Annealing ball screws?

[LeeWay]

I asked this on my build log for the lathe, but haven't got an answer yet. Thought this would be a good place to stick it. I have turned my first set of ball screws for my router using a minilathe. I need to turn some journals on two new screws for a new lathe project and I want to make it less difficult, so i want to anneal the ends first. The new lathe will have a setup for a grinder, but the minilathe doesn't. That would be my other option if that were the case.
I am wondering if a MAPP gas torch will anneal the ends of the screws?
I don't have anything yet but propane torches and I cut with a plasma cutter. I have used O2 with propane for a cutting torch before. I have never had any dealings with MAPP gas though. I saw a little torch set the other day that came with O2 as well and was wondering if anyone knows if it will anneal the screws.
TIA.

[orbyog]

I have done them with mapp gas just takes awhile (10-20min for a 3/4" screw). I put the screw in the lathe on a slow speed and ran the flame across untill it was pretty much red hot (the black finish screws get a whiteish hase to them) then let them cool over night (do not water cool ) then they cut just fine.

[LeeWay]

Actually I think I have found the answer. I was looking for the actual temps that these gases are able to produce. Mcmaster Carr had those listed both with and without O2.
I also found this link.
http://www.efunda.com/processes/heat.../annealing.cfm
It shows different ways of annealing.
I think I can handle it from here, but if anyone has any pointers or have done it before, please feel free to comment. Thanks.




Thanks for that.

[kawazuki]

Do do you plan to prevent the heat travelling into / down the screw potentially removing the temper away from where you are cutting?
And re-tempering ? Don't even consider it with steel that is finish machined!

[LeeWay]

I did one last night and then turned it down today. I used a drenching wet rag and kept it wet wrapped tightly around the screw. I heated for about 20 minutes with just a propane torch. The surface did turn kinda powdery light colored. It turned very nicely and I could certainly tell exactly where it wasn't heated. The very last thread was hard.

These are going on a lathe and the first few inches of screw past the journals would never get used anyway, but it worked out great.

[Andre' B]

Ideally you find a friend who has access to one of these where they work.

YouTube - Induction Heating

YouTube - Induction Heating

[LeeWay]

Now that would sure beat holding that propane torch. I didn't get mine red hot, but that wasn't needed to soften it up some to be able to easily turn on the mini lathe. Much nicer turning than my first machines screws.

Here is the result of the first one.