Strutt Epicyclic Train Clock (maybe?)

[kvom]

First hurdle on the escape pinion.  The .031" drill had no problem in brass .09" deep at 2600 RPM.

[crueby]

Nice!  For drills that small I've always used the numbered 60-80 sets that come in the tiny index cases (or did, anyway) that I had from ship model work, meant more for use with hand pin vises. Never tried the stepped shank type you got. Did you have to 'peck' at the holes to clear chips, or use any oil? The ones I've used are fairly flexible, so really needed a spot drill to get them started without skating, same with these?

[Kim]

Wow!  Only 6 leaves on that pinion!  Or teeth, or pins, or whatever they are called in a lantern pinion.  That's a mighty small pinion!
And the holes came out nice! 
Kim

[kvom]

Nice!  For drills that small I've always used the numbered 60-80 sets that come in the tiny index cases (or did, anyway) that I had from ship model work, meant more for use with hand pin vises. Never tried the stepped shank type you got. Did you have to 'peck' at the holes to clear chips, or use any oil? The ones I've used are fairly flexible, so really needed a spot drill to get them started without skating, same with these?

No pecking or oil.  Very slow feed by hand.  I did spot drill.

[kvom]

Last second disaster.  I was taking the center shaft down to its final diameter when it snapped in two.     I was already leaving extra material as the drawing showed a .089" diameter through hold and a shaft diameter of .094", meaning a wall thickness of .0025".  Not happening.  I was aiming for .10" diameter when it broke.  It may be that should make the center from steel and press the two ends.   

I'm going to Cabin Fever on Thursday, so further progress will have to wait.  I resolved my issue with my lathe's tailstock, so I'll probably concentrate on easier turned parts for a while.

[crueby]

Wow, that WOULD be a very thin wall. Could it be installed on the shaft (solder? loctite? ) then turned to final diameter next time?

[Kim]

Would turning the center diameter first, then drilling the arbor hole second, be a better order of operations for such a thin wall?  Just a thought... 

Kim

[rklopp]

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.

Circling back to this post. I've found that powder-coat masking tape from McMaster-Carr is coolant-resistant even under full flood coolant in a machining center. I put a layer of tape on the sheetmetal blank, a layer on my aluminum "spoilboard," and stuck the tapes back-to-back with cyano. I had pre-drilled and tapped holes in the spoilboard, drilled clearance holes through the glued-down sheet and then put in some safety screws for the heavier profiling cut. Once profiled, the parts came off relatively easily with a single-edge razor blade. I have done the method using regular blue masking tape, and it does not hold nearly as well as the powder-coat masking tape. The latter is thinner, not crinkly, and gives much better control in the thickness dimension (Z).

[kvom]

Would turning the center diameter first, then drilling the arbor hole second, be a better order of operations for such a thin wall?  Just a thought... 

Kim

The problem there is that I'd be holding one end in the 5/16" collet with the other end unsupported before drilling.  Perhaps pre-drilling the shaft 1/16 would act as a guide for the .094" drill.  But in any .002" wall thickness is absurd.  Perhaps a regular toothed gear could be substituted.

[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.

Circling back to this post. I've found that powder-coat masking tape from McMaster-Carr is coolant-resistant even under full flood coolant in a machining center. I put a layer of tape on the sheetmetal blank, a layer on my aluminum "spoilboard," and stuck the tapes back-to-back with cyano. I had pre-drilled and tapped holes in the spoilboard, drilled clearance holes through the glued-down sheet and then put in some safety screws for the heavier profiling cut. Once profiled, the parts came off relatively easily with a single-edge razor blade. I have done the method using regular blue masking tape, and it does not hold nearly as well as the powder-coat masking tape. The latter is thinner, not crinkly, and gives much better control in the thickness dimension (Z).

I have a lot of powder-coat tape, although it's from Easton, not McMC.  Worth a try.

[kvom]

I spent the afternoon making the 'center pinion', which is larger than the two previous ones.  The outer diameter is 7/16.  While I could have sliced offa piece from some 1/2" bar, I started with some 3/4" that I found in the cutoff drawer.  After facing both ends to the desired length, I drilled and reamed the through hole .126".  Then transferred to the mill to drill the 10 lantern .039" holes .095" deep.  Again, the mini drill in the set worked great.

While still mounted, I milled a flat into the part parallel to the fixed jaw.  The depth in Z was over half of the stock length, so that I could turn the work over and have the flat against the jaw.  Thus the orientation of the holes is maintained. 

After drilling the second set of holes, it was back to the lathe.  With one end in a 3/4" collet, I turned the other end to the final 7/16" diameter.  Then replaced the 3/4" collet with a 7/16" collet in order to turn down the other end.  Then used a 1/8" cutoff blade to turn down the center shaft to .165" over more than half the length.  With the part reversed in the collet and live center for support, I completed the turning.   

[Kim]

That pinion spool came out very nicely! 

But if you made it larger, won't that affect the PD of your pinion and bump the whole gear chain out of alignment?  Or maybe you didn't change the size and I misunderstood?

Kim

[kvom]

That pinion spool came out very nicely! 

But if you made it larger, won't that affect the PD of your pinion and bump the whole gear chain out of alignment?  Or maybe you didn't change the size and I misunderstood?

Kim

I just started with larger stock.  Final dimensiond are to plan.

[Kim]

Ah, OK. Makes perfect sense.  Sorry for my confusion!
Kim

[kvom]

I was driving back to the airport from Cabin Fever in a snowstorm on Saturday, and feared getting stuck on the roads, but finally made it to Columbia, MD.   I visited the National Clock and Watch Museum (4th time there), and happened across a Strutt clock in one of the display cases featuring European makers.  There is no label, so I wonder if it is an original from Wigston's factory.  I think I'll email the museum to inquire.

Back home I spent a couple of hours in the shop making three simple brass parts (got to start somewhere).

First is the counterweight for the planet arm.  It's a simple disk 1" in diameter and 3/16" think, with an 8-32 clearance hole.  The only tricky part is holding the piece in the lathe to face it to length.  I used a collet stop to allow the piece to extend a short distance and not fall into the collet when tightening.

Second part is the center collet for the planet arm, a simple turning job.  It is a press fit in the center of the planet arm.

Third part is the crutch collet.  Simple turning step one, following by drilling and tapping a 4-40 hole in the center.  Then reaming 1/8.  Positining for drilling the cross hole done with a collet block in the mill.