Whats the bst way t...
 

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Whats the bst way to reduce a bolt head diameter

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I need to reduce the heads of atleast three bolts* to fit a counter bored hole.

What is the most accurate and least faffy may to get something relatively accurate. I have drills and a bench grinder which feels like a quick way to do something silly.

Ideally i would ise a lathe, and indeed... I do actually have lathe... Slight flaw is these are the bolts that hold the chuck together after i lost the originals. Three minimum to hold it together to then turn 6 goodies.

They need to be fairly accurate as the os hee haw lip to work with.


 
Posted : 16/08/2024 1:01 pm
fruitbat and fruitbat reacted
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What size do you need? I could turn them up in my lathe and pop them in the post to you. Otherwise, electric drill and bench grinder but it won't be very accurate.


 
Posted : 16/08/2024 1:03 pm
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Yeah I would stick them in your drill and make a rest so you can lay the drill on something solid while you spin against the direction of rotation and approach the grinder.

I'm always making dowels like that, though on a sander and in wood.

With a more elaborate rest, you could probably rig up something to give you repeatable diameters (near enough)


 
Posted : 16/08/2024 1:04 pm
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What size do you need? I could turn them up in my lathe and pop them in the post to you.

That would be ace!

I need M5x0.8. 6.5mm dia head. 25mm thread length.


 
Posted : 16/08/2024 1:09 pm
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What head is it now, hex , socket, pozi etc ?


 
Posted : 16/08/2024 1:56 pm
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Well there are no bolts at he moment historically they were imperial slot, cap heads from memory, however with judicious use of an m5 tap i am half way to being in action!


 
Posted : 16/08/2024 2:12 pm
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Ignore


 
Posted : 16/08/2024 3:01 pm
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Could you use the drill/grinder method to make some which are ok as a short term bodge, just good enough to hold the lathe together whilst you use it to make some proper decent ones?


 
Posted : 16/08/2024 3:13 pm
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Are you sure they're M5? That's very small, my mini lathe's chuck is held on by M8 bolts and looking online they're usually M6 or M8. Or is it a watchmakers type lathe?


 
Posted : 16/08/2024 4:00 pm
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Its the actual bolts that hold the chuck shell together.

The lathe is um... A bit niche.

One of these  https://www.mig-welding.co.uk/forum/threads/drummond-round-bed-lathe-no-1.82954/

With the same treadle motor. The particular chuck is a 3inch chuck, its the only one that currently has a backplate so once i get this one back in action i can bootstrap it.


 
Posted : 16/08/2024 4:07 pm
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Cool looking lathe - I've messaged you, I can put them in the post tonight


 
Posted : 16/08/2024 4:15 pm
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I've replied 🙂 cheers!


 
Posted : 16/08/2024 4:39 pm
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I would think of something like a large grub screw. Due to no head on it, something like an M5 would use an M3 hex or allen key

https://www.ebay.co.uk/itm/221524116308?itmmeta=01J5E0JQ0J7YD9SATHV9F8GWPM&hash=item3393ddc354:g:mXwAAOSwGvhT7fYn

Different sizes and lengths available


 
Posted : 16/08/2024 5:34 pm
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A home based lathe - nothing better in the world for turning perfectly good bits of steel into useless swarf!!!!!  (Speaking from experience)


 
Posted : 16/08/2024 5:59 pm

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