MadModder

Gallery, Projects and General => How do I?? => Topic started by: Chazz on April 22, 2011, 09:08:23 PM

Title: To Heat Treat or not?
Post by: Chazz on April 22, 2011, 09:08:23 PM

I just completed making my new cross-slide screw for the 9 x 20, it's O1 Drill Rod (anealed state), 7\16" Dia x 20 TPI.  The thread is 5\8" longer than the stock screw as well.  The new cross-slide nut is made from zink-infused key stock.

Given that it fits, it's straight and works great and having only heat treated a couple of things before, I'm concerned about the diameter to length ratio and controlling distortion.

A check of Machinerys pointed me to 'nitriding' so I made a couple of phone calls and the best price I could find in my neck of the woods was about $100.00 CDN including return postage.

Is this a reasonable price?  I know I'd have to give the thread another skim to allow for the treatment.  Anyone here have experience with this process?

Thanks,
Chazz

Title: Re: To Heat Treat or not?
Post by: Bernd on April 23, 2011, 08:40:57 AM

Chazz,

Save your money. Personal opinion, I'd say O1 will be hard enough for what your doing.

I think if you took a file to your old cross screw you'd find that the file will leave a mark because it isn't hardened.

Bernd

Title: Re: To Heat Treat or not?
Post by: doubleboost on April 23, 2011, 04:54:57 PM

I would leave it as it is
I have made lead screws with silver steel un hardend and they have been fine

Title: Re: To Heat Treat or not?
Post by: Chazz on April 24, 2011, 02:06:38 PM

Bernd- Save my money?  :lol:  Is there really such a thing in this hobby? I'm like the government, continual budget reallocation and convincing the voters (think Missus) that a QCTP is far, far more important than getting the dead lawnmower fixed.  :thumbup:

doubleboost  - I concur, I will leave it as it is for now and check for (my concern) galling between the nut and screw.

Tnx ,
Chazz

Title: Re: To Heat Treat or not?
Post by: DaveH on April 24, 2011, 03:35:08 PM

Just for interest I have had quite a few items nitrided.

The dimensional change is negligible and I have never noticed any distortion.
However I have always used a special steel specifically for nitriding which is normalised and annealed then hardened and tempered before use.

Just a comment


DaveH

Title: Re: To Heat Treat or not?
Post by: bilhar on April 26, 2011, 03:37:51 PM

o1 tool steel is not suitable for nitriding it will embrittle the steel without any appreciable hardening.    For suitable nitriding  steel the steel needs to contain few percent aluminium and/or chromium for nitriding to work.      the process involve heating 500deg C in a atmosphere of ammonia for period of time which determine the depth.

over night ie 12 hours at temp gives around 0.005" deep 48hours 0.012"  96hours 0.020"
just incase any one is interested