong; but what, exactly?

The angle might not be straight. The row of holes in the angle might not be straight. The tube might not be straight. The row of holes in the tube might not be straight. Or it might be a combination of any or all of these. In a perfect scenario all elements would be dead straight but since the fence clamps to the tube, the tube's straightness and perpendicularity to the blade at all points along its length is what really matters. Everything else is just an intermediary.

If David slots the holes in the angle and sets the tube a consistent distance away and tightens down all the screws, it doesn't necessarily mean the tube is straight. It could mean that the tube is overpowering the angle and now neither one is straight. That's why I wrote that if the tube is not straight now, he may or may not be able to pull it straight by slotting the holes. Which, again and in turn, is why the root cause of the problem needs to be found and understood.

EDIT: Rich ... Yes. Bingo. Exactly. Thank you.

[crokett]

Wow! Lotta discussion going on.

Or you might try switching the tube ind for end

Can't do that, or at least don't want to. The holes in the tube are not on the center line. They are drilled closer to one edge than the other. Would have to drill and thread new holes in the tube to do that.

Larry, I see your point about a bent tube and will check it for straightness. At least eyeing it, I believe it is straight, just misaligned to the rail. Also, if the tube were bent the bolt holes along it would vary in the degree they are off. They don't. With both ends bolted down, all the bolts fit just fine. The rail would also have to be bent in the same way the tube is. As for this issue causing a problem with the rip fence alignment to the blade, it doesn't, or at least I adjusted that out already. For this to cause a problem with the rip fence, the alignment to the blade would have to be inconsistent across the length (bent tube) and I don't think that is a problem.

Rich, IMO also the problem is with the tube and not the rail. I am going to make a jig tonight to test both and figure out where the problem is.

[Rich P]

The following is based on my PM66 fence which is basically the same as David's.

The front rail member is 1/4 x 2 x 3 angle iron. The 3" leg is bolted to the table, the 2" leg holds the tube. The tube is 1/8" wall, 2 x 3 rectangular iron tubing. I don't think the tube could generate enough torque to deflect the rail, it's just too massive and certainly not by a 1/4".

I think we know what the "hole" problem is, the tube (again, IMHO).