Group Project: Dividing Head - Organization and Design

[Flyinfool]

OK Here is the start link to the build thread.

Group Project: Dividing Head - The Build

This will be the build thread for the group built Dividing head we will all be posting notes, pics, vids? of our progress, there can also be discussion about setups or how to do some things, order of operations or anything else that comes up pertaining to making the parts. The original thread...

www.hobby-machinist.com

 

[erikmannie]

I’m still working on the first spindle. This is as far as I got before I had to leave for work:

 

[rwm]

I think you meant to post this in the other thread? Nice though! What is the insert you are using? Are you happy with the finish?
Robert

 

[erikmannie]

Yes, I meant to post this in the other thread.

This is a medium insert from Carbide Depot. The nose radius is 1/32”. I am not quite happy with the finish.

The smaller diameter is not done yet.

 

[rwm]

Well I could use some guidance on inserts for 12L14 if you figure it out. My surface finish has not been excellent either
R

 

[Shotgun]

It's late in the game for a design tweek, but I think this one might be warranted.

When I make the Trunnion Crank arm, I'm going to cut the big hole out with a hole saw. That will leave a big round of 3/4" steel that is ALMOST big enough to serve as the trunnion end cap. Given a 3" saw and a 1/8" kerf, that'll leave 2.75" round.

If we adjust the shoulder of the trunnion, that round would be big enough. Plus, it would be wide enough to put our angle markings on the outside where they would be more visible.

 

[Flyinfool]

3/4 is kind of thick for the caps, especially on the crank side. How good are you at parting or slitting to split that slug in half to make both caps out of it?

If the degree marking is to move to the cap, then there will need to be 2 non symmetric dowel pin holes to make lining it up repeatable. as the cap is loosened and tightened in normal use.

Of course it will also matter if @ttabbal has already got that far on the trunion.

 

[Shotgun]

Some slight confusion. The material would come from the crank, but would be used as the cap. . . on the opposite side.

You are correct that alignment would be the issue, however. I think smoothly fitting screws would be enough accuracy, but that would radically increase the difficulty of the part.

 

[Flyinfool]

It would also have a big impact on the location accuracy of the mounting holes in the trunion.

 

[Ianagos]

Well I could use some guidance on inserts for 12L14 if you figure it out. My surface finish has not been excellent either
R

12l14 is gummy if run as high sfm as you can. I have some cermet inserts that finish well but you need to get up over 500sfm .002” per rev .02” doc that should do it fine. Small nose radius on carbide inserts work better for finishing but you need to still take a doc greater than the nose radius of the tool.