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Old-Biker-UK
7th Jan 2017, 07:00 AM
Some time ago I was offered a pro camera tripod, for free as it was missing one of the locking knobs.
Trouble was the knob needed to fit a 34 tooth spline.
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At a loose end after finishing a couple of other projects I decided to have a go at it, turned up a disc of Paxalin (paper reinforced hard plastic) bored to the correct diameter.
Set up the G.H.Thomas dividing attachment and top-slide lever on the Myford. Mounted a cutter (ground to the spline profile by Mark 1 eyeball) in a boring bar.
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Indexing 34 teeth was straight forward (34 hole on the disc, 1 turn + 26 holes)
BTW I don't do sums, I have Machinery's Handbook 1942 edition......
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Went round 3 times with a fine last cut to get a sweet fit.
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Cut the ribbing on the knob with a ball-nosed end mill, again indexed with a piece of G.H.Thomas kit.
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The last image shows the knob in place, held to the inner part with a small grub screw.
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I imagine the original would have been moulded plastic which would have covered the locking nut but I wasn't about to cut the spline into a blind hole.....

Mark

Grahame Collins
7th Jan 2017, 11:19 AM
A nice repair Old Biker

I like to see stuff repaired rather than binning it cos its a bit tricky to fix.

Thanks for posting it.

YBAF
7th Jan 2017, 12:14 PM
I imagine the original would have been moulded plastic which would have covered the locking nut but I wasn't about to cut the spline into a blind hole.....

Exposed cogs be called Steampunk......its all the rage apparently. :cool: