RogerH Posted July 1, 2020 Report Share Posted July 1, 2020 Hi Folks, The other day I picked a TR gearbox for a good price. I have used the top cover for two experiments (which worked OK) So yesterday I decided to take the box apart to see how these things work, They are always shrouded in mystery similar to the diff. There are a number of special 'Churchill' tools recommended but will that stop me I need to remove the main shaft rear race. Today I bought, from Machine Mart, a bearing remover. It certainly looks man enough. One needs to supply two lengths of studding. No problem I have lots of that. The holes in the remover are 10mm. I have 10mm studding with a standard 1.5mm thread But it doesn;t fit in the remover hole !!! The threads in the holes look to have smaller. No problem I'll make a rod with 10mm x 1mm threads. !!! this didn't fit also. Just to make life awkward I have a mice MachineMart metric tap and die kit. The 10mm die has a 1mm pitch , the tap is 10mm x 1.5mm AND the bearing remover is 10mm x 1.25mm aaaarrrgggghhhhh Roger Quote Link to post Share on other sites
RobH Posted July 1, 2020 Report Share Posted July 1, 2020 Ah - standards can be a minefield can't they Roger. As I guess you are aware, but others might not be, Metric Coarse has M10 at 1.5mm pitch but Metric Fine has two choices - 1.25mm and 1mm as you have found. There is even an extra-fine version at 0.75mm. Obviously with the tap and die someone at Machine Mart's supplier has blundered. And people say that Imperial threads are confusing....... https://www.fastenerdata.co.uk/fine-thread Quote Link to post Share on other sites
tim hunt Posted July 1, 2020 Report Share Posted July 1, 2020 Don't talk to me about BSP threads! I have been looking to replace two slotted pop up basin wastes in the en suite. I found a potentially suitable candidate and the spec gave the thread as 1.25"BSP, there was even a 'helpful' diagram with two arrows showing the thread diameter as 1.25 inches with 11tpi (see attached). How was I to know that this meant 1.25"BSP, not an actual thread diameter of 1.25". I measured the thread diameter of an existing fitting as 40.4mm , or about 1.6". I then had a thought and Googled BSP thread diameters - lo and behold 1.25"BSP is actually 40.4mm or 1.6"! Tim Quote Link to post Share on other sites
Ian Vincent Posted July 1, 2020 Report Share Posted July 1, 2020 IIR BSP dimensions are for the internal diameter of the pipe. Rgds Ian Quote Link to post Share on other sites
tr graham Posted July 1, 2020 Report Share Posted July 1, 2020 roger you really need a special grooved clamp that attaches to the bearing for removal richard Rogers of wensum group made a complete tool from scratch if you want his details get back to me and i will send them via another source. regards graham Quote Link to post Share on other sites
RogerH Posted July 1, 2020 Author Report Share Posted July 1, 2020 Hi Folks, As a follow up I contacted MachineMart Technical dept. They were very quick to answer the phone. However they were totally clueless They even suggested it may be 'old money' 3/8 UNF. (or even BSF/W/P/E) - but its not. I have ordered 10mm x 1.25mm tapes and dies from TRacy Tools. What I did find was that they sell the rods (that are usually with a kit) separately but are not in any catalogue. Why didn;t I buy a kit - simple really - there no dimensions so you don;t know what you are buying. Roger Quote Link to post Share on other sites
RogerH Posted July 1, 2020 Author Report Share Posted July 1, 2020 Hi Graham, thanks for that. The MachineMart item will attach positively https://www.machinemart.co.uk/p/cht225-bearing-separator/ Roger Quote Link to post Share on other sites
