SimonBrown Posted March 24, 2020 Author Share Posted March 24, 2020 6 hours ago, Henry Harris said: Tracy Tools in Torquay can supply "Admiralty" taps and dies up to 2" dia. HSS or carbon steel. https://www.tracytools.com/taps-and-dies/whitform-taps-dies?page=5 I have no idea how I missed that... Thank you very much for sharing the link. Tomorrow - if they are open - I will order one. Quote Link to comment Share on other sites More sharing options...
Henry Harris Posted March 24, 2020 Share Posted March 24, 2020 Admiralty threads are used in a few places on 1922/39 Austin 7hp cars. I suspect they were common on most Longbridge products into the '60's. Tracy tools are well regarded by the Austin 7 community. 1 Quote Link to comment Share on other sites More sharing options...
Ex-boy Posted March 24, 2020 Share Posted March 24, 2020 Good to have this back underway Simon. Long may the lockdown last from my selfish point of view. 1 Quote Link to comment Share on other sites More sharing options...
attleej Posted March 25, 2020 Share Posted March 25, 2020 Simon, Good news about the die. Is the bore machined? If it is, it might be possible to make a special die holder that picks up on the machined bore. In my experience, it is very difficult to start a die in such circumstances without it going off course and cutting a new thread.. John Quote Link to comment Share on other sites More sharing options...
BC312 Posted March 25, 2020 Share Posted March 25, 2020 I may have a die as i had quite a few taps and dies given to me when they cleared out a camp years ago. Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted March 25, 2020 Author Share Posted March 25, 2020 (edited) 3 hours ago, attleej said: Good news about the die. Is the bore machined? If it is, it might be possible to make a special die holder that picks up on the machined bore. In my experience, it is very difficult to start a die in such circumstances without it going off course and cutting a new thread.. I will have to check - as of now I am probably one of the few who a) work at home a lot so nothing much changes and b) engaged in something that is seen as important enough to keep going, for now at least and c) I'm looking ahead & planning for a time when I too have more time on my hands. But its a good point. Some of the threads need more TLC than others. The other factor is how these were originally made - the threads were cut prior to assembly/welding onto the barrel...so there is limited room and there is no way a standard die wrench will work...like everything else, the torpedo engine is unique in that respect and never intended for overhaul. Edited March 25, 2020 by SimonBrown Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted March 25, 2020 Author Share Posted March 25, 2020 (edited) 3 hours ago, attleej said: Good news about the die. Is the bore machined? If it is, it might be possible to make a special die holder that picks up on the machined bore. In my experience, it is very difficult to start a die in such circumstances without it going off course and cutting a new thread.. Duplicate post... Edited March 25, 2020 by SimonBrown Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted March 25, 2020 Author Share Posted March 25, 2020 1 hour ago, BC312 said: I may have a die as i had quite a few taps and dies given to me when they cleared out a camp years ago. That would be great - its 1 5/8" Whitworth fine 20tpi. Quote Link to comment Share on other sites More sharing options...
MatchFuzee Posted March 25, 2020 Share Posted March 25, 2020 46 minutes ago, SimonBrown said: ...so there is limited room and there is no way a standard die wrench will work... Is a thread file an option? https://www.cromwell.co.uk/shop/thread-restoring-files/thread-restoring-files/thread-restoring-files/f/61 Quote Link to comment Share on other sites More sharing options...
BC312 Posted March 25, 2020 Share Posted March 25, 2020 Hi Simon I had a look, the largest I have is about 1' 1/4 whitworth. Sorry about that. As for using a die I would use a die nut as you don't need a die wrench that would get in the way of the rest of the engine. I have in the past used grinding paste to work a thread on freely. One thing you won't be able to do is restore the missing thread's when retapping. The worst you can do is cross thread especially this size. . 1 Quote Link to comment Share on other sites More sharing options...
attleej Posted March 25, 2020 Share Posted March 25, 2020 I agree that The worst you can do is cross thread especially this size. That is why I think that what is needed is a special die holder that is machined to 'pick up' on what I hope is the machined bore. Thus the die would be held perfectly square and would be much less ;likely to go cross threaded. There would also be no question of handles. It would have a square or hex drive. John Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted March 26, 2020 Author Share Posted March 26, 2020 14 hours ago, BC312 said: Hi Simon I had a look, the largest I have is about 1' 1/4 whitworth. Sorry about that. No problem - thanks for looking. I agree; a die nut would be best, for many reasons. Quote I agree that The worst you can do is cross thread especially this size. That is why I think that what is needed is a special die holder that is machined to 'pick up' on what I hope is the machined bore. This is just one reason - the opportunity for cockup being extremely high - I have put the project down. Time to think about how to solve it rather than rush... I think the idea of a spigot to follow the bore might be sound...I need to have a look at them. Square or hex drive would be required too. I will post up some more photos. Quote Link to comment Share on other sites More sharing options...
