|John Burridge||20/04/2014 11:56:07|
|54 forum posts|
I have been tasked by SHMBO to restore a brass bed which she picked up for nothing.
The bed is screwed together with unusual threads ie: 1/4" X 22TPI thread(5/16" X 22 TPI being BSF) both left hand and right hand.
I have some of the screws and nuts missing and have made some studding by screw cutting the nuts I need to tap.
I have searched the internet for non standard threads and even Tracy tools don't keep this size in right hand nor left hand and the price is prohibitive to have some specially made.
So I have thought about making taps and then making a die.
When I have usually made taps and dies I have used silver steel and gauge plate.
What material do other model engineers make there taps and dies out of.
I have made taps at work out of HSS but don't have the heat treatment plant that I once had available, So do I use another material which I can harden but also have a good tough core strength which is hard to achieve with the standard silver steel.
I could case harden and this would probably do the job after I have cut the flutes in the tap.
|Tony Pratt 1||20/04/2014 12:21:31|
|959 forum posts|
I'm pretty sure silver steel is the DIY metal of choice for taps & dies, when you think about it all the commercial taps etc are through hardened as can be testified when you snap one! I would say O1 is better if you can heat treat it?
|Gerald Howarth||20/04/2014 12:39:52|
|2 forum posts|
There was a conversation on Practical Machinist I saw about this subject - may be of interest. Google 'home made taps' and a the Practical Machinist reference is right there, the method seems strange but may be of interest to you.
|colin hawes||21/04/2014 15:16:33|
|502 forum posts|
Old files can provide a good source of tool steel cut up with an angle grinder and annealed. Some types of spring steel can also be annealed and used for making cutting tools. I've used both but once tried to use an old spring that I simply could not get into an annealed state. K.E. 595 and 672 are also very tough tool steels and are used for press tools. Colin
|103 forum posts|
I know this is too obvious but why can't you just make it a different bigger thread. Like 5/16 BSF?
|thomas oliver 2||21/04/2014 19:58:09|
|104 forum posts|
The American ASME 16-22 is a 22 TPI thread which should measure 0.268ins. near to your thread. Since male thread are usually a few thou.down on nominal size, could this be it?
A comprehensive reference for thread sizes and types can be obtained from www.watchman.dsl.pipex.com
|julian atkins||21/04/2014 22:29:27|
1221 forum posts
i think DMR's suggestion is excellent.
it isnt like you are restoring an expensive antique clock etc.
|Les Riley||10/12/2019 14:51:50|
2 forum posts
Sorry to drag up an old thread but I have just tried to acces the link www.watchman.dsl.pipex.com , which I have used several times over the years, and it has been shut down.
Does anyone know if the chart has been put up somewhere else please?
|Pete Rimmer||10/12/2019 22:44:42|
|536 forum posts|
Luckily for you, someone has archived the site on the wayback machine:
|David Taylor 4||11/12/2019 03:17:58|
|23 forum posts|
I have made several taps and dies using silver steel,(drill rod for USA), with success. Heat treated to mid straw tempering colour. They cut brass well but steel a little less so. Sizes from 16 BA up to .125" two start lh hand square thread. Go for it
|Les Riley||11/12/2019 09:12:22|
2 forum posts
Thanks very much Pete, now saved on my computer!
|1380 forum posts|
From the same linked site:
These are a few photos of my lathe toolpost which is fitted to my Harrison L6 lathe. It is home made and provides a much more rigid mounting for tools than any commercial toolpost I have experienced. It has the advantages of ease of construction, accurate adjustment both for height and angle and is inexpensive to make. It is also possible to make a number of interchangeable tool blocks in which tools could be left set at their appropriate heights.
Does anyone know how to view the photos which are just empty rectangles in Firefox?
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