Tiny Vertical Based On G. Britnell's Design

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vtsteam:
I'm wondering, Stewart, if the brass-suitable dies have the same reduced cutting angle that we put on drills and lathe tools for brass? And if so wouldn't that make it hard to cut ferrous metal? Dunno, myself.

edit:
Don't know if this applies at all, but I've been digging through my books, and this caught my eye (from 1924 popular Mechanics book on drilling and thread cutting).

greenie:

--- Quote from: sbwhart on January 10, 2015, 08:27:18 AM ---

Thanks for the tip greenie I've just ordered some off ebay

I must admit I'm having a real problems cutting the M1 thread in these little bolts the first lot I made I made from an old bicycle spoke I had problems with the die ripping the thread the nut only just gets an hold in fact the nuts are dropping off, I've just made some more from stainless steel S303 I was thinking this would be better than the spoke, but again no go, the die I used cut a clean thread on some brass rod but I do have another die that I can try.

I've just got my engineering books out and checked out the major/minor diameters of the nuts and bolts of these little buggers and to be honest there isn't much to play with.

Any suggestions from you guys would be greatly appreciated.

Stew

--- End quote ---

A possibility with the spoke material and the ripping threads, is the quality of the material - like what grade of steel is the material that the spokes are made from ?

There are two cutting edges on a die as well, one side allows the thread to be formed as a taper, the other side is for cutting up to a shoulder, be careful of which side your trying to cut any hard material with.
Have a real close look at the die your using and check out which side is what. Normally the side that has the brand on it, is the 'starting side', BUT, I have other dies that prove that wrong as well.
It all depends on the maker of the die too, the old theory of - "you only gets what you pays for " - is sure going to rear it's ugly head about now.

As for the die cutting too small a thread, what you need is a split die, with these you can push/jamb a piece of ‘whatever’ into the split and force the die cutting edges apart. This will be a bit of a ‘suck it and see’ until you get it just right. What I used was a bit of brass and filed a long slow taper onto it, then tapped it in to the split on the die, cut a thread and tested it with a home made nut, kept tapping this bit of tapered brass into the split and testing, until the thread was just right.
I have cut thousands of 10 BA, 12 BA and 14 BA threads, using the bronzing rod as the preferred material for making miniature coach bolts, using the appropriately sized dies for many years, it's them little bleedin' skinny taps that cost the money, when they roll of the bench and break as they hit the floor. :palm:

Others will have their own 'special tricks dept' for working with stuff that is a bit on the small side, possibly somebody could add some more.

regards greenie

sbwhart:
Thanks for your suggestions Chaps

The die I've been using is from a set of small taps and die that are readily available the dies are not of the split type so I guess they are more like a die nut, its hard to tell even with a strong glass what the cutting angle is and on what size of the die gives the correct lead in, but swapping it round is certainly worth trying. In the mean die I've ordered a split die of eaby, I gave myself a freight when I looked up the cost of dies from a UK trade supplier they ranged from £65 to £90 each :- OUCH.

Strangely enough the spoke material turned up nice better than the 303 even, I figured that for its application it would have to be good quality stuff, and spokes are threaded:- so it points to the problem being with the die.

Cheers and thanks again

Stew

Pete W.:
Hi there, Stew,

Regarding threaded spokes - if you're talking about bicycle spokes, I believe the threads are rolled rather than cut.

Manxmodder:
Hi Stew, you've done some absolutely amazing work on this little engine :bow:

On the threading subject I can second what Pete W is suggesting about spoke threads being rolled. They are done that way because the rolled thread is stronger than a cut one.

In amongst a recent haul of tools I was given there are a couple of old spoke thread rollers and various roll dies,though they have all seen better days.

Below I have linked a YouTube video of a spoke being thread rolled on a Cyclo brand rolling device,these small rollers may be really useful for some of you chaps doing miniature threads.

Hope this helps......OZ.

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