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Re: My Newest Toy
Posted: Sun Sep 04, 2016 2:59 pm
by JPG
dusty wrote:BuckeyeDennis wrote:dusty wrote:I have been grossly over thinking this Main Table Alignment Tool. In reality, two pieces of wood cut to the correct width is all that is required.
Once you have the two pieces of wood (get them to the correct dimension any way you know how), you are ready for a quick and dirty alignment.
Get the Mark into saw mode. Loosen all four trunnion bolts, remove the table insert and drop the table down as far as it will go without altering the horizontal position.
Insert one of the two freshly milled pieces on the left side of the blade where the table insert would be. Now insert the other on the right side of the blade. The table has now positioned itself so that the miter slots are parallel to the blade and the blade is in the center of the cutout.
Tighten the trunnion bolts and you are done.
That is indeed quick & slick! But first, I'd measure the sides of the table-insert slot, to verify they are
precisely parallel to the miter slots.
"precisely parallel" - you do mean "precisely as in wood working" right.
The quickest way to do that is to rip a piece of scrap to the width of your table insert (I think all the Shopsmith inserts are 3") and see how it fits. They are not all precisely the same size. I have four tables and there is some deviation in width but my home made table inserts fit in all of them.
When I make table inserts, I cut them initially oversize and sand for a snug fit. I consider the table cutout to be 3 1/64" wide.
Want to think that through?
The insert hole sides can be precisely parallel to each other and still not be parallel to the miter gauge slots.
Re: My Newest Toy
Posted: Sun Sep 04, 2016 6:13 pm
by BigSky
JPG wrote:dusty wrote:BuckeyeDennis wrote:
That is indeed quick & slick! But first, I'd measure the sides of the table-insert slot, to verify they are precisely parallel to the miter slots.
"precisely parallel" - you do mean "precisely as in wood working" right.
The quickest way to do that is to rip a piece of scrap to the width of your table insert (I think all the Shopsmith inserts are 3") and see how it fits. They are not all precisely the same size. I have four tables and there is some deviation in width but my home made table inserts fit in all of them.
When I make table inserts, I cut them initially oversize and sand for a snug fit. I consider the table cutout to be 3 1/64" wide.
Want to think that through?
The insert hole sides can be precisely parallel to each other and still not be parallel to the miter gauge slots.
Really??? How likely do you believe that is?
Re: My Newest Toy
Posted: Sun Sep 04, 2016 6:17 pm
by sehast
dusty wrote:I have been grossly over thinking this Main Table Alignment Tool. In reality, two pieces of wood cut to the correct width is all that is required.
Once you have the two pieces of wood (get them to the correct dimension any way you know how), you are ready for a quick and dirty alignment.
Get the Mark into saw mode. Loosen all four trunnion bolts, remove the table insert and drop the table down as far as it will go without altering the horizontal position.
Insert one of the two freshly milled pieces on the left side of the blade where the table insert would be. Now insert the other on the right side of the blade. The table has now positioned itself so that the miter slots are parallel to the blade and the blade is in the center of the cutout.
Tighten the trunnion bolts and you are done.
I may not fully understand your objective but it appears to be a quick method to re-check and reset table alignment after it has been initially setup. If that is the case why not simply create your zero clearance insert once you are confident the table is in alignment by whatever method you feel is the most robust. Then keep that insert for re-alignment only.
Re: My Newest Toy
Posted: Sun Sep 04, 2016 6:51 pm
by jsburger
BigSky wrote:JPG wrote:dusty wrote:
"precisely parallel" - you do mean "precisely as in wood working" right.
The quickest way to do that is to rip a piece of scrap to the width of your table insert (I think all the Shopsmith inserts are 3") and see how it fits. They are not all precisely the same size. I have four tables and there is some deviation in width but my home made table inserts fit in all of them.
When I make table inserts, I cut them initially oversize and sand for a snug fit. I consider the table cutout to be 3 1/64" wide.
Want to think that through?
The insert hole sides can be precisely parallel to each other and still not be parallel to the miter gauge slots.
Really???
How likely do you believe that is?
Yes it is really very likely!
Believe what? Both statements are true. The hole sides may or may not be precisely parallel and even if they are they may not be parallel to the miter slots.
Re: My Newest Toy
Posted: Sun Sep 04, 2016 7:13 pm
by JPG
IIRC, the insert hole sides are cast whereas the miter slots are milled.
Re: My Newest Toy
Posted: Sun Sep 04, 2016 7:48 pm
by jsburger
JPG wrote:IIRC, the insert hole sides are cast whereas the miter slots are milled.
That certainly sounds reasonable from a manufacturing stand point. So your previous post is still true. Not sure what BigSky is talking about. Maybe he will explain.
Re: My Newest Toy
Posted: Sun Sep 04, 2016 7:56 pm
by JPG
jsburger wrote:JPG wrote:IIRC, the insert hole sides are cast whereas the miter slots are milled.
That certainly sounds reasonable from a manufacturing stand point. So your previous post is still true. Not sure what BigSky is talking about. Maybe he will explain.
Maybe he assumes too much!
Re: My Newest Toy
Posted: Sun Sep 04, 2016 8:50 pm
by BuckeyeDennis
JPG wrote:IIRC, the insert hole sides are cast whereas the miter slots are milled.
Yep, I went downstairs and measured my 520 table for parallelness earlier today. At first, I thought the insert-pocket sides were parallel to the miter slots to within about 0.005". But I was having trouble getting repeatable measurements with dial calipers. Upon closer inspection, I discovered that those surfaces are indeed cast, and not machined. Furthemore, they have a draft angle for mold release, and so my measurements varied based on how far down I placed the caliper points. So not a very good reference surface.
Re: My Newest Toy
Posted: Mon Sep 05, 2016 5:36 am
by dusty
Of course you used those same calipers and repeatably measured the miter tracks and found them to be well within your .005" pass/fail criteria.
Come on, guys. When does this wood working machine have to meet machine shop standards and when does it not?
BTW, what sort of deviations were you getting when you made your measurements? Inconsistent measurements do not necessarily mean the surfaces in question were inconsistent. Use your calipers and measure a precision setup block ten times. Did you consistently get the same numbers (+-.000)? I doubt it.
Re: My Newest Toy
Posted: Mon Sep 05, 2016 7:20 am
by dusty
To carry this discussion just a bit further, I have measured the table insert on one of my four 510 tables and have found the sides of the table insert cutout to be parallel to within +-.003". The measured width at six differ points is is 3.022" +.002 - .001 (ie the measurements range from 3.021" to 3.024". For MY purposes I call that 1/64" plus a tad. and I consider the sides of the insert to be perfectly parallel.
Now this does not "prove" that the table cut out is parallel to the miter slots but to carry that argument there would be ludicrous.
OBSERVATION RESULTS: Two surfaces need not be milled to be parallel!
Notice NO caliper for this measurement.
This is a 3" setup block and a .023" feeler wedged in tight.