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asalcedo · 07:06 PM

Quote:

Originally Posted by The Other Mike[_3_]

On Fri, 16 Aug 2013 17:21:28 +0200, asalcedo
wrote:

Following up from my previous thread.

I am going to try and tap a 7/32" BSW countersunk screw 10 mm long

I have found the following dies:

'7/32 BSW dies'
(7/32 BSW dies)

'Rotagrip - 04) 7/32 x 24 BSW HSS Die 13/16\" Diameter'
(Rotagrip - 04) 7/32 x 24 BSW HSS Die 13/16" Diameter)

A couple of questions:

1. Which blank can I use?
2. I have a 25mm die holder from a metric tap and die set. Do I need to
get a 13/16" die holder for the dies above?

You can't buy countersink screw 'blanks'

Holding countersink screws and machining a new thread on them is not
straightforward so you need to machine from solid

What you are trying to do requires machine tools not a diestock and a die. At
the very least a lathe, preferably a milling machine as well to cut the slots
for the screw head. Think a minimum of 750 quid, a few months to learn, jigs
to hold the blanks and part machined screws and quite possibly a **** end
product.

A 13/16" die holder is needed for 13/16" diameter dies.

What is wrong with buying the as near as dammit 12 24 UNC screws off the shelf
at 60p a piece?

--

I have indeed ordered the 12 24 UNC screw from the place you pointed me to, a2stainless.com (they have been close for holidays and delivery will be delayed)

But I wanted to give a try as well to making a 7/32 BSW, if it were easy.

So, is it not possible to make the screw using the 7/32 BSW die from a tap and die set starting with an M6 slotted countersunk screw where I had removed the thread and holding it tight on a vice?

Also, and excuse my ignorance, other than to clean a thread or rethread a slightly worn out one, what use are the dies in a tap and die set for?

Thanks.