Updated review: SuperBar by MasterGage, Inc.

Page 2 of 2  


error angle would be close enough to 32 degrees to account for your reading. And frankly, 2 degrees is pretty darn close considering that you most likely only have about an inch or two distance.
I came up with my formula by looking at the geometry of the situation. Just looking at a right triangle, what you're attempting to measure is the change in length of side B. However, what you're actually measuring is the change in length of hypotenuse C. For a tilt angle of 0 degrees, you run into the happy situation of both lengths being the same. However, for any other tilt angle, the hypotenuse will always increase in length faster than the side.
B a .............................. ...... c. ...... . A ...... . C ...... . ... b
Now I agree that you always want to have a tilt angle as close to zero as possible. Not only does it give you a better absolute reading on the error, but I suspect that many dial gauges don't like having lateral loads on their spindles and in fact may have a fair amount of "wiggle" in their spindles when a lateral load is applied to them which would tend to make determining the exact tilt angle rather hard to calculate, predict, or measure.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sep 19, 2:39 pm, snipped-for-privacy@smof.fiawol.org (John Cochran) wrote:

Yep. It's not an elaborate setup (mag base, 2,3,4 block, calibrated eyeball, etc.). The result is close enough to say that it verifies your formula.

Good analysis. It's what I was thinking too. For the most part, this is the sort of situation that you read about but never actually experience. Most people don't deliberately tilt the dial indicator off axis with the object being measured. In all my years I've never had the occasion to do it. There's always some way to resolve the issue so that the readings represent the actual geometry.

Yep, you're absolutely right. Using the Offset Bar on the TS-Aligner products solves the reading problem but it does not avoid the lateral forces on the plunger. Some indicators have more "wiggle" than others but for the most part this isn't an issue. There is also increased friction in the movement which reduces sensitivity, but with sufficient pre-load this isn't an issue either.
Some might think that this setup magnifies the reading, making it easier to eliminate small alignment error. Well, not only is the error magnified, but any instability is too. And, blade alignment isn't the only procedure which benefits from having the stylus close to the table surface. Using a square or angle blocks to set the miter gauge benefits greatly as well.
In order of overall perference, I would have to say that using a blade replacement plate is the least desireable solution to the problem. You are far better off doing the alignment over the shorter distance, tilting the indicator, or (my favorite) using an Offset Bar. Marking a spot on the blade and rotating the blade so that all your measurements are with the stylus tip on that spot will always be more accurate, much more convenient (no need to swap out the blade), and much less expensive (just get a $0.49 sharpie).
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Saw Woodsmith just did a review on three different tablesaw alignment jigs. All they tested was tablesaw alignment, though, and they didn't go through the pros / cons of each. Was an unbiased review, though.
Just another $0.02
--
-Steve in Banks, OR
http://woodworking.bigelowsite.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sep 18, 3:01 pm, snipped-for-privacy@see.my.website.below (Stephen Bigelow) wrote:

Hi Steve,
It wasn't a bad article...per se.
Woodsmith gives the impression of an unbiased magazine because they don't take any advertising - as least no "outside" advertising. See p. 51 of the same issue. They sell two of the jigs in their store. The third jig (the one they peeled the product label off of) is in a completely different class than the others (which is why it costs more than the other two combined). From the article, it would seem that "...all three jigs work in the same way." and "...each of these jigs does more or less the same thing...". This is rather misleading information. One of the three jigs does many more things on many more machines than the other two. See my comments previously post in this thread:
http://groups.google.com/group/rec.woodworking/msg/6642d919f649912d
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.