45 degree dovetail cutter, is there such a thing as a 45 degree diamond insert?

[playerofpawns]

I have been wanting to make a 45 degree dovetail cutter/holder.

the only possible cutter that would work is a diamond cutter. however, the closest angle I can find is a 35-50 degrees, no 45 degree diamonds to be found.
anyone have any idea how to get this 45 degree angle out of an indexable cutter?
this is the cheepest place I can find the cutter needed to machine the dovetail for the boaring head project. as cutter width is 5/16 instead of the more common 1/4, and cutter diameter is 3/4 so it will fit into the, "less than an inch" opening for the dovetail.

http://www.shars.com/products/view/3057

View attachment boringhead[1].pdf

 

[Jasonb]

A 35Deg nose angle insert will do it. You don't have to have an edge of the tip against both faces being machined. If you mount a 35Deg tip so the bottom edge is 10deg off horizontal the tip will still describe a flat arc and the side will then be at 45deg (35+10) to cut the face of the DT

Jason

 

[playerofpawns]

woohoo1

You are right! thanks!

 

[GailInNM]

playerofpawns,
You will probably get a better response if you will tell people where you are located. Since this is an international forum with members world wide knowing at least the country where you are located is a big help if we are to help located suppliers.

If you can, please put your location in your profile and preferably also in your signature line or avaitar text.

Also let us know what your your interests are and a little bit about yourself with a note in the "Welcome" section of the forum.

Gail in NM

 

[GailInNM]

Looking at Jason's drawing is only half the story. The most common 35 degree inserts only have 5 degrees of side and end relief. If you draw the cutter out looking at the top you can see that the bottom of the insert will contact the surface being cut by the top of the insert if the darius of the cutter is too small. The VBMT insert has a front and side relief of 5 degrees and the smallest common version is the VBMT 21.5. it is 0.093 thick. If the cutting edge is placed on the center line of the cutter, the smallest diameter of the cutter can only be a little under 1-3/8 inch, which I think is larger than the dovetail you are trying to cut.

It is possible to increase the effective front rake by moving the insert cutting edge off center but this also changes the top rake to a negative rake. You can get away with a little bit of negative rake, but the spindle power requirements and rigidity requirement of the mill are also increased.

In practice, even if you do get the cutter diameter down to where it will fit through the dovetail width the first cut will require an almost full depth of cut on both sides of the dovetail and that will be very difficult to do.

There are some special inserts with much higher front rake for use on boring bars and you might be able to find one that will work with a bit of research, but it will probably be easier and cheaper to just use a HSS dovetail cutter.

Gail in NM

 

[playerofpawns]

the dovetail cutter is cheep $20 and that includes S&H I would rather have the cutter anyway. if I am carefull, maby I can get quite a few dovetails out of it. my mill is fairly rigid, its a smaller bridgeport type knee-mill