Saturday, July 23, 2011

Tempering, aligning, and testing

Had a couple of hours in the shop while my dearest was out for her visitation in NUH as a church volunteer. Few things I would like to try out after reading and playing with the ideas in my mind.

First, is to make a center with straight shank - to be used with the ER16 collet. This was also my first time trying my hand at tempering steel.

I cut off a short section of 10mm steel rod and turn it down a little to descale it. The compound slide was set to an angle of 30-degree to allow an included angle of 60-degree.

After cleaning up with sandpaper, I heated the business end of the center with the Proxxon torch. This torch was bought quite a while back from Mike. So far it has only been used to burn some irritating black ants in the kitchen. I didn't manage to get it cherry red as described in some forum postings. Still went ahead to dunk it in a cup of water when I saw the change in colour.

Somehow, I like the darkish colour...

Tested it by using it to align the A2Z adjustable tailstock with a dead center mounted, a painful process but I managed.

The reason for this adjustable one is the drooping of the original tailstock when extended. I'll work on the repair I saw on the web when I have time.

With some time more to burn, I decided to test out the "follower rest"; using the A2Z QCTP and a brass finger mounted. The brass finger was taken from the fixed steady.

It didn't work as i thought it would. I experienced lots of chatter leaving ugly finishes on the stainless steel pin. The diameter was still bigger at the tailstock end though alignment on both end were done.

I'm hoping that this will not be the result I get from using the Sherline's follower rest, which I should be receiving on the 26th this month. The DRO kit and some other items I ordered should be in the same shipment of there is no screw up.

A bigger lathe is still haunting me. It's now seems that the Proxxon PD400 is the right one to go for. The Wabeco D4000E is my dream machine but the price is too daunting; it is quite a few thousands more than the PD400 but with slightly shorter bed 350mm vs 400mm.

With that being decided, The problem left is, how will I be able to smuggle it into my shop without being seen? Not an easy task as the PD400 is quite big to simple hide away from sight. Besides, the bright yellow (splash guard and chips collection tray) and green would stand out from the Sherline lathe and 2 mills, which are black. Sigh...

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Anonymous said...

Wong, on the center I'm not sure if you were able to actually get it hard. Did you test with a file? Press a fine file on it and try to move it. If it 'bites' in and starts to file off material it not hard. When properly hardened the file will slide over the part and not cut, they call this 'glass hard'. Then it will need to be annealed at a lower temperature to soften but not too much.
When you have trouble getting the part hot enough just put it on a cooking burner first to pre-heat and then use the torch to get it hotter before quenching. Also get a bigger Metal container for your quench can. Plastic can melt and spill the water, and if you are using oil it would really be a mess.

Wongster said...

GeneK, you're right. The center isn't hard enough. I pressed the file down and pushed, revealing "fresh" metal. I'll play with this again when I've time.

I received the tailstock extension yesterday. It looks am easy piece to make at home but I'm still not adventurous enough to turn tapers; more so internal ones. Mounted it on the A2Z adjustable tailstock and the problem of the cross slide running into it is no more. I'm really happy with this.

Will be work on installing the DRO on the lathe soon, hopefully this coming Saturday (tomorrow). I was scheduled on duty on Sunday full day.

Really love your input. Please keep them coming.