Incra V120 vs Shopsmith

dusty · Post by **dusty** » Wed Sep 16, 2009 3:39 pm

I just received my Incra V120 and I don't know whether I am pleased or disappointed. If I don't resolve the issue that I am having, I will be both embarrassed for having spent my money and disappointed because I have been quite pleased with my existing miter gauges.

Addition of the MiterSet, to my tool box, has made me even more pleased.

But, before I get into that, I must get at least one question answered.

With it in mind that we are discussing a miter gauge, what do you believe is meant by the two terms "Angular Accuracy" and "Angular Repeatability".

Some background, just in case you have not been drooling over the V120 like I was. The V120 offers angular stops every 1 degree (over 120 degrees of its range).

The V120 employs a miter bar that is adjustable in the miter track to the point where you can eliminate "all sloop" in that mechanical interface. I mean to say, there is NO unwanted lateral movement of the miter bar and yet it travels in the miter track with virtually no drag (friction).

kd6vpe · Post by **kd6vpe** » Wed Sep 16, 2009 3:54 pm

Dusty,
Thank you for the update. I had started drooling when the first messages came out on this. But I then had to remember that I had the MiterSet and it worked pretty darn good for what I needed and that is for segmented bowls.
Now the miter bar slop is a issue, but I don't feel that it makes that much of a difference in accuracy. I could be wrong. I don't have the capabilites to test the difference in angle accuracy between the two. That would be an interesting test. As far as repeatablity I think they both have the same capabilities.

JPG · Post by **JPG** » Wed Sep 16, 2009 3:59 pm

dusty wrote:I just received my Incra V120 and I don't know whether I am pleased or disappointed. If I don't resolve the issue that I am having, I will be both embarrassed for having spent my money and disappointed because I have been quite pleased with my existing miter gauges.

Addition of the MiterSet, to my tool box, has made me even more pleased.

But, before I get into that, I must get at least one question answered.

With it in mind that we are discussing a miter gauge, what do you believe is meant by the two terms "Angular Accuracy" and "Angular Repeatability".

Some background, just in case you have not been drooling over the V120 like I was. The V120 offers angular stops every 1 degree (over 120 degrees of its range).

The V120 employs a miter bar that is adjustable in the miter track to the point where you can eliminate "all sloop" in that mechanical interface. I mean to say, there is NO unwanted lateral movement of the miter bar and yet it travels in the miter track with virtually no drag (friction).

I would say that angular 'accuracy' is the precision to which a given angle is obtained for a 'setting'. i.e. setting = 45º, accuracy = ±xº.

Angular repeatability is the deviation of the angle obtained when setting AGAIN to the same angle AFTER being set to OTHER angle(s) no matter the time or amount of 'other' settings in between.

Repeatability is determined by the durability and lack of sloppiness in the mechanism used.

Accuracy is determined by the manufacturing inaccuracies/variations in producing the mechanism.

A 'device' can have very small repeatability error(s) but at the same time CAN have large accuracy errors.

IIUC the 'v120' has robust indexing capability to achieve repeatability. I am surprised if the 'touted' laser accuracy is not better than the miterset!

P.S. I can see where the bar adjustments COULD affect the 'accuracy'.

dusty · Post by **dusty** » Wed Sep 16, 2009 4:10 pm

kd6vpe wrote:Dusty,
Thank you for the update. I had started drooling when the first messages came out on this. But I then had to remember that I had the MiterSet and it worked pretty darn good for what I needed and that is for segmented bowls.
Now the miter bar slop is a issue, but I don't feel that it makes that much of a difference in accuracy. I could be wrong. I don't have the capabilites to test the difference in angle accuracy between the two. That would be an interesting test. As far as repeatablity I think they both have the same capabilities.

I believe the end product is the ultimate test. Since you are doing segmented turning, the results will speak for themselves. If you angles are OFF they will certainly be visible and if they are NOT VISIBLE they are not off enough to be an issue.

I'll report more later after I have had some time with the V120. Right out of the box, I wasn't happy.

dusty · Post by **dusty** » Wed Sep 16, 2009 4:23 pm

JPG40504 wrote:I would say that angular 'accuracy' is the precision to which a given angle is obtained for a 'setting'. i.e. setting = 45º, accuracy = ±xº.

Angular repeatability is the deviation of the angle obtained when setting AGAIN to the same angle AFTER being set to OTHER angle(s) no matter the time or amount of 'other' settings in between.

Repeatability is determined by the durability and lack of sloppiness in the mechanism used.

Accuracy is determined by the manufacturing inaccuracies/variations in producing the mechanism.

A 'device' can have very small repeatability error(s) but at the same time CAN have large accuracy errors.

IIUC the 'v120' has robust indexing capability to achieve repeatability. I am surprised if the 'touted' laser accuracy is not better than the miterset!

P.S. I can see where the bar adjustments COULD affect the 'accuracy'.

I think that I understand your differentiation between the two.

Check me on this.

If every time I set the V120 to 45 degree, it is at 45 degrees - then I have angular repeatability (at 45 degrees). I could have angular repeatability at 45 degrees and NOT at 22.5 degrees if the index point (at 22.5 degrees) is sloppy.

If I assume that the V120 performs as specified, I should be able to move from 1 index point to the next and measure 1 degree differences between each index point (throughout the entire range).

Of course, this depends on my ability to measure with the required level of accuracy to make this judgment.

Incidentally, I can do all those things using the Shopsmith Miter Gauge, the MiterSet and Wixey.

JPG · Post by **JPG** » Wed Sep 16, 2009 4:34 pm

YES! It would be interesting to see how 'accurate' the v120 is using a device with 10x the 'resolution'.

dusty · Post by **dusty** » Wed Sep 16, 2009 4:37 pm

JPG40504 wrote:YES! It would be interesting to see how 'accurate' the v120 is using a device with 10x the 'resolution'.

I don't think I can help with that but maybe? What do you mean by 10x resolution? My Wixey is accurate to .1 degrees +- X.

beeg · Post by **beeg** » Wed Sep 16, 2009 5:10 pm

Dusty, I'm . What are you unhappy with the V120?

JPG · Post by **JPG** » Wed Sep 16, 2009 5:13 pm

dusty wrote:I don't think I can help with that but maybe? What do you mean by 10x resolution? My Wixey is accurate to .1 degrees +- X.

The incra has an indexing resolution to 1.0 degree. The wixey has a resolution to 0.1 degree. 0.1 x 10 = 1.0!;)

The wixey has ten times the resolution as the v120. Its incremental resolution is 1/10 that of the v120.

dusty · Post by **dusty** » Wed Sep 16, 2009 5:45 pm

beeg wrote:Dusty, I'm . What are you unhappy with the V120?

Beeg, I guess absolutely nothing. I expected it to be "right on" right out of the box. I expected it to be just like my new rip fence was - "right on" right out of the box.

It was off, when tested with the Wixey and with the MiterSet.

After spending some time with it, I learned that the face of the V120 is adjustable.

Following are my conclusions as of now.

I just purchased the Incra V120 while it was being offered by Shopsmith on sale for $84.95. This included, at no additional cost, a small assortment of parts that allow me to attach the Shopsmith Safety Grip.

At first I was a bit disappointed. I put it together and immediately put it to use. The cross cut that was able to make was definitely not square to the edge of the board I cut. I wanted that cut to be &#8220]I haven’t field tested my new V120 yet but I am sure that I will be pleased. It was $85 well spent.[/font]