Reducing round stock

[Andy BrocklehurstParticipant @andybrocklehurst85292]

I’ve got some 3mm 304 grade stainless steel that I need to reduce fairly accurately as it needs to be a snug fit in a reamed hardened steel 3/32 hole. The pieces only need to be 25mm long.

I realise a lathe would be the tool for the job but I haven’t got one so I was wondering what the best method would be. Would spinning it in my mill and holding a file or sandpaper to it be accurate enough?

Thanks

[Andy BrocklehurstParticipant @andybrocklehurst85292]

[Thor 🇳🇴Participant @thor]

A box tool would be handy. There is also a thread on MEM.

Thor

Edited By Thor on 13/12/2020 19:20:13

[Andy BrocklehurstParticipant @andybrocklehurst85292]

Posted by Thor on 13/12/2020 19:13:44:

A box tool would be handy.

Thor

Would be handy, except I haven’t got a lathe to put one in!

[Thor 🇳🇴Participant @thor]

For such a short distance I assume you could use the same technique with your milling machine.

Thor

[Pete.Participant @pete-2]

Put the steel in your collet chuck, then hold a cutting tool in the vice on the table, line up one axis on center, take cuts with other axis.

[old martParticipant @oldmart]

With that ammount of length verses diameter, you may have to work in stages, only having about 7mm projecting from the collet at a time.

Another way would be to clamp a block of aluminium, or brass about 30mm thick in the milling vise and drill a hole of the same diameter as the rod through it. Leave the X and Y axes stationary, and put the rod in a collet and using plenty of lubricant use the hole as a steady and reduce the diameter as the spinning rod is slowly withdrawn. Figuring out a way to hold a cutting tool is another matter.

It would not be much easier in a lathe because the length is 8 times the diameter.

Edited By old mart on 13/12/2020 20:16:49

[Clive Brown 1Participant @clivebrown1]

FWIW I'd buy some. For example MACC models have 3/32" 303 @ £0.76 p/ft. +postage.

[Anonymous]

Posted by Clive Brown 1 on 13/12/2020 21:26:23:

For example MACC models have 3/32" 303 @ £0.76 p/ft. +postage.

Good steer. Also 304 is a pig to machine – I hate the stuff.

Andrew

[Andy BrocklehurstParticipant @andybrocklehurst85292]

Posted by Clive Brown 1 on 13/12/2020 21:26:23:

FWIW I'd buy some. For example MACC models have 3/32" 303 @ £0.76 p/ft. +postage.

if it was only that easy, long story / process short, I have a piece of 304 ss bar that a pin is passed through and peened to the side of a knife handle, then the whole thing is polished so the pin becomes invisible, so unless it’s the same steel the pin won’t hide properly …….. hard to explain really.

[Phil PParticipant @philp]

It sounds like you need a small lathe adding to your letter to Santa

Phil

[John HaineParticipant @johnhaine32865]

3/32 is 2.38mm. A quick search suggests that 304 stainless is not through hardenable so are you sure you couldn't drill out the hole to 3mm and use the rod you have? Get a 3mm cobalt drill from toolstation.

[Andy BrocklehurstParticipant @andybrocklehurst85292]

Posted by John Haine on 14/12/2020 06:55:27:

3/32 is 2.38mm. A quick search suggests that 304 stainless is not through hardenable so are you sure you couldn't drill out the hole to 3mm and use the rod you have? Get a 3mm cobalt drill from toolstation.

Correct 304 isn’t a hardening steel and drilling to 3mm would be an easy solution but the rest of the construction is set up for 3/32, it’s a faff but getting 3mm rod down to 2.38mm is the easiest route. Unless anyone can point me in the direction of 3/32 304 rod?

[JasonBModerator @jasonb]

Would it notice if you opened the hole up to 2.5mm? If so M-machine do 2.5mm dia 304

[Andy BrocklehurstParticipant @andybrocklehurst85292]

Posted by JasonB on 14/12/2020 08:15:14:

Would it notice if you opened the hole up to 2.5mm? If so M-machine do 2.5mm dia 304

2.5mm might just do the trick, good shout that, didn’t realise M-Machine existed, they stock some good sizes and materials for the knife maker.

Thanks

[Author]

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