Coventry Die Head

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Coventry Die Head

This topic has 20 replies, 13 voices, and was last updated 30 March 2023 at 17:22 by William Howcroft.

Viewing 21 posts - 1 through 21 (of 21 total)

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27 March 2023 at 16:00 #639283
Chris Crew
Participant
@chriscrew66644
After watching the MrCrispin Coventry die head video on YouTube I decided one might be a novel addition to my workshop. I found the items advertised on eBay and put several in my watch list. One was for a job-lot of three for which it stated they all appeared to work and I received an offer price. I was actually going to reject this offer and the items but, being a weak-willed and spineless character, I pressed the accept button. However, I may have to wear the donkey's ears for a couple of weeks because when the items arrived none of them appear work and all of them will need some remedial work to a lesser or greater extent, or so it appears given a cursory 'once-over'.

So, the questions are these: does anyone have an exploded diagram of one of these devices, is there any company in existence that can supply parts (apart from the chasers which appear to be easily sourced) because I assume these devices have not been manufactured since Alfred Herbert's demise and has anyone else refurbished one of these devices before and could provide some advice?

I am hoping that I can salvage at least one working die-head from the three almost identical ones that I bought and put the rest down to experience.
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27 March 2023 at 16:00 #34195
Chris Crew
Participant
@chriscrew66644
27 March 2023 at 16:29 #639288
Anonymous
Wiseman Threading Tools do a wide range of spares.

Wiseman

Andrew
27 March 2023 at 17:08 #639290
Rob McSweeney
Participant
@robmcsweeney81205
"The Book of the Coventry Diehead" has all the info. There is a downloadable version online somewhere.
27 March 2023 at 17:28 #639292
bernard towers
Participant
@bernardtowers37738
Best of luck Chris your problems are only just starting, wait till you start collecting die sets,I hate to think how much I spent. Good thing to make for them is the internal stop which is a must when making batches of Bolt/Screws. I have just made a batch of 5mm sq headed bolts and they were threaded at 300rpm and the head clicks off at the came place every time,Magic. Thoroughly recommend the book Rob mentioned.

Edited By bernard towers on 27/03/2023 17:29:30
27 March 2023 at 17:31 #639293
noel shelley
Participant
@noelshelley55608
Hi Chris, What sizes and types have you got ? Rob has mentioned the book, it comes in many editions I think mine is ed 25. Noel.
27 March 2023 at 17:39 #639295
Chris Crew
Participant
@chriscrew66644
Noel, They were sold as being 1/2", not sure if this is correct as I am new to this type of device and until I acquire the book/manual I have no idea from where this dimension is taken. Many thanks to all for the responses, thus far.
27 March 2023 at 17:53 #639299
Tony Pratt 1
Participant
@tonypratt1
Chris, were they sold as 'working'?, if they don't work send the lot back at the sellers expense.

Tony
27 March 2023 at 17:56 #639301
Oldiron
Participant
@oldiron
Chris you have a PM

regards
27 March 2023 at 18:55 #639312
Chris Crew
Participant
@chriscrew66644
Posted by Tony Pratt 1 on 27/03/2023 17:53:42:

Chris, were they sold as 'working'?, if they don't work send the lot back at the sellers expense.

Tony

Tony, unfortunately the seller stated 'no returns accepted'. I knew it was punt when I purchased the items, fortunately I elected to use PayPal's 'Pay-in-Three' facility so the financial damage has been spread. At least it has presented me with a challenge to sort out the issues, I actually enjoy repairing and refurbishing bits and pieces so I will now view my purchase as a project.
27 March 2023 at 19:19 #639315
peak4
Participant
@peak4
This Site may have some useful info as well
https://www.turbinejon.com/technical-data/

Bill
27 March 2023 at 20:50 #639339
bernard towers
Participant
@bernardtowers37738
Usually if its a 1/2' head that's the max size thread dia, although in later years oversize sets were available.
27 March 2023 at 20:51 #639340
Oldiron
Participant
@oldiron
Chris. The seller can say "no returns" but if you report to YT as not as described you can still get a refund.

Distant selling regulations apply on YT so goods have to be fit for purpose.

regards
27 March 2023 at 21:04 #639342
Chris Crew
Participant
@chriscrew66644
I have actually got one of these things working in a fashion, it was bunged up with old grease and dirt, but the return spring that rotates the 'scrolls' seems very weak although it may be that a stripping down and really thorough clean and lube may improve things. One of the others seems completely 'dead' and the third is in pieces on my bench. At the moment I have no idea how to re-assemble it but someone has been kind enough to send me a PDF of the manual so I am hoping to know a bit more before I go back into the workshop tomorrow. If I can resurrect at least two of them I will make some new levers with plastic knobs to smarten up their appearance. I will also make MrCrispin's clamping sleeve to fit a device to the Myford tail-stock. All good clean fun!
27 March 2023 at 21:27 #639344
Emgee
Participant
@emgee
I have a couple of heads, 1/4" and 5/16" sizes, both of them are difficult to use as the dies don't stay closed other than holding the lever in position, doesn't seem to latch as it should.

Any tips most welcome.

Emgee
27 March 2023 at 21:40 #639346
peak4
Participant
@peak4
Posted by Chris Crew on 27/03/2023 21:04:16:

I have actually got one of these things working in a fashion, it was bunged up with old grease and dirt, but the return spring that rotates the 'scrolls' seems very weak although it may be that a stripping down and really thorough clean and lube may improve things. One of the others seems completely 'dead' and the third is in pieces on my bench. At the moment I have no idea how to re-assemble it but someone has been kind enough to send me a PDF of the manual so I am hoping to know a bit more before I go back into the workshop tomorrow. If I can resurrect at least two of them I will make some new levers with plastic knobs to smarten up their appearance. I will also make MrCrispin's clamping sleeve to fit a device to the Myford tail-stock. All good clean fun!

Which book have you been sent?
There's a 22MB pdf file available readily on line, or a (slightly) higher quality 75MB version, though I can't remember where I found that one offhand.
Both are 95 page documents entitled The Book Of The Coventry Diehead 25th edition.

The link I posted above on Trurbinejon, has some better quality photo essays

Bill
27 March 2023 at 21:45 #639347
Chris Crew
Participant
@chriscrew66644
Bill, The book I have been sent is the 24th Edition which is a 128 page PDF.
27 March 2023 at 22:25 #639353
JohnF
Participant
@johnf59703
Here are a couple of sites that may be of interest.

http://vintagemachinery.org/pubs/4688/21649.pdf

http://www.namco-tooling.com/coventry-dieheads-chasers.html

John
28 March 2023 at 06:55 #639366
Alan Donovan
Participant
@alandonovan54394
+1 for Oldiron.

If you choose to ask for a refund, ebay have a complaints/dispute procedure you can use. Details of how to proceed are on their website.

Edited By Alan Donovan on 28/03/2023 06:58:57

Edited By Alan Donovan on 28/03/2023 07:04:49

Edited By Alan Donovan on 28/03/2023 07:24:18
28 March 2023 at 10:08 #639374
Bantam Bill
Participant
@bantambill
They are easy to strip down and rebuild, there is a manual available on the interweb. I was given a very rusty seized up 1/2” head, once stripped, cleaned and a few new parts from wiseman it works a treat, you might need to make an adaptor to fit the tailstock.
30 March 2023 at 17:22 #639637
William Howcroft
Participant
@williamhowcroft68688
http://vintagemachinery.org/mfgindex/pubs.aspx
under Alfred Herbert
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