Group Project: Dividing Head - The Build

I never tried to C'bore that deep.
You could experiment on a piece of scrap to see how it works out. You may need to do a lot of pecking to clear chips.

It would be hard to reach that deep with a boring bar. It would take a solid carbide bar to do it.

The other option is to drill just a bit under size and then run a reamer in to the bottom.
 
I have a micro 100 boring tool on the way. I have thought of a reamer but bc of the reamer being chamfered in the bottom it would not give you the nice flat bottom. I am also held back by a drill chuck for my little lathe that holds a max of 1/4". I ham thinking of making an adaptor to put in my chuck so i can hold bigger drills.

On a second note i finish to tools today i needed to do for my parts. A 45 and 30 chamfer tool. Still need to hone the radius tools.
 
12L14 on the way:
1622033067878.png
It occurs to me that some of these parts are probably best done as matched set. For example, Erik is doing the spindle. To get a close tolerance on the spindle nut is going to be hard without measuring the spindle threads over wires and having a go/no go gauge for the nuts. If you are making both parts then matching the threads by trial with the nut is much easier. If there is slight variation in the spindle threads you might want to have matched pairs that stay together. I suppose if Erik nails every spindle to be identical or we accept a lower class of fit on the nut it could work out. Thoughts?
Non threaded mating parts are easier. I will ream the bore of the shifter so as long as the worm shaft is <9/16 it will go.
Robert
 
Last edited:
I got some work done on part #23-0001.

1622067588413.png

I have questions about boring this out. What is the best approach for a hole this long (3.14"). I was considering drilling undersize and then making each end of the hole concentric with a boring bar, then reaming to final ID. Do you have a better idea? If I drill all the way through, the exit hole may be off concentricity more than I would like?

Robert
 
Last edited:
I would do either a D-bit drill, or exactly what you're suggesting (drill for boring bar clearance followed by boring bar followed by reamer).
 
  • Like
Reactions: rwm
Actually the concentricity of the bore is not critical, the eccentric makes the gear mesh fully adjustable for both centering and backlash. The only things that are critical is that the hole and shaft are both straight so that the shaft will spin nice and the diameter of the hole to be a good fit to the shaft.

I think @ErichKeane idea should work well.
 
Question where could i find Dbits? In high speed steel i have a few carbide ones. I also had trouble finding anything at msc when i typed in dbit
 
Brento said:
Question where could i find Dbits? In high speed steel i have a few carbide ones. I also had trouble finding anything at msc when i typed in dbit
Click to expand...
My understanding is you typically just grind your own out of round HSS stock. There are the Deckel clone D-bit grinders for exactly this purpose.
 
I dont have the money to pick up one of those prob lol. Maybe i should pick up some hss stock idk how much that will be however.
 
Brento said:
I dont have the money to pick up one of those prob lol. Maybe i should pick up some hss stock idk how much that will be however.
Click to expand...
They can be hand-ground as well, but you want the point to be as close to the center as possible. The nice part about a DBit is that they don't walk, they are basically a single point drill bit
 
You must log in or register to reply here.
Back
Top