Turning very thin bar

[NJHParticipant @njh]

Hi Tel

 

That’s just the item (from Chronos) I was refering to in my earlier post – yours looks rather more robust. Agreed a bit fiddly to set up but, as you say, once set you can churn out long lengths of little stuff with ease. I don’t use it all that often but recently had need of some long 8BA studs. No bar the right size so made a bush and spent a bit of time to get it right for the first one. The rest were like shelling peas!

 

Cheers

 

Norman

Edited By NJH on 31/12/2011 11:08:14

[Chris GunnParticipant @chrisgunn36534]

The other tool we used to use to turn long thin diameters is a roller box, it is a similiar principle as the tools described above, but uses 2 small rollers to support the work, and a tool to do the cutting, all set at 120 degrees apart, and all on adjustable slides. I used these on capstan lathes in the turret, but they could be used in a tailstock. there is no need to make any bushes with this tool, as every element is adjustable. you often see these on secondhand tool stalls, for a couple of quid, and all you need is to adapt the shank to suit your tailstock.

Chris Gunn

[Jeff DaymanParticipant @jeffdayman43397]

A box tool or roller box can be set up very quickly by using a pin or rod of the exact size to be cut. Withdraw the tool in the box. Find such a pin or rod (drill shanks also useful) and put in the bush or rollers. Move the tool up to just touch the pin diameter and lock tool down. Remove pin, place box tool on centre in toolholder. That’s it.

 

JD

 

PS what does all the wheezing and moaning about rising air, common sense, statistics, carbides, and oil in boilers have to do with turning thin long dias?

 

If you want to moan about the air, sense, stats, carbides, or oil, start a new thread! (they are cheap to start)

[Terry LaneParticipant @terrylane]

Yeah Norm, I made mine in 1994 and its probably only been used a dozen time since, but when it is ……

[Sub MandrelParticipant @submandrel]

I had an article on a Box Tool published in ME ion about 2002. An update on one by a chap called Downey in about 1952. It’s a lot less fiddly to set up, but you are more limited as to the length of work.

 

Neil

[john jennings 1Participant @johnjennings1]

Tubal Cain in his book “Simple Workshop devices describes making a set of RoseBits or Hollow Mills derived in part from clockmaking devices for making . screw blanks Essentially they are four toothed end mills with a central hole the desired diameter. They cut on the end only and of course a one size only device. Providing they and the stock to be reduced are both held in accurate chucks alignment should not be a problem. The length of the reduced diameter is not unlimited.

The Jacot tool mentioned previously is more of a filing and burnishing rest than a fixed/travelling steady for turning.

John

[mgjParticipant @mgj]

Sounds like I need to be a bit more determined about using mine.

 

The other option is to build in a bigger scale????

[Terry LaneParticipant @terrylane]

Yeah John, I read about rose bits some time back in the 80’s – probably either Tubal or LBSC – made up a few in common sizes (still have ’em) but don’t like ’em as much as the box tool.

[BazyleParticipant @bazyle]

I have had another thought on this one.
Place a support bar in rear toolpost or equivalent packing, possibly with horizontal groove at the end.
Move in to touch the work.
Rotate topslide to be parallel to cross slide.
Position tool just ahead of this bar and advance the toplide so the tool touches the work.
Move the saddle to clear the tool from the work and retract cross slide by 1 thou (towards you) so the bar comes 1 thou closer to centerline.
Advance the topslide by 1 thou to compensate for the cross slide movement and another thou for the cut.
For each pass the topslide is moved double the support bar movement so they stay in sync wrt the centerline.
It is basicly an easily and finely adjustable travelling steady made from what you already have on the lathe.
The support bar could have a rolling bearing on the end so it could be made easily out of a single point knurling tool.

[jason udallParticipant @jasonudall57142]

one problem with these ” box tools”
They copy the incoming stocks variation onto finished diameter.
Thats part off why sliding head machines use ground stock.
Once had to turn 6.5 to 1.2 mm taper over 150mm.
So far so good.
Stock was Nominally 6.8mm 0.8 mm hole down middle “sort of”
And worst.stuff was poly ureathane..you could tie it in knots….

[jason udallParticipant @jasonudall57142]

any way back to original post.
Like the first reply said… SHARP TOOLS
HSS for when carbide just wont do…!
Oh any cut SS very aggressivly…get under skin and dont let it work harden.
Odds is you ‘rod’ is wire and drawn thus work hardened…sugest starting from larger stock and turning off outside to get at tamer metal. Say start at three mm big.

[SpringbokParticipant @springbok]

Why not just purchase the correct size rod in the first place !!!

Thought

 

bob

[Terry LaneParticipant @terrylane]

‘cos the job is a short section of 0.070″ turned on the end of a bit of 3/32″ rod – presumably the tail on a valve spindle, or some such. (post#1)

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