How to determine size of Dovetail required

[joemeier]

I am interested in making a QCTP, and have found some plans on the internet. The first problem is how to determine the size of the 60 degree dovetail cutter required? On most sites that sell them like MSC, they only spec the cutter diameter, but the important item seems to be that the hypotenuse size of the cutter be long enough. Is there some accurate way to determine how long the side (hypotenuse) of the cutter (or the biggest hypotenuse the cutter can make) from the diameter of the cutter?

Any help on selecting (and recommended suppliers) the cutter will be appreciated, since they can be expensive items, and seem to be the item that would determine if it is cost effective to make a QCTP as opposed to buying one and the tool holders.

This is my first posting and I searched for answers here and on the web and did not find any. Hopefully this is the right place to post such a question?

 

[applescotty]

Joe,

Taking a quick look at some of the cutters available, it looks like the diameter of the cutter at the top end is about the same as the shank. If that assumption holds true, then it's just basic trig:

h=((cutter_diameter-shank diameter)/2)/cos 60

Which simplifies to be:

h=cutter_diameter - shank_diameter

I could very well be completely wrong (either with my trig or with my assumptions).

Scott

 

[Stan]

I didn't do any math on the project. I made a bunch of holders for my AXA size tool post with a 3/4" 60° cutter. 1/2" isn't big enough.

 

[zeeprogrammer]

Welcome to the forum joemeier.
There's a welcome thread where you can tell us more about yourself.
Showing pics of what you're up to is also of great interest to us. We love shiny things.

 

[steamer]

What Zee said.. ;D....then we can talk about roll dimensions of dovetails... ;D

Dave