Reducing round stock

This topic has 14 replies, 9 voices, and was last updated 14 December 2020 at 11:15 by Andy Brocklehurst.

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13 December 2020 at 19:05 #513306
Andy Brocklehurst
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@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
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13 December 2020 at 19:05 #27823
Andy Brocklehurst
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@andybrocklehurst85292
13 December 2020 at 19:13 #513308
Thor 🇳🇴
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@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
13 December 2020 at 19:20 #513309
Andy Brocklehurst
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@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!
13 December 2020 at 19:23 #513311
Thor 🇳🇴
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@thor
For such a short distance I assume you could use the same technique with your milling machine.

Thor
13 December 2020 at 19:25 #513312
Pete.
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@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.
13 December 2020 at 20:08 #513322
old mart
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@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a collet and using plenty of lubricant use the hole as a steady and reduce the diameter as the spinning rod is slowly withdrawn.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
13 December 2020 at 21:26 #513328
Clive Brown 1
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@clivebrown1
FWIW I'd buy some. For example MACC models have 3/32" 303 @ £0.76 p/ft. +postage.
13 December 2020 at 21:44 #513331
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
13 December 2020 at 22:04 #513333
Andy Brocklehurst
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@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.
13 December 2020 at 23:02 #513336
Phil P
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@philp
It sounds like you need a small lathe adding to your letter to Santa

Phil
14 December 2020 at 06:55 #513351
John Haine
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@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.
14 December 2020 at 08:06 #513359
Andy Brocklehurst
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@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?
14 December 2020 at 08:15 #513361
JasonB
Moderator
@jasonb
Would it notice if you opened the hole up to 2.5mm? If so M-machine do 2.5mm dia 304
14 December 2020 at 11:15 #513386
Andy Brocklehurst
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@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
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