Page 3 of 4
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 8:47 am
by dusty
Gene Howe wrote:Thanks Dusty. That makes sense. I never thought of using the miter gauge too.
The miter gauge is not necessary and using it improves the reliability of your readings only in that it helps assure the relative position of the Wixey.
Gene, you said you wished that it worked on aluminum. I have a miter bar that I use when doing this. This works great but if you try it be aware that the miter bar is not locked in the track and when you tilt the table it and the Wixey may take a fall.
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 9:28 am
by wa2crk
When I use the Wixey to set my tables at an angle I put the fence on the table and let the Wixey rest against the fence when I tilt the table to an angle that I want. I found this method to be accurate, repeatable and easy.
Bill V
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 11:13 am
by JPG
Read(past tense) it.
I believe a 'grating' type device(allows direction sensing as well as positioning) is used(the source of 'resolution').
Since it 'rotates' there has to be a bearing that can exhibit stiction.
Also 'balance' affects the accuracy.
If a pendulum is used('floating circuit board'), the 'other stuff' is what rotates.
And yes dusty, being off axis so to speak will alter the detected angle(think hip roof - the hip rafters are at a different pitch angle than the rafters).
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 1:16 pm
by Gene Howe
wa2crk wrote:When I use the Wixey to set my tables at an angle I put the fence on the table and let the Wixey rest against the fence when I tilt the table to an angle that I want. I found this method to be accurate, repeatable and easy.
Bill V
Another good tip. Thanks, Bill.
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 1:37 pm
by dusty
Gene Howe wrote:wa2crk wrote:When I use the Wixey to set my tables at an angle I put the fence on the table and let the Wixey rest against the fence when I tilt the table to an angle that I want. I found this method to be accurate, repeatable and easy.
Bill V
Another good tip. Thanks, Bill.
Yes! Probably better because everyone has a fence to be used in this matter.
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 2:28 pm
by charlese
Sorry! Hust feel compelled to post here
Don't want to throw water, or slime on this conversation, but it seems to be really over compensating. The newer term is quite anal.
The last time I had to measure precise and repeating angles was when building the rocking chair copying Maloof. Not having a digital angle measuring device (frugal I suppose) I simply used a wood yard stick and a sliding T-bevel. These two tools worked quite well.

- finished chair front.JPG (175.95 KiB) Viewed 9113 times
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 3:18 pm
by Ed in Tampa
charlese wrote:Sorry! Hust feel compelled to post here
Don't want to throw water, or slime on this conversation, but it seems to be really over compensating. The newer term is quite anal.
The last time I had to measure precise and repeating angles was when building the rocking chair copying Maloof. Not having a digital angle measuring device (frugal I suppose) I simply used a wood yard stick and a sliding T-bevel. These two tools worked quite well.
finished chair front.JPG
Charles I agree and the rocker looks wonderful! Really nice job!
As i stated in the last "super" alignment thread, I'm over it. I set up my machine according to Shopsmith directions and it worked absolutely wonderful. I built many things and any misalignment was my fault not the machine initial setup.
Then I started reading about doing alignment this way and that, using this trick or that device. I did each one and before I knew it I had my machine messed up.
I got out my Shopsmith manual and went through basic setup and alignment. My machine is now where it should be. And I ain't checking anything unless I drop a huge 8x8 on it.

Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 3:25 pm
by dusty
Nice looking chair, Charlese. You did a great job but somewhere along the line you did some measuring that required more than just a yard stick. You know that story boards and story sticks can be considered precision devices when the task is to make two or more objects the same.
Check with Roy Underwood. See what he says.
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 8:04 pm
by Gene Howe
I try not to use any measuring device with numbers. 1, 2, 3 blocks, keyway stock and a variety of story sticks do the trick, most of the time.
Of course there are times when a tape or rule is necessary. But only for gross measurement.
Then there was my dad who often said "measure with a micrometer, mark with chalk and cut with a hatchet."
Re: Repeatability, Accuracy or Resolution
Posted: Mon Aug 29, 2016 11:36 pm
by charlese
dusty wrote:Nice looking chair, Charlese. You did a great job but somewhere along the line you did some measuring that required more than just a yard stick. You know that story boards and story sticks can be considered precision devices when the task is to make two or more objects the same.
Check with Roy Underwood. See what he says.
You're right, Dusty. I used a try square to get a handle on the width of the rough boards before laying the plywood pattern on the board. Used 1/4" plywood for all patterns.
The yardstick was used as an extension of the sliding T-bevel during assembly. I thought we were talking about angles.