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Re: Aligning BASE

Posted: Mon Sep 14, 2015 1:54 pm
by JPG
Continuing on!

I think I figgered out why the problem submitting last night. I attempted to change the 'subject'. IIRC, that was possible in the past. :confused:

Oh well.

First a description of my 'height' gauge.
TABLE HEIGHT GAUGE.jpg
TABLE HEIGHT GAUGE.jpg (340.62 KiB) Viewed 1737 times
TABLE HEIGHT GAUGE LEVEL.jpg
TABLE HEIGHT GAUGE LEVEL.jpg (716.36 KiB) Viewed 1737 times
The combination square is clamped into a model makers vise and is vertical as indicated by the spirit level.


The following pix show the beam projected over the main table and the distance above it near the four corners of the table.
TABLE HEIGHT LEFT REAR.jpg
TABLE HEIGHT LEFT REAR.jpg (745.32 KiB) Viewed 1737 times
TABLE HEIGHT RIGHT REAR.jpg
TABLE HEIGHT RIGHT REAR.jpg (690 KiB) Viewed 1737 times
TABLE HEIGHT LEFT FRONT.jpg
TABLE HEIGHT LEFT FRONT.jpg (631.76 KiB) Viewed 1737 times
TABLE HEIGHT RIGHT FRONT.jpg
TABLE HEIGHT RIGHT FRONT.jpg (780.77 KiB) Viewed 1737 times
The indications are:(in '32' ignoring the 'inches')

Left rear Right rear 11+ 10+

Left front Right front 12+ 11+

However the beam is 1/32 low in the rear at the way tubes.

So approximately the height variation is:(in '32')

12+ 11+

12+ 11+

Which indicates a slight tilt down on the right side. Again that is the same slope direction as the left right deviation end to end. However the table is not 50" wide, so it does indeed slope down towards the right.

This means both the main table and the aux table have a slight tilt in the same direction.

The laser level does not provide precision due to the beam height(it is exaggerated in the pix due to I assume optics).

However it does serve as an indicator and I believe can be useful in adjusting the tables to be co-planer and parallel to the way tubes.


Doing so would involve much tweaking and repetition(not unlike other methods).

It provides a fairly quick overview.

It provides the crucial parallel to way tube detail that is not included in 'historical' methods.

It involves good record recording and eye squinting to determine those values.

It is not for everyone, but would serve as a method for those so inclined.

Re: Aligning BASE

Posted: Mon Sep 14, 2015 2:07 pm
by Bruce
Do you guys actually do any woodworking? :)

Re: Aligning BASE

Posted: Mon Sep 14, 2015 2:42 pm
by JPG
Well Dusty 'snuck' one in while ;) I was creating the last one.

I agree a tripod would remove the aux table as a contaminating detail.

However it would merely move the source, not eliminate any contamination.

Again the floor raises an issue. ;)

I am favorably impressed with the spirit level on the top of the laser. However mine is missing the elevation one.

According to the 'manual' the beam accuracy is +- 3/8" at 30 ft. Not sure what that means. Linearity, angular accuracy(horizontal beam vs vertical beam?) or relative to what(spirit levels?).

I like your use of a 'modern' framing square. It serves to average out any local table top variations. However referencing the way tubes with one leads to other problems(you would need a 'perfect' 'pedestal' to set it on(between the way tubes and the square).


As an aside, how accurate are the stamped/cast/whatever scale markings on the 'modern' framing square? :rolleyes:

About that 7"/8" issue. The outside edge of the squares extend out beyond the way tubes(if they did not, they would fall off) so 8" was reasonable. Since the 'setup' was still there, I went out and measured the spacing of the squares. The outer sides of the bodies were over 10" apart.


One thing I did not mention was the reason for being so high off the waytubes. I thought doing so would increase any tilt indication(of the spt bores or table), but in hindsight, I do not think that to be true. It did however eliminate any need to alter anything throughout the entire process.

Dusty, Thank You for the kind words. As a former Tech I totally understand your mindset re injunears.


Finally this method provides finer resolution than a Wixey type level. Notice I was mentioning angles lass than 0.1 degree.

Re: Aligning BASE

Posted: Mon Sep 14, 2015 2:56 pm
by dusty
Bruce wrote:Do you guys actually do any woodworking? :)
Who are you asking, Bruce? I do a lot of wood working but recently I have been restricted for medical reasons. That will soon be over and I'll be back to making sawdust.

Let me flip the question.

Do you ever have any alignment problems that get under your skin? More specifically, can you use your extension on either end of the machine without needing to realign? When you do a main table alignment, how do you determine parallelism to the blade?

Re: Aligning BASE

Posted: Mon Sep 14, 2015 3:22 pm
by JPG
Realize Bruce that the left/right compatibility issue is a very long standing one.

Yes I have been known to make saw dust, but issues such as this make it less pleasurable.

So it is worth the considerable time spent.

Re: Aligning BASE

Posted: Mon Sep 14, 2015 6:14 pm
by charlese
Bruce wrote:Do you guys actually do any woodworking? :)

Good question! This aligning stuff is great for those enjoying screwing around with machinery just as much (maybe more) than re-manufacturing wood. Not my ilk, but just fine for the futzers. (Engineers/mechanics and such). No criticism intended - this is what they like! Wishing them great happiness! :D
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In my case, I spent about 15 minutes aligning my extension table. All I cared about was that I could get a fairly level surface for sawing longer boards. After the extension table was reasonably level with the infeed side I was satisfied. Didn't care and still don't that the outfeed side of the extension table is lower than the main table or that it is tilted a little. After the cut is made I only want a bit of support.

I did not want the outfeed side to be high. That will cause a little drag on the board.

So far, in 15 years or so, I'm still satisfied.

Re: Aligning BASE

Posted: Mon Sep 14, 2015 7:10 pm
by jsburger
Bruce wrote:Do you guys actually do any woodworking? :)
Well, we used to until this topic came up. :eek: :D

Re: Aligning BASE

Posted: Mon Sep 14, 2015 9:18 pm
by Bruce
Don't take offense Dusty. It's a joke.

Re: Aligning BASE

Posted: Mon Sep 14, 2015 10:19 pm
by JPG
Bruce wrote:Don't take offense Dusty. It's a joke.

:D :D :D :D :D :D ;)