I always learn something here!

[dusty]

This is a comment that was made by another forum member (artman60) today. I must echo his comment because it is also true for me.

The first thing I learned today is that my Incra V120 is adjustable. I should have known that, as long as I have been using a V120, but I did not. I should have read all the documentation that Incra/Shopsmith provided.

I learned that the protractor is adjustable with respect to the miter bar. I just trusted that it was (and have never been dissatisfied). Obviously, it is accurate enough for my work.

http://www.incra.com/manuals/MiterV120_ ... dition.pdf

Now I have a question. How accurately does that protractor need to be adjusted to provide a "perfect 90°" cut? Stated another way; "How Accurate is Accurate"?

[mbcabinetmaker]

"It depends on what the meaning of the word 'is' is.

Bill Clinton
1998

[dusty]

OKAY, Mark. I'm going to attempt to not let you off of the hook quite that easily. As a professional wood worker, what do you consider to be your "most accurate" means of determining a "perfect 90°" cut?

Square Tools 001.jpg (1.65 MiB) Viewed 19277 times

[Gene Howe]

There's always the 5 cut method.
But, for cross cuts, I just make the cut and flip one piece and put them back together. If the edges are perfectly aligned when the edges setting on a dead flat surface, I'm good to go.
If not, out comes the Miterset.

[dusty]

An opinion here.

The five cut method is an excellent way to determine if your table saw and miter gauge are square to one another. But if you run the five cut process and determine that they are not square, how do you go about correcting that situation. Even after using the MiterSet, it is conceivable that you could fail the five cut method.

Incidently, I use the MiterSet whenever my Shopsmith miter gauge is in question.

[mbcabinetmaker]

OKAY, Mark. I'm going to attempt to not let you off of the hook quite that easily. As a professional wood worker, what do you consider to be your "most accurate" means of determining a "perfect 90°" cut?

Square Tools 001.jpg

I have the old shopsmith square that works pretty well and I also use the 2 cuts with a straight edge that Gene mentions. My best method however is how accurately the pieces go together. For example if my doors aren't coming out square it is most often that the miter gauge used for rail cuts is out a bit but it can be that the wood is just not straight or the cutter is dull. No matter how perfect your equipment IS the wood never is. I'm pretty anal with equipment setting and recently spent 2 hours re calibrating my sliding saw table after moving it about 3 feet. You may notice marked lines on the floor in some of my post. That's so I can return a tool to its exact location if I need to move it. One thing is for sure though the more accurate your equipment the better the outcome and the safer it is to operate.

[dusty]

Thank you, Mark. I am certain that the entire forum values your opinions as much as I do.

I am highly dependent upon that Engineer's Square from Shopsmith (730343A).

http://www.shopsmith.com/ownersite/cata ... square.htm

[Gene Howe]

I don't use an Incra miter gauge. My old Kreg is always right on using it's degree indicator as verified occasionally with the Miterset. The Miterset is used for the Shopsmith gauge quite a bit more frequently.
Used to use the engineer's square but, not any more.
The the Kreg and cut method described earlier serves me well.

[JPG]

Two cut???

Like Gene I do a one cut check, but place the resulting two pieces on their ends just cut. The then abutted vertical edges will indicate accuracy. No gap = good. Amount of gap = amount of inaccuracy. The edges compared must have been originally the same edge. That edge(s) need(s) to be straight.

[dusty]

Two cut???

Like Gene I do a one cut check, but place the resulting two pieces on their ends just cut. The then abutted vertical edges will indicate accuracy. No gap = good. Amount of gap = amount of inaccuracy. The edges compared must have been originally the same edge. That edge(s) need(s) to be straight.

So now you know that the cut is not square.