Bright steel

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Bright steel

This topic has 29 replies, 16 voices, and was last updated 5 May 2023 at 17:40 by mark costello 1.

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3 May 2023 at 17:28 #643801
Stephen Follows
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@stephenfollows82099
I have bought some bright steel to make tool makers clamps. Problem is I can't cut a thread in the stuff. Good quality taps used, correct size holes and even tried oversized holes but no joy. Years of cutting threads but not had this problem before. Steel is dulling new, unused taps.

Anyone had this problem? I have read another post where it was suggested that the holes were the wrong size r the taps were blunt. No so in my case.
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3 May 2023 at 17:28 #29164
Stephen Follows
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@stephenfollows82099
3 May 2023 at 17:37 #643802
Alain Foote
Participant
@alainfoote90915
Stephen are you using a tapping compound e.g. Rocol RTD? Especially helpful if it’s stainless steel or gauge plate etc. What size thread/pitch/thread form? What is the material grade?

Alain
3 May 2023 at 17:53 #643806
SillyOldDuffer
Moderator
@sillyoldduffer
Sounds like work-hardening.

A mistake maybe? Someone thought 'bright' meant a shiny stainless steel was wanted rather than Bright Mild Steel.

If it is a work hardening stainless steel the taps may be blunt now.

Dave
3 May 2023 at 18:19 #643812
Stephen Follows
Participant
@stephenfollows82099
The steel is definitely not stainless. I was trying to tap 5/16" BSF, 24tpi.
3 May 2023 at 18:19 #643813
JasonB
Moderator
@jasonb
HSS tool blanks are also bright and steel, without knowing what you bought its a bit hard to say. Did it saw and drill OK?
3 May 2023 at 18:36 #643817
bernard towers
Participant
@bernardtowers37738
Try the spark test on your bench grinder
3 May 2023 at 18:40 #643819
Clive Brown 1
Participant
@clivebrown1
Doesn't have to be stainless steel to be tough on cutting tools. Steels with a fairly high manganese content can be as well. It's what they make prison-cell window bars from! ( No good smuggling in a hacksaw blade).
3 May 2023 at 19:33 #643830
Dave Halford
Participant
@davehalford22513
Posted by Stephen Follows on 03/05/2023 17:28:49:

I have bought some bright steel to make tool makers clamps.

The above would imply not mild steel, it's a bit bendy, did you tell the supplier what it was for?
3 May 2023 at 19:49 #643835
JasonB
Moderator
@jasonb
Not sure what would imply that the ones I made at school were bright mild steel and still going strong.
3 May 2023 at 21:58 #643855
Stephen Follows
Participant
@stephenfollows82099
Hand cut ok with hacksaw. Milled ok but seemed to be a bit harder than usual to drill.
3 May 2023 at 22:06 #643857
Bill Phinn
Participant
@billphinn90025
Stephen, the way it works is that if you want to know a material's machinability you need to know exactly what it is. "Bright steel" (sic) could be one of countless different steels. "Bright mild steel" would bring us closer, and EN1A, for example, would more or less nail it.

If your supplier didn't give you a code such as EN1A and, what's worse, described it merely as "bright steel", it's impossible to say exactly what it is you're trying to machine and why it's causing you problems.
3 May 2023 at 23:02 #643864
Stephen Follows
Participant
@stephenfollows82099
It’s described as bright mild steel. No numbers.
3 May 2023 at 23:53 #643871
Dave Halford
Participant
@davehalford22513
Posted by JasonB on 03/05/2023 19:49:46:

Not sure what would imply that the ones I made at school were bright mild steel and still going strong.

