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Re: Table Line Up

Posted: Mon May 03, 2021 10:40 pm
by edflorence
dusty wrote: Sat May 01, 2021 4:05 am
edflorence wrote: Fri Apr 30, 2021 1:16 pm Basically, yes. But, there has been much electronic ink spilled on this forum discussing just how parallel is parallel and how best to determine it.
Yes there has been but is there now a consensus?
Sorry to be late chiming in on this thread, but it was a busy weekend. Just wanted to take a minute to comment on whether or not there is a "consensus" on how to achieve parallel-ness between miter gage slot and blade. And of, course, with the understanding that such parallel-ness is only one step in the full alignment process. It appears from the discussion so far that there is actually some degree of consensus to be found - we all agree on what is being attempted. We are all trying to get the distance from miter gage slot to a reference surface (blade, plate, sanding disk) the same at any point along the miter gage slot, within acceptable tolerances. Just what those tolerances are depends on the user and the style of work. So far, consensus.

How to go about measuring the distance is where we begin to drift away from consensus. Broadly, I see two camps: there are those who use dial indicators and there are those who do not. The dial indicator folks have provided us with lots of great photos and much interesting discussion. The forum users who are not in the dial indicator camp have been quieter about their methods. I actually have a foot in both camps, so I thought I would describe how I get to parallel. I have used the dial indicator in the past, but these days I use the miter gage and allen wrench method as detailed in PTWFE. PTWFE actually mentions a couple of different methods - first one is dead simple: slide the table up against the reference surface and adjust the table so there is no gap, and the second is little more involved, but not much: use the allen wrench or a 1/4 inch rod and the miter gage to measure the distance. I have found that it is pretty easy to determine if the table is out of parallel this way and if I am interested in quantifying the "out-of-parallelness" it can be done with a simple feeler gauge. I place the allen wrench or the rod from the cross-cut stop block, in the miter gage and extend it so it is snug against a marked tooth or a mark on a sanding disk. But not too snug, as it does not take much pressure to flex the blade or disk. After rotating the blade or disk I move the gage to the same spot/tooth at the other end of the table and note the gap, if any. This gap can be simply measured with a feeler gage if I am so inclined. Last time I checked, I was out about 0.002" according to the feeler gauge. Close enough for me, for sure. Looseness in the miter gage slot does not seem to be an issue. The miter gage bar is adjusted for a close fit in the slot and I keep gentle pressure on the bar against the inside face of the slot.

On a different but related note: another check that I recently started doing was checking the rip fence for plumb. This has always been a routine check on the jointer, but only recently have I started doing it with my saw fences. Surprisingly, the older 500 fences seem to be closer to a dead right angle when locked down then the newer fence. I would be interested in hearing what others have found on this subject.

Re: Table Line Up

Posted: Tue May 04, 2021 8:07 am
by dusty
edflorence wrote: Mon May 03, 2021 10:40 pm
dusty wrote: Sat May 01, 2021 4:05 am
edflorence wrote: Fri Apr 30, 2021 1:16 pm Basically, yes. But, there has been much electronic ink spilled on this forum discussing just how parallel is parallel and how best to determine it.
Yes there has been but is there now a consensus?
Sorry to be late chiming in on this thread, but it was a busy weekend. Just wanted to take a minute to comment on whether or not there is a "consensus" on how to achieve parallel-ness between miter gage slot and blade. And of, course, with the understanding that such parallel-ness is only one step in the full alignment process. It appears from the discussion so far that there is actually some degree of consensus to be found - we all agree on what is being attempted. We are all trying to get the distance from miter gage slot to a reference surface (blade, plate, sanding disk) the same at any point along the miter gage slot, within acceptable tolerances. Just what those tolerances are depends on the user and the style of work. So far, consensus.

How to go about measuring the distance is where we begin to drift away from consensus. Broadly, I see two camps: there are those who use dial indicators and there are those who do not. The dial indicator folks have provided us with lots of great photos and much interesting discussion. The forum users who are not in the dial indicator camp have been quieter about their methods. I actually have a foot in both camps, so I thought I would describe how I get to parallel. I have used the dial indicator in the past, but these days I use the miter gage and allen wrench method as detailed in PTWFE. PTWFE actually mentions a couple of different methods - first one is dead simple: slide the table up against the reference surface and adjust the table so there is no gap, and the second is little more involved, but not much: use the allen wrench or a 1/4 inch rod and the miter gage to measure the distance. I have found that it is pretty easy to determine if the table is out of parallel this way and if I am interested in quantifying the "out-of-parallelness" it can be done with a simple feeler gauge. I place the allen wrench or the rod from the cross-cut stop block, in the miter gage and extend it so it is snug against a marked tooth or a mark on a sanding disk. But not too snug, as it does not take much pressure to flex the blade or disk. After rotating the blade or disk I move the gage to the same spot/tooth at the other end of the table and note the gap, if any. This gap can be simply measured with a feeler gage if I am so inclined. Last time I checked, I was out about 0.002" according to the feeler gauge. Close enough for me, for sure. Looseness in the miter gage slot does not seem to be an issue. The miter gage bar is adjusted for a close fit in the slot and I keep gentle pressure on the bar against the inside face of the slot.

