Clockmaking - How To Make A Clock In The Home Machine Shop - Part 5 - Cutting The Pinions 

How To Make A Clock In The Home Machine Shop, Part 5, by Clickspring.
In this video I cut the pinions for the clock from drill rod, and then harden, temper and polish them.
Another milling operation carried out on the lathe, using a cross-slide mounted vertical slide, a light duty milling spindle, a Sherline motor/speed control, and the Divisionmaster CNC indexer.
I also make an improvement on my Sherline lathe tailstock polisher, by making a tin lap for polishing the pinion flanks.
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Cameras used in this video:
Panasonic GH5 - amzn.to/2rEzhh2
Panasonic X920 - amzn.to/2wzxxdT
Tools & Shop Products:
Dykem 80300 Steel Blue Layout Fluid, Brush-in-Cap (4oz): amzn.to/2HGPaJJ
"Solidworks 2013 Bible": amzn.to/2FObS1D
"Machinery's handbook": amzn.to/2pi7XE5
Interapid Dial Test Indicator: amzn.to/2FPInwH
Sherline CNC Rotary Table Indexer: amzn.to/2FJXmfv
Dormer A190202 Jobber Drill Set, 1.0 mm - 6.0 mm x 0.1 mm Size: amzn.to/2DR5fdb
Dormer A190203 Jobber Drill Set, 6.0 mm - 10.0 mm x 0.1 mm Size: amzn.to/2ITfeTa
YG1 NC Spotting Drill 8% Cobalt HSS 1/8 to 1/2" 120 Degree 5 Pc Set CNC Machine: amzn.to/2G7ylv6
Sherline Lathe: amzn.to/2pnXM19
Sherline WW collets: amzn.to/2FYZ7F8
For more info on this build, as well as other tool making info, visit www.clickspring...
Abbreviated Transcript:
00:40 So lets get started. I would have preferred to have made these pinions out of EN8 steel, which is a real pleasure to machine, and can also be quench hardened. Unfortunately I don't have any. What I do have is plenty of drill rod, so drill rod it is.
00:52 After cutting to length, I cut a 60 degree taper on the end of the stock.
01:15 So I turned the outside to the correct diameter. And then set up the cutting gear on the lathe. It's pretty much the same as for the wheel cutting. The spindle is indicated square, and the cutter is lined up on the center of the work.
01:38 Although its a bit more critical this time. If the cutter is even a little bit off center, the leaves will have an obvious lean, and the work's ruined. It's also worth mentioning that cutting pinions is a lot more problematic than cutting wheels.
01:51 Brass mills very easily - you can rip into it with the cutter, and providing its all lined up as it should be, its hard to get a bad result. But pinion cutting is something else altogether. For one thing, silver steel is much less forgiving, and really hard on the cutters. So chip control is really important to look after the them.
02:26 To be honest, I'm always a bit on edge cutting pinions, and kind of relieved when its over. It's just so easy to wreck the cutter. I'm taking care of the 8 leaf pinion here, and the 6 leaf was cut in exactly the same way.
04:34 Thankfully it was, but I've had plenty that weren't! The part is then flipped end for end, and given the same facing cut, followed by drilling and reaming. The reamer I'm using here is a piece of the same pivot steel to which this pinion will eventually be bonded. So a nice fit is guaranteed.
05:37 A piece of pegwood shaped to fit the gap, along with a coarse grit, was used to remove some of the tool marks before hardening. OK, ready to be hardened.
06:01 I used this wire basket to hold the part, and I also coated it in a mix of boric acid and denatured alcohol, to keep the scaling to a minimum. A light touch with a file to confirms that the hardening has been successful
08:13 The MDF lap brought up a nice scratch free polish, but you can see its rolling the edges of the leaves, which doesn't look great. So its time to try something better. I put the job on hold for a few days, and ordered in a small round casting of pure tin.
09:11 One shiny new tin lap; lets give it a run. And based on the result, that MDF lap is going in the bin! A tin polisher is definitely the way to go.
John Wilding workshop and clock construction books:
www.ritetimepub...
I purchased mine from Ian Cobb at: www.clockmaking...
Lester Caine - Divisionmaster
medw.co.uk/wiki...
How To Make A Clock In The Home Machine Shop, Part 5, by Clickspring.