Stainless steel spindles

[DCBluesman]

I overheard a conversation at Woodcraft the other day, but the customer got away before I could get any details. He was talking about a source for stainless steel "A" and "B" spindles for the MT2 mandrel. Does anyone know a source for these?

 

[Fred in NC]

Never heard of them, Lou. Did the customer mention the advantage of SS over drill rod, which is the usual material for the shafts?

 

[wayneis]

He may have been talking about the MT part not the shaft. Stainless may be a better steel for that? I have heard of a few people getting their mandrel stuck so bad they almost wreaked the lathe getting it out.

Wayne

 

[btboone]

I made my own spindles for my CNC lathe from letter D (.246") ground rod from MSC Industrial Supply. I used air hardening steel, but they have stainless too. You just drill it it with a centerdrill for centering on the live center.

 

[Fred in NC]

Bruce, I assume you threaded the end too. Also, that you are using a collet at the spindle end. Is that right ?

 

[btboone]

Hi Fred, Yes, it is threaded with a 1/4-28 thread. I did make a holder from 1 1/4" titanium with setscrews and a step that steps it down to 1" diameter. I can throw it in the lathe and bottom it out on my chuck (which is set up for 1" diameter stock) and know exactly where my zero point is. I have it short enough to do either half on a normal pen and a nut locks it in place. The nut was turned as if it were pen material, so no spacers or washers were needed. My tailstock is manual, but has a hydraulic quill, so it keeps constant pressure on the mandrel when it spins.

 

[Mac In Oak Ridge]

Holy Mackerel Bruce. That sounds like a space age pen holder. Cool!

 

[DCBluesman]

I didn't get a lot of the conversation as I really wasn't eavesdropping, but this guy was saying that there is less "play" in the stainless steel spindle. I must say, though, the idea of stainless for the MT end sounds like it would REALLY help.

 

[btboone]

Hmm. Shouldn't make a difference in the material. The stuff I have is dead on size and is mirror finish. Getting the exact diameter is the trick. Drill stock is great in that it's also about $2 for 3 feet of it. You can calibrate your calipers with it too.

Mac, the titanium stock is something I have lying around the shop. It's great in that it is hard and doesn't corrode. If I happened to have stainless or brass, I would probably have used them just the same. The trick for me is to not have to figure out where the zero point is. I can throw in the mandrel and throw on any material and push the button and get a good part without all the setup time. The manufacturing engineer in me is always striving to cut out unnecessary steps.

 

[Mac In Oak Ridge]

Bruce, I gather from your comments and web site that you have a decent machine shop at your disposal. Perhaps you need to consider marketing your design. Other pen turners may just like it.

 

[btboone]

Hi Mac, yup. I have a pretty nice setup. Check out the Welcome page for a bio. I'm the one from Roswell, GA.

I would be able to make the mandrels. I guess most wood lathes have a #2 Morse taper at the headstock? I would need to get dimensions of what's needed, but it would be doable.

 

[Fred in NC]

Bruce, I might get flamed for this!

For high precision work on small diameter spindles, machine shops use a collet instead of a chuck. A collet based mandrel has the advantage that there are only two operations needed on a shaft of the proper diameter (size D drill rod) 1. Thread the end for the nut. 2. Center drill the end for the 60 deg. live center. Of course, the edge of the opposite end can be eased, or rounded slightly for ease of insertion into the collet.

The outside of the collet itself, of course, would fit the Morse taper.

This type of mandrel, complete with collet, is availabe for about $26. I am not sure about the accuracy of the collet itself.

I use the Woodcraft $10 mandrels myself. The Morse taper has a deep hole, and the shaft threads at the end of the hole. They seem to run true, I tested mine with a dial indicator. I bought an extra shaft just in case.

Just my $.0002. Close tolerance, eh ?

 

[btboone]

No Flames, heck, no sparks either. That sounds like a better way to go. The collet takes up any side to side play that a setscrew type setup can get, and should be more easily adjustable. I did mine so it was almost a press fit, which kind of makes adjustment tricky. The setscrews would also gouge the rod, so it would be even harder to move. Good thing I shouldn't have to move mine. []

 

[Fred in NC]

Bruce, there is an improvement I would like to see in a shaft for use with collets. It is a collar near the collet end. I have seen some that look like a pressure fitting, but the face does not run true. A machined collar near one end would allow me to turn a pen, apply some finish, and take it off the collet and set aside to dry, while I work on another set of barrels.

Currently I just use several mandrels with attached Morse tapers, and take the whole thing off the lathe. Removing and reinstalling the barrels on the mandrels does not assure exact repositioning. Causes problems in sanding and finishing.

Maybe you can come up with a better system! I hope so.

 

[btboone]

Hi Fred, I'm not sure if you're describing the drill stop collars that I've seen, but those should work. They are a round disk of metal, maybe 3/4" diameter by 3/8" tall with a hole, say 1/4" going through it. The part is split and a socket head machine screw tightens the split part together. If the face of one of those isn't true, you can turn the face on your lathe.

 

[jwoodwright]

Fred,
I have a #2MT Drill Driver from Berea. I have several mandrells also. The Drill Driver stays in the Headstock and the mandrell slips out. The barrels remain in position...
Loosen the tailstock, slip out the mandrell, load new mandrell, tighten tailstock... 10 seconds![]