Boxford back gear

[kevin largeParticipant @kevinlarge76611]

While drilling a large hole in back gear the small gear broke into pieces it looks like it's been broken before and locktited n the shaft

My question is how many teeth should there be and what is the pitch is what cutter would I need to make another

[kevin largeParticipant @kevinlarge76611]

[Yngvar FParticipant @yngvarf]

Is it the small gear on the spindle?

Lathes

I think he does a part exchange on the  back gear spindle too.

Edited By Yngvar F on 13/04/2019 21:04:33

[David George 1Participant @davidgeorge1]

Why were you drilling a large hole in your back gear!

David

[Michael GilliganParticipant @michaelgilligan61133]

Posted by David George 1 on 13/04/2019 22:37:28:

Why were you drilling a large hole in your back gear!

David

.

… the wonders of English ambiguity

[not done it yetParticipant @notdoneityet]

You can work out the DP from the diameter and tooth count of the gear which was in mesh with it ( at least, and likely other gears). Now knowing the DP, you could measure the centre to centre distance and work out the other gear tooth count from that. All straight forward once you look up the formulae for sorting out gears.

[Dave HalfordParticipant @davehalford22513]

From the tumble reverse info on that link it looks like the mk2 is 20pa and the mk1 is 14.5pa.

European 20pa cutters are rare secondhand and a lot of new Asian sets are module and not DP, but HPC is another source of machined steel generic 20pa gears.

[kevin largeParticipant @kevinlarge76611]

It looks like a dp16 14.5 pa still not sure how many teeth yet as I can't all the bits

So if someone can confirm that would be great

[SaxalbyParticipant @saxalby]

Just measured the small back gear on my Boxford and it is 24 tooth 1.625 inches OD which makes it 16DP

[BazyleParticipant @bazyle]

If you make the replacement out of aluminium it will be weaker and act as a sacrificial one for future problems. Then also make it narrower so it cannot be in mesh when the bull wheel is retracted for direct drive. This saves the danger of the back gear left hand lever being engaged when the bull wheel is still engaged with the pulley.

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