I made some pliers at school, case hardened jaws and 1/8" handles with a twist near the jaws, they looked great , but boy did they bend .
4 May 2023 at 00:14 #643872
duncan webster 1
Participant
@duncanwebster1
I wouldn't buy any steel without a spec. If it's a ME supplier he bought it from a stockist, so should know what it is. If supplier won't tell you what it is go elsewhere. Good Commercial Quality means they've lost the cert.
4 May 2023 at 00:17 #643873
Bill Phinn
Participant
@billphinn90025
Posted by Stephen Follows on 03/05/2023 23:02:11:

It’s described as bright mild steel. No numbers.

Working on the assumption for now that it should be readily machinable with good quality drills and taps, what are your taps exactly, i.e. brand and type? Are the holes blind or through holes? How deep? Can we see an image of a now dulled tap and a hole it struggled with?

You say you're trying to thread 5/16" BSF x 24 TPI. But 5/16" BSF is 22 TPI.
4 May 2023 at 04:19 #643880
Hopper
Participant
@hopper
Posted by Stephen Follows on 03/05/2023 17:28:49:

I have bought some bright steel to make tool makers clamps. Problem is I can't cut a thread in the stuff. Good quality taps used, correct size holes and even tried oversized holes but no joy. Years of cutting threads but not had this problem before. Steel is dulling new, unused taps.

What brand of taps are you using? Sometimes you get a duff shipment that are not correctly manufactured or heat-treated.

Try drilling and tapping a hole in a piece of known mild steel that you have machined before without problems. If it taps OK, then your problem is the bright steel stock you bought for the toolmakers clamps.
4 May 2023 at 10:08 #643902
Brian Wood
Participant
@brianwood45127
As a suggestion, try heating to a dull red heat and let the material cool as slowly as possible buried in something like vermiculite. That will certainly alter the crystal structure and it might be enough to let you get on with making your clamps

Regards Brian
4 May 2023 at 10:27 #643905
Stephen Follows
Participant
@stephenfollows82099
Apologies, I was initially trying UNF which is 24 tpi. Drilled a new hole After tap ruined and tried BSF.
4 May 2023 at 10:56 #643910
SillyOldDuffer
Moderator
@sillyoldduffer
Posted by Stephen Follows on 04/05/2023 10:27:56:

Apologies, I was initially trying UNF which is 24 tpi. Drilled a new hole After tap ruined and tried BSF.

Easily done! If only there was a single standard system thread system that did away with BA, BSW, USS, UTS, BSF, BSC and others.

Oh there is – metric!

I shall be hiding in my bunker for the rest of the week…

Dave
4 May 2023 at 11:22 #643916
Stephen Follows
Participant
@stephenfollows82099
You're right SillyOldDuffer. Unfortunately, before you know it someone will want to split metric into coarse and fine….
4 May 2023 at 11:28 #643917
Nick Wheeler
Participant
@nickwheeler
Posted by Stephen Follows on 04/05/2023 11:22:03:

You're right SillyOldDuffer. Unfortunately, before you know it someone will want to split metric into coarse and fine….

Let 'em.

You don't have to for your own stuff…
4 May 2023 at 11:28 #643918
Hopper
Participant
@hopper
Posted by Stephen Follows on 04/05/2023 11:22:03:

You're right SillyOldDuffer. Unfortunately, before you know it someone will want to split metric into coarse and fine….

And there are ISO metric threads, DIN metric threads and JIS metric threads…
4 May 2023 at 11:30 #643920
Nick Wheeler
Participant
@nickwheeler
Posted by Hopper on 04/05/2023 11:28:09:

Posted by Stephen Follows on 04/05/2023 11:22:03:

You're right SillyOldDuffer. Unfortunately, before you know it someone will want to split metric into coarse and fine….

And there are ISO metric threads, DIN metric threads and JIS metric threads…

Surely the threads are the same, but less important things like the size of the heads/nuts change?
4 May 2023 at 15:55 #643964
Anonymous
Posted by Nick Wheeler on 04/05/2023 11:30:00

Surely the threads are the same…

Not necessarily; M3x0.6 is used in Japan, and to some extent the US.

Andrew
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