Making indexable tooling

[Chucketn]

I have decided to try making a couple of indexable tools for my current project. I want to make a 90° Countersink, and a 60° dovetail cutter. I will follow Bob Warfields' write up on the dovetail cutter, and Chris Heapys' write up on the countersink.

Bob's Dovetail Cutter http://www.cnccookbook.com/MTMillDovetail.htm

Chris's countersink http://www.astronomiainumbria.org/a...ca/easyweb.easynet.co.uk/_chrish/csknotes.htm

I have been researching/studying insert info and have chosen TCMT inserts for both.
What I can't find is the screw size information for holding the insert on the tool.
Where do you find this info? Do I have to buy the insert and determine the screw from that, or is there a chart or reference for insert mounting screws?
Any other input? Examples of tools you've made?
I have a bit of O1 ½" drill rod (silver steel) to work with, or would regular steel shafting work?

Chuck in E. TN

 

[Chucketn]

Yes, Paddy! It helps a lot. I know I could buy the tools I'm talking about, and the challenge of making them may be beyond my reach. But, I want to try... And I don't have a wad of cash to spend.
I will go out to my shop and look at what I have for materials, review your sugestions and reply.
Thanks again, Paddy!

Chuck in E. TN

 

[Chucketn]

Paddy,
I found some shafting from the rollers on a treadmill. I turned a piece to .625 to fit an R8 5/8" collet. I parted off with a 7/8" length to make the insert holder. I am asuming that the US standard for countersunk socket heads is 82°, and I will be using a 1/4 x20 csk socket head for the project. What would you recommend for an insert?
I will be making the insert holder per Bob Warfields instructions for the dovetail cutter, but the other way around.
If the insert countersink doesn't work, I'll try Chris Hempy's way.

Chuck in E. TN

 

[Chucketn]

Paddy, what do you think of these inserts on E-Bay? I think , if I understand the size designation, that they are 5/8" on one side of the triangle, right?

http://cgi.ebay.com/DORIAN-Milling-...pt=LH_DefaultDomain_0&hash=item1c1244fc1d

I have been researching store bought indexable dovetail cutters and find the cost and styles vary greatly. I have found several that have 2 or 3 inserts. Several refer to the type listed above.
I'm going to have a go at making a dovetail cutter with 3 inserts.

I did make a countersink yesterday. Non insert type, per Chris Heapy's writeup. Came out pretty good, cuts a bit rough though. But it works. First time hardening for me. I didn't temper it yet.

Chuck in E. TN

 

[Chucketn]

So Dave, I would be better off with just 1 insert? Simplifies construction.

Chuck in E. TN

 

[Chucketn]

I turned up a blank for my dovetail cutter. I came in tp photograph it and realized I'd made the face 1 1/8" wide. Too wide!. Back to the shop to reduce the face. If I want the face to cut .750", that would make the insert .375" on a side, right? So I would think the face should be a little less than .750, right?

Chuck in E. TN

 

[Chucketn]

I'm confusing me, too! I put the blank back on the lathe and turned the face to .995 dia., center drilled it and scribed 2 lines at center, 90° to each other for reference.
Bob Warfield , in his write-up, sets up his blank at 30° to the x axis to mill the mount location for his insert. I think I'll wait to do that until I get the insert. I'll make a run to Fastenal tomorrow for the insert, a 4-40 screw and 4-40 tap.
How does it look so far?





Chuck in E. TN

 

[Chucketn]

In descriptions of other indexable tool builds, the builder usually mills or files the pocket such that the back cutting edge just touches the edge for support and to keep the insert from turning. I shouldn't do that?

Chuck in E. TN

 

[Chucketn]

DaveH,
Did you do anything special when milling the pocket on yours? Can you possibly remove the insert and take a picture of it?

Chuck in E. TN

 

[Chucketn]

Thanks for your help Dave. I'll see what Fastenall has for inserts tomorrow and go from there.

Chuck in E. TN