Whats the bst way to reduce a bolt head diameter

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.

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.

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)

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.

What head is it now, hex , socket, pozi etc ?

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!

Ignore

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?

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?

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.

Cool looking lathe – I’ve messaged you, I can put them in the post tonight

I’ve replied 🙂 cheers!

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

A home based lathe – nothing better in the world for turning perfectly good bits of steel into useless swarf!!!!!  (Speaking from experience)