On a different but related note: another check that I recently started doing was checking the rip fence for plumb. This has always been a routine check on the jointer, but only recently have I started doing it with my saw fences. Surprisingly, the older 500 fences seem to be closer to a dead right angle when locked down then the newer fence. I would be interested in hearing what others have found on this subject.
Thanks for the feedback. Yes, that procedure absolutely works and provides for a very accurate setting if the user pursues it. The challenge that I had when using that procedure was in moving the table the desired amount and then not moving it again when I tightened the trunnion bolts. Some of that exists in my latest methodology.

Re: Table Line Up - Miter Gauge

Posted: Thu May 06, 2021 10:45 am
by db5
The parts view for the miter gauge shows the nylon screws (270) but does not show the set screws above them. Reading posts I concluded that all gauges have these. If I back them out until they stop they still block the hole where an allen wrench or 1/4" rod can be inserted. Before I mess something up can I force them further up? Any suggestions on how to best do this?

Re: Table Line Up - Miter Gauge

Posted: Thu May 06, 2021 12:58 pm
by dusty
db5 wrote: Thu May 06, 2021 10:45 am The parts view for the miter gauge shows the nylon screws (270) but does not show the set screws above them. Reading posts I concluded that all gauges have these. If I back them out until they stop they still block the hole where an allen wrench or 1/4" rod can be inserted. Before I mess something up can I force them further up? Any suggestions on how to best do this?
They are set screws, right. The only way to have put them in would have been to screw them in. Now -screw them back out.

Re: Table Line Up

Posted: Thu May 06, 2021 2:22 pm
by db5
These set screws were NOT screwed in from the top. To get them out I have to remove the nylon glides. They should be able to screw up to provide clear passage for 1 1/4" rod or the Allen wrench. Perhaps a manufacturing defect. They top out and won't budge.

Re: Table Line Up

Posted: Thu May 06, 2021 2:34 pm
by dusty
db5 wrote: Thu May 06, 2021 2:22 pm These set screws were NOT screwed in from the top. To get them out I have to remove the nylon glides. They should be able to screw up to provide clear passage for 1 1/4" rod or the Allen wrench. Perhaps a manufacturing defect. They top out and won't budge.
I am surprised but then my miter gauges are all of the same vintage and apparently are constructed differently than yours. How many centuries old are yours. Mine are about two (centuries old that is).

Re: Table Line Up

Posted: Thu May 06, 2021 4:14 pm
by DLB
I checked three, from Greenie, early 90's, and early this millennium. None were threaded all the way up but all were of larger diameter at the top, so if I unscrew the setscrew and turn it upside down the setscrew will fall out. Every year I get bees or wasps that love to build mud nests in just about anything with a hole in it, causing me all kinds of problems. This would be just their style. Don't know if you get those in Ok City. But if yours are clean I'm thinking manufacturing defect. IIWM I'd measure twice and drill once, being careful to identify the thread depth and not go deeper than as needed. I'll measure carefully and send numbers if it will help.

- David

Re: Table Line Up

Posted: Thu May 06, 2021 6:19 pm
by dusty
It sounds as though I failed to describe how mine are. My set screw holes are not threaded all the way to the top. The upper portion of the hole is larger and allows the set screw to fall out once disengaged from the threads.

Opps I just realized that I very cleverly derailed this thread and changed it from a table line up issue to a miter gauge issue. My apologizes to the OP (BigSky).

Re: Table Line Up

Posted: Fri May 07, 2021 9:34 am
by db5
Dusty, I discovered this on closer inspection. I wrongly assumed that they were inserted from the bottom because they weren't thread to the top. I had to remove them from the bottom. I didn't have an 18 tpi tap but did have several 18 tpi Allen screws so, with a Dremel I created a tap and with a lot of effort managed to clean out the threads. Putting the set screws back in was still a very tight fit. I haven't a clue as to what caused this.

Re: Table Line Up

Posted: Fri May 07, 2021 9:57 am
by JPG
Perhaps the threads were 'incomplete'(too shallow from the bottom) or filled with akupunky(sp?).