BC312 Posted March 26, 2020 Share Posted March 26, 2020 It might be worth getting a engineer machinist to have a look and give an opinion. I have a mate who may be able to help out. I will send him the picture and see the best way. 1 Quote Link to comment Share on other sites More sharing options...
attleej Posted March 26, 2020 Share Posted March 26, 2020 I thought that I was quite handy! John Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted March 26, 2020 Author Share Posted March 26, 2020 1 hour ago, attleej said: I thought that I was quite handy! Oh yes, very much so - much appreciated. Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted June 21, 2020 Author Share Posted June 21, 2020 Finally I got a little spare time to start thinking and tinkering with the torpedo engine. The barrels will be going for some light soda blasting at some point, mainly to remove a little surface corrosion. One nagging thought; the bolts that hold the barrels onto the crank case are (like most things) somewhat unusual. Normally I would expect to see studs, but not here. What we have are pan head bolts with a tiny pip on the underside of the pan head. As far as I can tell the pip is intended to stop the screw rotating on assembly...the slot is a nightmare to get to when reassembling and to be quite frank the pip is too small to be really effective. It all serves as a reminder this engine is most likely a prototype and a proof of concept. No one in their right mind would want to put this thing into series production. Anyway, I am contemplating using a modern Loctite to secure the pan heads in place. This goes against the grain a little, but it will make it easier to reassemble. There does appear to be some black adhesive of some form in the holes, but quite what it might be is beyond me. So...What are the collective thoughts of the forum on this idea? I am open to struggling, or taking a short cut. Should I be that precious or make life easy? Is modern Loctite an act of heresy? Or just common sense? 2 Quote Link to comment Share on other sites More sharing options...
MatchFuzee Posted June 21, 2020 Share Posted June 21, 2020 (edited) There were metal to metal bonding adhesives in WW2 but not Loctite. Please see page 6:- https://books.google.com/books/about/Handbook_of_Adhesive_Technology_Revised.html?id=XYbHqiapRjsC Edited June 21, 2020 by MatchFuzee Quote Link to comment Share on other sites More sharing options...
attleej Posted June 21, 2020 Share Posted June 21, 2020 Simon, I would not hesitate to use loctite. For instance, why risk having a stud unscrew rather than the nut with all the attendant difficulties when a dab of loctite will solve the problem. Easy to get undone with heat if nec. It is difficult enough to work on old equipment without turning down some modern technology. John Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted June 23, 2020 Share Posted June 23, 2020 Are they blind holes or through holes, if the latter the black gunge is probably a sealant to prevent oil leaks via the threads? Quote Link to comment Share on other sites More sharing options...
ploughman Posted June 23, 2020 Share Posted June 23, 2020 On 6/21/2020 at 3:03 PM, SimonBrown said: Finally I got a little spare time to start thinking and tinkering with the torpedo engine. The barrels will be going for some light soda blasting at some point, mainly to remove a little surface corrosion. One nagging thought; the bolts that hold the barrels onto the crank case are (like most things) somewhat unusual. Normally I would expect to see studs, but not here. What we have are pan head bolts with a tiny pip on the underside of the pan head. As far as I can tell the pip is intended to stop the screw rotating on assembly...the slot is a nightmare to get to when reassembling and to be quite frank the pip is too small to be really effective. It all serves as a reminder this engine is most likely a prototype and a proof of concept. No one in their right mind would want to put this thing into series production. Anyway, I am contemplating using a modern Loctite to secure the pan heads in place. This goes against the grain a little, but it will make it easier to reassemble. There does appear to be some black adhesive of some form in the holes, but quite what it might be is beyond me. So...What are the collective thoughts of the forum on this idea? I am open to struggling, or taking a short cut. Should I be that precious or make life easy? Is modern Loctite an act of heresy? Or just common sense? We had a similar situation but much larger. The Pivot pins on our Railway ballast hopper has 65mm dia pins as a pivot point on the hopper doors. We found out the hard way thaat small 5mm stubs located in the pin housing and to undo or make up you needed to hold the shaft from turning and keep the stud end located firmly in the socket otherise the stud would shear off. Quote Link to comment Share on other sites More sharing options...
andym Posted July 23, 2020 Share Posted July 23, 2020 I just came across this and wondered if it may open any further avenues of exploration? https://www.deeperdorset.co.uk/torpedoes-running/ Andy Quote Link to comment Share on other sites More sharing options...
terryb Posted December 1, 2023 Share Posted December 1, 2023 update on the torpedo engine-now restored and on display at the RAF Manston History Museum. Many thanks to Simon for his kind donation 7 Quote Link to comment Share on other sites More sharing options...
SimonBrown Posted December 1, 2023 Author Share Posted December 1, 2023 That is looking really good Terry. Many thanks for letting us know. 1 Quote Link to comment Share on other sites More sharing options...
Adrian Dwyer Posted December 1, 2023 Share Posted December 1, 2023 23 minutes ago, SimonBrown said: That is looking really good Terry. Many thanks for letting us know. Fabulous piece of engineering, great project and an enthralling thread! As others have noted, thank you for sharing! A Quote Link to comment Share on other sites More sharing options...
andym Posted December 3, 2023 Share Posted December 3, 2023 Wonderful! Andy Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.