Group Project: Dividing Head - The Build

[Flyinfool]

The chamfer on the small end is to clear the OD of the driven gear when engaged.

 

[rwm]

The chamfer on the small end is to clear the OD of the driven gear when engaged.

I figured that. My gear is only 3.4" dia. so it is not necessary. I can add it if someone makes the 3.6" gear.
BTW I think there will be a clearance problem with a 3.6" gear. As the gear teeth wrap further around the worm, it takes a greater distance to disengage related to the sin of the angle at the edge of the gear. Think about an exaggerated situation where the gear encloses 50% of the worm diameter. It doesn't matter that the tooth depth is only .125. It would take a lot more distance to clear the teeth at the edges.
So far I feel like the 3.4" gear will be very effective if I can get the teeth cut a little deeper. Stay tuned!

 

[Ianagos]

To above that asked the spindle I hope will
Be rebuilt in a few weeks. Not sure on that shouldn’t be more than a month total

I wish some of y’all were local to me… I have a 3axis cnc that sits unused most days. I have a huge backlog of projects since so much stuff went wrong building the new shop.

If anyone is ever on the east side of Atlanta and wants to come visit let me know.

Are there any drawing changes to the trunion or dividing plates? Those are the parts I have material for and I signed up for.


My goal with the trunion is to do all operations from one setup to reduce the chance of runnout etc. then I can just flip it in some bored soft jaws and do the other side facing etc.


If it is needed I also have a cylindrical grinder.

Surface grinder is still a work in progress…. Same with the shaper. And the south end lathe…

Read a little more up above. I do have a tig welder if you want to go with that but also I can look at the price to order some 3.5” stock if we need a larger diameter. I believe I have 3.25” on hand.

 

[rwm]

Lanagos- that sounds great! I will let Jeff have final comment on the 3.25" stock but I think it could be made to work. Have you mic'ed it? Is it over or under?

 

[Shotgun]

Also, there were several options on the table. I think the three are:

• Use a tapered seating
• Add a brass bushing/bearing
• Use the excess thickness of the stock you have as the flange

 

[Ianagos]

I measured the stock it measures around 3.251-3.253 but it is hot rolled and has decent rust on the outside.

I would want maybe .05” to make sure it cleans up. But maybe could do with less if it will help simplify the design

 

[Shotgun]

Give it a quick dip in Evaporust first?
Honestly, I think 1/8" of a ledge is plenty. I've used an air chamfering tool on all the edges, so they are very consistent. If you provide the corner relief going laterally into the trunnion, it should have all but .010" of that 1/8" all the way around. That is, plunge the lathe tool into the trunnion at the inside corner of the clamping ledge. Almost like you were going to install a clip ring.

 

[rwm]

I finished the mill work without a hitch!


The scribed line on the face indicated TDC of the eccentric.



I tried something new this time. Since alignment for these small pins is so critical to pressing, I used a brass bar in the mill to press them in. I know it is not best practice but it worked great!

 

[Ianagos]

Give it a quick dip in Evaporust first?
Honestly, I think 1/8" of a ledge is plenty. I've used an air chamfering tool on all the edges, so they are very consistent. If you provide the corner relief going laterally into the trunnion, it should have all but .010" of that 1/8" all the way around. That is, plunge the lathe tool into the trunnion at the inside corner of the clamping ledge. Almost like you were going to install a clip ring.

Being hot rolled the od of the bar is not perfectly round and has pitting and mill scale

 

[ttabbal]

Looks like @Ianagos has the trunnion in hand.

I could do the trunnion lock/bushing/knob and spindle nut if those are still open.

I can run the spindle indexer as well, found some stock online that would work.

Let me know if anyone else has done them or is planning to.