JohnG Posted July 1, 2020 Report Share Posted July 1, 2020 1 hour ago, tim hunt said: Don't talk to me about BSP threads! I have been looking to replace two slotted pop up basin wastes in the en suite. I found a potentially suitable candidate and the spec gave the thread as 1.25"BSP, there was even a 'helpful' diagram with two arrows showing the thread diameter as 1.25 inches with 11tpi (see attached). How was I to know that this meant 1.25"BSP, not an actual thread diameter of 1.25". I measured the thread diameter of an existing fitting as 40.4mm , or about 1.6". I then had a thought and Googled BSP thread diameters - lo and behold 1.25"BSP is actually 40.4mm or 1.6"! Tim BSP originated, I believe as a thread for gas pipe, hence, it is refered to as 'Gas thread' and shown shorthand as G*/*. As gas pipe is measured by its bore (flow rate capability is all important with gas, so it was the bore that was important, not the OD), the OD was never relevant. Gas pipe can have a good heavy wall thickness, thus a G1 1/4" - 11 thread can be over 1 1/2" OD John Quote Link to post Share on other sites
Rob Salisbury Posted July 1, 2020 Report Share Posted July 1, 2020 H Roger, usually the rear main bearing is just a tight sliding fit on the main shaft, with the mainshaft circlip removed a few well placed whacks with a copper faced mallet on the end of the shaft will get things moving, make sure the layshaft is removed first, the lay cluster dropped to the bottom of the case and the input shaft and bearing pulled out from the front, once the mainshaft has moved forward a bit, the rear bearing can gently be drifted out rearwards (couple of access slots in the case if you look closely) and off the shaft. When you get to the third gear circlip 3 electrical screwdrivers shoved down the slots expand the circlip enough to get it off, forget Churchill, he's old hat!! Cheers Rob PS why not tap threads in your bearing puller to suit the rods you've got? Quote Link to post Share on other sites
RogerH Posted July 1, 2020 Author Report Share Posted July 1, 2020 Hi Rob, thanks for that. I am following the WSM so didn't consider doing any other way. I'll have a look later on. Roger Quote Link to post Share on other sites
AlanG Posted July 1, 2020 Report Share Posted July 1, 2020 These may help. No special tools required. TRTrans02.pdfTRTrans01.pdf Alan. Quote Link to post Share on other sites
cvtrian Posted July 1, 2020 Report Share Posted July 1, 2020 42 minutes ago, RogerH said: Hi Rob, thanks for that. I am following the WSM so didn't consider doing any other way. I'll have a look later on. Roger Roger - You can watch the Pete Cox gearbox seminar on the TR Register website https://www.tr-register.co.uk/past-issue/2015/08/0003/Overdrive-and-Gearbox-Overhauling-with-Pete-Cox-Moss-Europe it might give you a few tips............ Ian Quote Link to post Share on other sites
Lebro Posted July 1, 2020 Report Share Posted July 1, 2020 I've stripped several TRiumph boxes in the past (TR, Stag) Only special tool I have needed was a dummy layshaft to hold the rollers in place. Which is easily made. Bob. Quote Link to post Share on other sites
RogerH Posted July 2, 2020 Author Report Share Posted July 2, 2020 As a finale to this madness In this day and age if you have an item dimensioned in milliMeters one would expect any holes to be threaded in MM. 20 years ago it would be a fair bet that it would be Unified - probably UNC But NO - they use a bloody Victorian thread - BSW. I have no issues over BSW, a mighty fine thread with age and experience but why today when UNC or coarse Metric is around. I didn't even know that the Koreans knew about BSW. So yesterday I spent £25 on metric taps and dies that I do not really need (perhaps one day) and today I bought/buying a 3/8 BSW die. And in reality I don;t even want to take this gearbox apart - I'm just being nosy. Roger Quote Link to post Share on other sites
tr graham Posted July 2, 2020 Report Share Posted July 2, 2020 roger brand new american peterson pacific grinder arrived recently still imperial nuts and bolts , and our bloody engineers trying to beg steal&borrow my best imperial spanners and sockets . graham Quote Link to post Share on other sites
Dic Doretti Posted July 3, 2020 Report Share Posted July 3, 2020 BSF and BSW are British thread forms and worked well and was only changed to the American UNF and UNC after the war when a huge amount of tooling came over from the States to replace that lost in the war. Cheers Richard Quote Link to post Share on other sites
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