Why is skiving not used more frequently

I get the impression that not many people use this technique - only a couple of videos on youtube and not much in forums and blogs.

It seems like a terrific idea to me ........ why is it not popular ?

Bill

Edited By John Stevenson on 19/10/2016 13:07:28

Never had the need for it myself, all the profiles I have done have been OK with a form tool mounted horizontally or just not worth the effort of making the tool for a one off that can be done in other ways

As Jason says lot of effort to make a tool for a specific size that may only be used once.

Here is Sandvik's introduction to the process. **LINK**

Martin

For anyone who does not know what Skiving (in metalworking terms) is, then there was an article in an early issue of MEW, using the method for producing a Morse taper. If you have issue 27 then it is on page 51. To my knowledge it is the only article in MEW relating to the method.

Harold

Probably because its a form tool process so for aynthing other than simply producing a basic round part you need to understand how to shape the tool to derive the final part exactly to shape and have the wherewithal to make that tool. Not really something profitable for the average home shop guy to get into. Indeed a lot of production shops who really could have exploited the technique avoided it as being to difficult.

Even for simple shafts its a bit tricky on a conventional lathe because the machine is not made to easily hold and set up the tool. Don't forget that, unlike a conventional radial approach tool changing cut and final diameter is not quite as simple as simply turning the feed handle. You also can't turn direct to square shoulders.

On the right work its very effective tho'. Used to know a man who had an EMI-Mec plugboard auto set up for skiving spindles from round bar stock. Made good money on these simple jobs as they ran very fast. Once you are familiar with it setting simple work up to stops jobs on a plug-board is easy. Reliable too. he reckoned that CNC, screw machine and conventional capstan shops couldn't get near his prices.

Clive

I got asked this at the recent Forncett model engineers day with respect to the valve rod couplers that I'd profiled with the hydraulic copy unit. Since I didn't know what the technique was I couldn't give a considered answer. Having looked on utube I can't say I was much the wiser. I see how the Sandvik process linked above works, but I still don't see how it would help me to cut a multiple curve profile on a conventional lathe? At least not without a whole load more work than making a flat template for the copier.

Andrew

I've only heard of skiving as the process to remove the inner or outer layers from hydraulic hoses prior to fitting the hose couplings. Can't imagine the metal process having much relevance to any of us, given that we can achieve much the same results with more conventional machinery. Great question to ask some metalworking smartass down the pub if you want to shut them up, I imagine.

And of course I have a strong professional interest in the more general art....

Gee Muzzer

What an OH&S nightmare, imagine what that little do dad could do to a hand that slipped into it.

Regards
John

I think the answer is the shortage of jobs actually suited to it. Most skiving needs either a soft material or a lot of power - I'd only come across it as a way of shaping wooden mouldings with a contoured blade before.

Neil

The nearest I;v heard to that is forcing a hardened steel ball through a bore.

The skiving I know of is cutting a low angle chamfer on the in the ends of a leather strap for joining it flush.

Ian S C

There's a video here, interesting stuff

I've had a quick read of the article mentioned by Harold. I now see how skiving works for straight and plain tapers. However, the key sentence in the article says that the work should be roughed pretty much to size before the final skiving. When I made my valve rod couplers there was a significant amount of material to remove to get the final profile, more than ¼" off the radius in the worst case. If one has gone to the trouble to rough out the profile to within a few thou, one might as well continue and finish the item. So I don't really see how skiving was relevant to my valve rod couplers.

Andrew

It does look a lot of extra effort for questionable returns.

It does remind me, however, of the finishing tool like a D-bit turned through ~70-80 degrees that supposedly can remove 'cobwebs' of metal.

Neil

Neil,

Ironically, I usually get a superb finish using that tool, even on cruddy "black bar". I know it as a "vertical shear tool" or a "shear tool" - well documented here http://www.gadgetbuilder.com/VerticalShearBit.html

It removes cuttings as fine as steel wool - quite amazing - it was my first ever succesful tool grind.

To date I have been completely unable to get a good finish with the standard round end HSS tool bit.

I usually get a good finish if I turn a knife tool around to almost rub - as mentioned by Sparey and Westbury in their books - I can also get a good finish if I turn a tangential tool around by 90 degrees to turn it into a shear tool, or put a big radius on the cutting corner, but a conventional round grind HSS bit - never worked for me.

......... and thanks very much to everyone for all the replies on the skiving.

This is called gear skiving and I think it is amazing ............ https://www.youtube.com/watch?v=XUDkQQJ8Uyw there are various other videos on youtube.

Bill

Not sure which thread to post this in but it seems to combine skiving and gear cutting.

Good grief, makes my 'efforts' look amateurish.

Andrew

It's always nice to look at different methods of making things but i think this is a process solely reserved for industrial purposes and not a realistic approach to turning in a home workshop, it certainly does the job but it's not a versatile tool to be had.

Michael W

Edited By Michael Walters on 20/10/2016 21:27:18