Holding steel rod for threading

[Dangermouse]

So what is the rods going to be used for?

 

[Tinbasher]

Have you filed or ground a slight taper to get you started? Starting a big thread without one is very difficult you can always cut it off when finished.

Also assumming you are using "proper" dies make sure the central grub screw is screwed well in to open the die as far as possible. Threading this size with a fixed die or die nut is not impossible but very difficult and will need a fair taper o start.

 

[marcus]

Thanks for these hints, very helpful.

Just wondering, assuming the die is Ok (it seems reasonable quality) how long can I expect it to last before replacing? Just wondering if I should order more to finish this job.

 

[graduate_owner]

I find sandwiching the rod between 2 pieces of wood or ply in the vice works well, as has been suggested, but you don't need to cut notches as the wood will deform and crush with the pressure. It works for me anyway.

K

 

[Tinbasher]

If you are lubricating it it will last out your lifetime BUT they can break especially in the bigger sizes so if the job is time constrained a spare might be a good idea.

I expect you know this but for every 2 cutting strokes you should do a 1/2 back stroke to break the swarf. If you don't the swarf can bind the die.

Traditionally the best lube for steel is Tallow but any cutting or light oil will do. Tallow is less messy but less available these days.

 

[Steve Maskery]

Please indulge a a metal numpty.
Why is it more difficult to cut a big thread over a smaller one? Is is just the increased depth of the thread, the reduced mechanical advantage of the stock, or is there something I am missing? I didn't realise it made so much difference.

Steve, an M6 kind of guy.

 

[jasonB]

Its not so much cutting a bigger thread that is any harder, it is cutting the coarser pitch that is usually associated with it as you are taking a larger amount of metal off per turn of the diestock.

A M20x1 thread would be a lot easier to cut than the Standard metric coarse thread M20x2.5

Same as any cutting opperation really the bigger the amount you remove in one go the more effort required

J

 

[Steve Maskery]

Thank you
S

 

[Tinbasher]

Wot Jason said

Maybe we do need a metalworking section?

 

[Eric The Viking]

Marcus, are you lubricating it?
In my experience it makes a huge difference, both to the effort required and to the quality of the finished thread.

http://www.ebay.co.uk/itm/271113695168

Price £18 (incl. delivery). Worth every penny, and I'm still on the same (red) tin I bought in the 1980s!

E.

 

[Racers]

Hi, Eric

I use EP90 as its in a handy place for taping and my motorbike chain.

Pete

 

[nanscombe]

I remember brushing on cutting fluid that was like milk in the metalwork shop at school in the 1970s.

How come I didn't appreciate doing that sort of thing whilst I could?

 

[xy mosian]

Ah Trefolex. Once you have sampled the aroma you will never forget it. Particularly if you work hard enough to get it warm.
xy

 

[Eric The Viking]

I quite like the smell actually. But it's a right so-and-so to get the last traces off your hands. Forget any idea of the delicate aroma of lunch afterwards!

 

[marcus]

Finished at last! Made use of lots of the advice here, and a couple of ideas of my own. I ended up doing it at my woodworking bench; I don't like doing metal work at it really, but it has a better vise and also a corner which enabled me to walk round as I turned the die which made it easier. I also attached an oak block with a 20mm hole to the stock with hose clips which made starting much easier and ensured the die went on straight (my stock doesn't have a centring device). The swarf just got pushed out the top, it didn't seem to cause a problem. I used thick cutting oil which helped. I also padded the handles with cloth and duct tape to save my hands. Glad that's over! In retrospect it would probably have been cost effective to have paid someone with the relevant machines to do it for me, but quite satisfying to have done it myself....

 

[DTR]

I also attached an oak block with a 20mm hole to the stock with hose clips which made starting much easier and ensured the die went on straight

Clever =D> ... I did the same thing recently in order to bore a straight hole with a brace and bit, but I never thought of doing the same for thread cutting

 

[Tinbasher]

Well done Marcus