Advice and guidance on repair and restoration techniques.
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The Importance of Alignment of Ratchets

Postby badpenny » Fri Jul 10, 2015 6:07 pm

We don't always see that how useful something we've worked out for ourselves may be to others.
So I'm sharing this tricksy little blighter I found in a vendor, because the same little so and so appears in many different machines and a year or so ago we had a lengthy thread concerning releasing the ratchet on a bandit's handle.

I recently bought a very nice vendor. You may have seen it recently on Ee-BygumBay.
It's complete and works fine, I want to spruce up the paintwork, so dismantled it. The drawer withdrew ok but needed a bit of a shove to go back in again.
This is The Draw Assembly
Drawer Assembly.png
Drawer Assembly.png (116.04 KiB) Viewed 2997 times
The gubbins underneath the drawer was smothered (as usual) in dry grease, so a good dunking in solvent was called for. Basically it's a drawer that slides out without being able to reverse its action until it has traveled the full length, and then on the return journey, again it has to go the full way until another coin can enter. It's the same mechanism that you'll find on a bandit handle or some Allwin payouts. The Pawl (part that clicks over the teeth of the ratchet) has to pass to the end of the row of teeth in order to reverse so it can return.
Clever Stuff Underneath
Clever Stuff Underneath.png
Clever Stuff Underneath.png (169.34 KiB) Viewed 2997 times
Because the Pawl and row of Ratchet teeth are hidden behind other parts I've outlined them.
Pawl and Ratchet
Pawl and Ratchet.png
When the drawer was extracted and ready to reverse I spotted that the front of The Pawl was jamming against the the peak of the first tooth instead of the valley. Hence it would jam. This was what was making sliding it back troublesome. It would be easy to guess it was worn, however examination showed it was like new. Further squinting revealed that the gap the drawer traveled in allowed for about ten thou of sideways movement. Which in turn pivots the axle the Pawl rotates on so that it skews a tiny amount and results in the leading edge hitting the first tooth instead of meshing with it. What to do? By adding a brass shim on the opposite corner it straightened it up.
Brass Shim being placed.
Brass shim.png
Shim Secured
Shim Secured.png
The body of The Vendor sports a lovely large 3d plaque, which I removed in order to repaint.
3d Plaque
I wire brushed it and intend to take a mould from it so I can cast some up, I'll let you know how that goes. I can't see me firing up my gas furnace in this weather though. !!FLAMED!!
Clean and against a thruppeny for comparison.
BP :byee:

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Re: The Importance of Alignment of Ratchets.

Postby moonriver » Sat Jul 11, 2015 3:05 am

Well done that man! An informative piece of simple yet cunning engineering.

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Re: The Importance of Alignment of Ratchets.

Postby slotalot » Sat Jul 11, 2015 7:59 am

No words required..... !!THUMBSX2!!

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Re: The Importance of Alignment of Ratchets

Postby badpenny » Mon Aug 03, 2015 6:08 pm

All finished now, so I rattley can painted it.
I chose non conforming colours as it needed to co-ordinate if it's to be in sight at home. :roll:
I chose vermilion and ivory; and I think will fill it with doggy chews for Pip to spend his 3d pocket money on.

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