where does one go.

Where does one go to purchase small round bar (around 33-35mm dia by around 100mm long) suitable for hardening and what type steel should I ask for? need to machine a thread on outside bore the inside then harden it, I then need to heat it up so when its on the shaft and cooled its not coming off. I have contacts via work who purchase steel but supplier only sells large amounts.

Can't help you with a shop for steel. However I think you may be heading for a problem.... Heating the hardened part up to shrink fit it is likely to anneal, or at least soften the part. I would suggest that you consider loctite, if you use the right grade and do it i.a.w. instructions it will not come off....

best of luck

cheers

Bill

Ian, would be helpful if you said where you are located, your prifile can do this, and regarding the material it depends on what the application is, more info needed to offer appropriate advice but there are quite a few suppliers of small quantities of steel, try M-machine metals.

You might find an air hardening tool steel A2 or D2 will fit your application if it is small csa and not critical hardness etc. Both should be available as short cut lengths.

Mark

Good point JohnF will do that as when I have found some material might be asking who's local who has working lathe. (mines in bits). might do sketch of what the application but will have to scan it at work tomorrow.

Thanks Mark C.

I just got 2 3-inch lengths of 2 inch f/c steel from College Engineering Supplies. Their minimum order quantity is 6 inches. Arrived very quickly, 2 days after ordering.

Why does it need to be hardened? If the thread is for fixing, few such threads are hardened. If for adjusting, then hardening will distort it so may lose accuracy (depending on how important that is. CES also stock EN8 and EN24 which are tougher, harder to machine, but could be quite adequate for the job without hardening.

As for fixing, the trouble with shrinking on is getting the dimension just right, and working fast (if you don't heat to high temperature). You start to fit the heated bit which is smaller and has lower thermal capacity, it cools a bit, sticks, and cools down more, before you know it it is stuck fast in the wrong place. You can't shift it because it is very hard to differentially heat the sleeve and shaft. The only times I have used shrink fit, I cooled the inside in the freezer (because it was small enough to go in) and heated the outer with a blowlamp until it was well over 200 C judging by the fact it was just starting to colour - went together OK but cooled and locked very fast, I wouldn't like to try this with a long workpiece unless I could get it nearly red hot.

Much safer to use Loctite! Dimensions not so critical, and you get some time to position the sleeve just right.

Ian have a look at your messages John

Thanks for all the good useful info. I'm on few other car related forums but you guys (and just to be correct girls if there is any) are pretty high on my list already as the best. Any way back to this topic. Just run a file over the spindle and its not as hard as I first thought. Below is picture of the spindle and its easy to see the problem. Now apart from making threaded part to attach to the damaged area (after removing the thread) as someone has mentioned the re-threading of the spindle and making new threaded collar could also work the only problem I see which might not be as bigger problem as I think is how to hold this in a lathe the bearing at the other end is not easy removed without wrecking it and very expensive to replace. Any thoughts appreciated.

Must also add there is chance that I might be able to get second hand spindle from fellow ME member so just pursuing other options as back up plan.

Edited By Ian L2 on 14/12/2014 20:14:30

Ian, you have a personal message

Hi again as fellow member (Swarf Maker) has rightly pointed out that I have not actually mentioned what this is for so just so as not to confuse the item is a lathe spindle.

If you have enough wall thickness to turn off the thread and fit a sleeve then you should definately have enough to just skim off the thread, recut a smaller dia one and make up a new adjusting ring to fit that thread

As for holding it in teh lateh assuming the spindle has a MT taper then hold a blank in the 4-jaw taper poking out , push the spindle onto this and support the other end with a fixed steady while you turn down the end.

J

If you were worried about it working loose then a bit of studing in the MT blank with a washer and nut sticking out teh spindle would hold it tight. Or if you have a large tailstock centre that could be use dinstead of the fixed steady and it won't go anywhere. Yes the actual MT will give enough drive.

There is another man on this forum who would just build up the damaged area with weld and cut a new thread

I would just use a three jaw on the chuck register with some brass shim to protect the latter and the spindle supported close to the threaded portion with a fixed steady.

Ian, did you see the sectional drawing I posted in your other thread?

Russell.

As its the bearing preload nut and there's some meat left in the spindle, I would get the end rethreaded at a smaller diameter and a nut made to fit. It's an easier job as as along as the spindle and nut as the exact thread doesn't matter as long as they match. No worries about concentricity/fit of sleeves etc.

Neil

Ok. Thanks for the replies.

Lucky b***er, good Christmas pressy.

Ian S C