Strutt Epicyclic Train Clock (maybe?)

[kvom]

I couldn't help myself.  Ordered a second desktop CNC mill.  While the DMC2 Mini is capable, the Nestworks C500 (https://www.nestworks.ai/) has a lot of features that the Mini lacks.  Among these are built-in probing, a tool change, an electric vise clamp, and a 4th axis.  It also has a built-in diode laser.  It's a Kickstarter project, and I won't get it before April. 

It's almost twice the weight of the Mini at 200 pounds, so almost certain to be more rigid.  It also offers an AI-based CAM that will be interesting to explore, although at first I'll stick to g-code.

[Dave Otto]

Looks good!
What are you thoughts on the SMW Mod Vise?

Dave

This is the Gen3 hobby edition.  Using the stock jaws the clamping surface is narrow and clamping pressure is a lot less than a regular screw vise.  But for parts like this they're good, and they're well made.   For something much heavier I'd want to clamp to the plate using the 1/2-20 threaded holes.  The fixture plate is made for this mill.

I have a set of 4 Mitee-Bite clamps, but they use 1/2-13 screws.  I think making a plaate with 1/2-13 holes for the clamps and 1/4-20 clearance holes for attaching to the fixture plate could work pretty well.

Thanks! Sorry I forgot to reply.
Dave

[kvom]

The mill is "almost" finished.  I'm awaiting delivery of a new bearing+motor mount for the X-axis, but I think it's capable of reasonable work where precision is not extreme.  I'm still dialing it in.  The biggest problem I see is that the provided edge finder probe doesn't seem reliable, and the spindle-mounted finders spin too fast to be read easily.  Plus center-finding for small holes is a problem.

Since the NestWorks mill I ordered will have a 4th axis, I'm going to assume the wheels (gears) can be cut there with a normal cutter vs. the tiny endmills.

To start I chose the 'planet arm', which is one of the few steel parts in the clock.  I found some thin mystery steel .06" thick and 1.125" wide.  A 4" long piece was super-glued to painters tape on an aluminum base and left to cure overnight.  The three holes were then drilled on the Bridgeport assuring they're all in a line.  Then the assembly was mounted on the DMS2.  The center hole was drilled and reamed .374" to allow for a press fit on the center collet later.  I used my Haimer Tester to obtain the 0,0 coordinate, but there is very little room here, and it would work only for 1/4" holes or larger.

Then the outer profile was milled using a 3/16" endmill.  The hole for mounting the counterweight was tapped 8-32.  Smith calls for bluing the arm using heat, but I don't know how that will turn out.

[kvom]

The tape+super glue didn't hold up well under the flood coolant, and the part detached at the end, but thankfully no harm done.  Brass will be machined dry.

[crueby]

Should be a fun project and learning curve. I hear 'ticking' in your future!   

[Jasonb]

Jobs like that I do the holes first like you have done. But then use the CNC to drill the same pattern in a sacrificial block. I would drill them tapping size and then thread so the part can be screwed down, make a bush for the larger central hole.

An alternative is to stick down the blank and first do the holes on the CNC. Change to a tapping drill and drill the subplate you then have the added security of the screws for the profiling work.

[kvom]

The mill spindle has little torque at the speeds needed for drilling, so any holes must be machined or drilled elsewhere.  In this case drilling the holes on the Bridgeport guaranteed their positions.  The outer profile didn't require precision.

Tapping the hole in the base and screwed the work down would have worked well.  But I didn't know the coolant would loosen the glue.  Lesson learned.  I could also have left a couple of tabs to connect the part to the rest of the stock.

[Kim]

It could have been the coolant, but it might also have been the heat.  I've had that problem, especially on smaller parts.  The part gets hot and causes the superglue to let go.  The coolant should help dissipate the heat, but still, the piece is very narrow in spots, and the heat from machining might have contributed to it coming loose.

This will be an exciting project!  I'm excited to follow along with your journey.

Kim

[kvom]

I'm still having issues with the X-axis motor mount on the CNC mill, so resorted to manual milling.  I discovered that the quill on my lathe's tailstock is jammed, so it looks like I'll need to look into that soon.

This part is the center pinion, a lantern style pinion with 10 "teeth".  Since its outer diameter is  7/16", I'm making it from 1/2" square brass rod.  Having a 1/5" square collet for the lathe, I could part off a 1/2" length and face both ends.  The final length is .438", so there's room to trim at the end.

On the Bridgeport, the first op was to center find, drill a through hole 7/64", and then ream .126".

Second op is to sport drill the 10 holes using the DRO for positioning, then drill each .10" deep with a #59 drill (.041").

Third op is to reverse the piece in the vise and repeat op2.  Because the stock is square, ensuring that the holes on each side line up is straightforward, as opposed to doing the same with round.  I just had to turn it in the correct direction.

Next time in the shop is using the lathe to make it round.

[kvom]

on the lathe, used 1/2" square collet to turn half down to 7/16", then 7/16" collet to turn the other half.  Then alternated ends to reduce the center to .17" diameter with a parting tool.  Happy with the result.

[crueby]

Nicely done!   

[kvom]

The "escape pinion", which I wanted to do next, is even smaller and requires 1/32" holes for the teeth.  I ordered a set of micro drills from Amazon, so the part will need to wait for the weekend.

[Kim]

That pinion spool looks great, Kvom.   

Those tiny holes are a lot more challenging than one might initially think, aren't they!   

Kim

[kvom]

Those tiny holes are a lot more challenging than one might initially think, aren't they!   

Drilling only 1/8" deep in brass wasn't difficult compared to yours in steel.  I have a small drill chuck that can center the drill accurately. 

[kvom]

I received the micro drill set today.  Smallest is .02"    I'll try out the .031 (1/32") on the other two pinions this weekend.