Thread rolling

[AdeV]

Has anyone here any experience of rolling threads rather than cutting them?

I was thinking of getting a Fettes (maybe) head, and some thread rolls, with a view to making my own cylinder head studs (as ARP want over $1000 for a set); ideal job for the new lathe, but should work fine even with the current machine. Cutting them is an option of course, but rolling them would be better.

So; do thread rollers drive themselves like taps/dies do? Do they try to roll full-depth in one pass, or is it a multi-pass job? Any/all info gratefully received; I'd go YouTube hunting, but it's work time for another couple of hours.

[John Swift]

Hi Ade

the one time I watched a thread being rolled
it reminded me of a Coventry die head with 3 thread form rollers instead of 4 cutters

the rollers are free to rotate like Knurling Rollers and I guess self synchronise the same way

just as with a Coventry die head , the thread roller is advanced slightly less than the thread pitch requires  so the front part of the thread roller mechanism  is pulled forward enough at the end of the thread to trip the mechanism to retract the rollers to enable you  remove the die head or thread roller without reversing the spindle

   John


http://www.threadtools.com/Files/Thread%20rolling%20technical%20info.pdf

http://www.racingvincent.co.uk/14%20Norton%20Site/Manx-Norton-28.htm


ps
with the thread roller in the first pdf the   work piece is driven , the thread is produce in one pass

in this you tube video the rollers are driven -

 

pps

two types of thread rolling on a lathe

[A WELLWISHER]

Hi, I have done a great deal of thread rolling on manual, mechanical automatic lathes & CNC lathes, if as you say the component you wish to produce falls into the obscene price range then rolled rather than cut threads are the way to go, due in large part to causing the lengthwise grain of the bar being deformed to exactly follow the thread form rather than cutting through it like a diehead or single point. However it would help as a starting point if you could say what size & type, manual, centre lathe, capstan lathe to advise on the size of the task you are setting yourself. The work itself is not difficult, but does have certain pitfalls that it is best to be aware of prior to starting out, the laws off physics are in play & do not like to be disrespected! I have taught quite a few people over the years (thread rolling that is) & will be happy to do the same for you.
Cheers A.Wellwisher, retired old bloke

[AdeV]

Hi Wellwisher - let me be the first to welcome you to these excellent forums, hopefully you will enjoy them as thoroughly as I and many others do

OK... to answer your questions:

1) Yep, the price I've been quoted comes close to the "obscene" bracket - $1200-$1700 for a set of head & main studs for a Jaguar engine, in HT steel.
2) The studs are mostly in the 5/16th to 9/16th range, one end is always UNC (thread pitch to suit size), the other end is UNF. Which is why they're a custom manufacture & not easily available off-the-shelf. Even Jaguar don't seem to have any...
3) I have a 6.5" Edgwick manual centre lathe, it's quite worn, but would almost certainly be capable of providing the force necessary to roll threads. I'm not sure if the tailstock bearing will take the strain, it's badly worn & as yet I've not got a Round Tuit to fix it... although I do have a spare tailstock (bearing in as-yet undetermined condition).
4) CNC lathe (which I haven't got yet... and is in unknown condition) is a Mazak Quickslant 20. With a 22KW spindle, I don't think I'll run out of horsepower, although I might melt the supply cable trying to get there... It's a twin-turret (4-axis) with tailstock. As far as I am aware, it doesn't support live tooling, but I might be wrong there.

For the application (engine head retaining studs on an engine I intend to rev rather higher than production), I'm pretty sure rolled threads will be far superior to cut threads... and I presume that's how Jaguar did it.

[Jonny]

Ade which engine is it and year, think stealer taking you for a ride adding a zero to the end.
Dearest found so far but in US $14.09 each genuine.

Failing that do have two contacts at main JLR.

[AdeV]

Ade which engine is it and year, think stealer taking you for a ride adding a zero to the end.
Dearest found so far but in US $14.09 each genuine.

Failing that do have two contacts at main JLR.

Hi Jonny,

It's a 1977 5.3 V12 - I also need big & little end bearings, and it'd be kinda handy to have a set of dizzy drive bearings as well...

The $1200+ quote is for custom made studs from ARP.

[Jonny]

Ade many different lengths of stud for the V12 but suspect part C32679 £12 ea.
Have a butchers here http://xjkltd.co.uk/

[chipenter]

Have you tried Manners they had all the bits for my Daimler 250 restoration http://www.jagspares.co.uk/Manners/partdetailalternate.asp?partno=C32680* .

[AdeV]

Thanks Jeff - I haven't, but I certainly will be come the new year! I'm currently making space for the new lathe, but I think it'll be cheaper to buy a set of studs, than buy the thread rolling head & learning how to use it... the first time at least...