Staff tunring on a Taig lathe

[gerene]

Some time ago I started experimenting in turning balance staffs. I do have a Taig lathe and a Sieg Nano lathe. The Taig lathe is bigger than the Nano lathe but the overall quality is better (I think) and I do have a headstock for WW-collets. The Nano lathe uses either a 3 or 4-jaw chuck and ER11 collets. Obviously the 3 and 4 jaw chuck are not suited for such small items and I was not very happy with the ER11 collets either, since they do not grip in the front of the collet, like ww-collets do.
So I started trying to make very thin staffs with my Taig lathe but was not very succesfull in the beginning. When I arrived at approx. 0.5 mm the staff would break. I was using standard Taig HSS tool bits, which I thought I sharpened and honed sufficiently. Getting frustrated a little bit, I decided to let it be for a while and started to do some research on the internet. I came across an article on the NAWCC forum about turning staffs on a Sherline lathe. My feeling was that when it can be done on a Sherline it should be possible on a Taig, since they are both around the same size. The only difference was that the article suggest using a brazed carbide AR-4 tool.
Today I tried with such a brazed carbide AR-4 tool and indeed I managed to turn a pivot with size 0.09 mm, which would be good for turning watch staffs.
It might be that it can be done with properly sharpened HSS tools as well, but the carbide tool was able to cut the blue pivot steel right away without any sharpening or honing.
I do not have a staff yet, but I am more optimistic in being able to make one some day

Here is a picture of the 0.09mm pivot in the lathe.

Jan

[nic422]

This is ironic. I was going to ask about carbide bits verses high speed steel bits today. I have a Peerless lathe and only have been using high speed steel bits. They seem to work fine on brass, but when trying to mill out a stainless steel bezel, the stainless eats the high speed away fast and does very little cutting on the Stainless. So, along the same lines as the carbide bit you were using, would be great if someone could chime in about which is best on a lathe for blue steel and stainless. Which types of carbide bits are best to buy, ones on eBay, of elsewhere?

Looks nice by the way.

[tmac1956]

Jan:

This looks very impressive. I haven’t even attempted that yet.

Thanks!
Tom

[chris mabbott]

Jan,

I basically went down the same road as you did, I was using HSS blanks, making my own cutter/gravers at various inclusive angles, forming relief lips, honing to a mirror shine, the whole 9 yards, but I had the same problem, the HSS seemed to dull super fast, and I was not heavy handed, I changed bits often, resharpened frequently, but still had rough cuts and had to apply too much pressure when it had been reduced in size..

I changed to the carbide blanks and made my own, MAN what a difference, it cuts through the blued steel like butter, leaves a nice finish, and you don’t need a lot of force on the crucial finishing cuts.

Problem is, you have to retool your grinder with the proper stones to sharpen/form the blanks, if you try it on a regular stone, you’ll heat up the carbide too much.. So it cost me an extra 120 euros for two new grinder stones, and 60 euros for a diamond impregnated bench stone. But the sharpening process goes a lot faster. I was all day with the wet stones and my fingers were bleeding from pressing down 😆

[bernie weishapl]

I use carbide on blue stem steel. Thankfully with my woodturning I replaced my sharpening wheels with 80 grit and 120 grit diamond grinding wheels. They work well with the carbide bits.

[mclark3617]

I have used HSS and carbide both on stainless and they each work well, for small stuff I prefer HSS, carbide seems to work best on bigger things were wear is a factor. You just have to slow down the rpm, remember blue chips are bad, and if you feed too slow you rub more than cut and end up work hardening the stainless. For drilling I prefer HSS, carbide tends to break too easy. With stainless you just want to remember to keep it cool. And don’t work harden it. If it does get work hardened then you may need carbide to break through the work hardened layer. Stainless can be finicky it just take practice. Also stainless is actually a soft gummy steel when cutting and then you factor in the different types of stainless the speeds and feeds are all over the place, so you have to know what your cutting. 300 series is non magnetic and softer, 400 series is magnetic and has more chromium in it, its harder but cuts nicer. That’s the basic stainless, there are more exotic and tougher grades. Hopes this helps

[nic422]

Great info thanks! Just buy any old carbide bits on ebay, or do you recommend a source? Thanks!

[chris mabbott]

I buy mine on ebay, the 2x2x100mm square blanks, or what ever size I need, and grind them into gravers..

But if you’re in the US you can get blanks anywhere

[Author]

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