Old Bill Posted June 16, 2009 Share Posted June 16, 2009 We are actually very fortunate in that the rest of the diff was in the casing so we hope to recover it all. Our problem is that we have no diff for the next project, a Thornycroft 'J- Type' which is not in nearly such good condition as the Dennis. If any of our friends out there, particularly in Oz or New Zealand, should come across a Thornycroft J-Type back axle with differential, we would be extremely pleased to hear about it! This forum reaches the parts other forums cannot reach! (At least I hope so!). Cheers! Steve Quote Link to comment Share on other sites More sharing options...
abn deuce Posted June 16, 2009 Share Posted June 16, 2009 Do I detect some spanner envy? I think with spanners that size steel toe boots are a requirement ! Quote Link to comment Share on other sites More sharing options...
Great War truck Posted June 22, 2009 Author Share Posted June 22, 2009 Well the worm has had a good look at, and there appears to be no problem with it. it just needs a good clean up: Tim (too) Quote Link to comment Share on other sites More sharing options...
Great War truck Posted June 22, 2009 Author Share Posted June 22, 2009 Tony has had a go at cleaning the Bearings in the Worm assembly. The constituents of the Thrust Bearing were very oily and have cleaned up well so that we think that we can use this one again. The two Worm Journal Bearings were thick with sand and even after cleaning they are still solid. They will have to be replaced. The numbers on them tie up with the numbers in the Parts Manual. Who wants to guess how much replacements will cost? Quote Link to comment Share on other sites More sharing options...
Chrisg Posted June 22, 2009 Share Posted June 22, 2009 Are both the ball bearings the same? I'll check prices for you tomorrow Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted June 22, 2009 Share Posted June 22, 2009 Yes - both the same. O/D 5" I/D 2.25" Width 1.25" Tony Quote Link to comment Share on other sites More sharing options...
Stormin Posted June 22, 2009 Share Posted June 22, 2009 This might give a guide price. http://www.bearingboys.co.uk/MJ2.1_4_Imperial_Ball_Bearing-5644-p Listed as the budget option :shake: Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted June 22, 2009 Share Posted June 22, 2009 Thanks Norman and Chris, too. I knew that these didn't come cheap! It is possible that Steve may also be able to get them through his work contacts - so it will be case of "exploring the market" for the best price! One of us will let you know what happens! Tony Quote Link to comment Share on other sites More sharing options...
Chrisg Posted June 22, 2009 Share Posted June 22, 2009 I run a bearing business I'll see what can be done Quote Link to comment Share on other sites More sharing options...
Great War truck Posted June 22, 2009 Author Share Posted June 22, 2009 Crikey, i didnt realise it was bearings that you were in to. Thats very good of you. Thanks. Tim (too) Quote Link to comment Share on other sites More sharing options...
Stormin Posted June 23, 2009 Share Posted June 23, 2009 I run a bearing business I'll see what can be done That may explain why you are undisputed skittles champ, just getting a big ball to run true! Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted June 23, 2009 Share Posted June 23, 2009 Tim, from an engineering point of view does it not seem strange that they used ball bearings to take the radial loads rather than roller bearings, leaving the end thrust to the dedicated thrust bearings? Quote Link to comment Share on other sites More sharing options...
Stormin Posted June 23, 2009 Share Posted June 23, 2009 Tim, from an engineering point of view does it not seem strange that they used ball bearings to take the radial loads rather than roller bearings, leaving the end thrust to the dedicated thrust bearings? A good point Mike, Were taper roller bearings available at this time? Was it done just because it was easier to change the thrust bearings than main bearings? Be interesting to get Tim's and other views. Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted June 23, 2009 Share Posted June 23, 2009 Well, I can't answer that one - and I guess that Tim will not be able to either - but we both know a man whom we expect can - Steve ! He will pick this up when he is home from work later. Warch this space! Tony Quote Link to comment Share on other sites More sharing options...
Chrisg Posted June 23, 2009 Share Posted June 23, 2009 Yes - both the same. O/D 5" I/D 2.25" Width 1.25" Tony PM sent Quote Link to comment Share on other sites More sharing options...
Old Bill Posted June 23, 2009 Share Posted June 23, 2009 Ball versus roller bearings. Well, I don't know! I have had a chat with my colleagues about this one and we have not reached a firm conclusion although this is the way our thoughts are going at the moment. With a worm drive axle, the axial loads on the worm are very significant and in both directions as the transmission braking force is through the worm as well. We therefore think that the loads are probably a bit big for taper rollers hence the thrust race and separate radial bearings. Now the radial loads are probably relatively modest, in comparison, but the speed is fairly high, approaching 2000rpm, for which ball races are better suited so that might be the reason they were selected. The other point made was that it might be easier to automatically mass-produce ball bearings rather than rollers so they were just easier to get at the time. I have the draughtsman's name but he will be long dead so I guess we will never know for certain. I should be pleased to hear any other theories! Steve Quote Link to comment Share on other sites More sharing options...
Chrisg Posted June 23, 2009 Share Posted June 23, 2009 Taper rollers were in production at the very end of the 19th century so they may have been more expensive and also a new idea. So they may have chosen something more proven. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted June 23, 2009 Author Share Posted June 23, 2009 Tony has been very busy today working on the worm. Sorry if you are on dial up as all these pictures will take an age to load, but i hope you find them interesting. These three pictures show the Worm Shaft Thrust Bearing Adjusting Ring - before and after the paraffin Bath. This Group show the Worm Shaft Coupling Sleeve - again before and after the Paraffin Bath. One end of this has been open to the elements over the years and consequently the splines at that end are badly rotted. This will have to be replaced with a new one - but it might be just too much of a challenge for the home workshop! We shall see! Quote Link to comment Share on other sites More sharing options...
Great War truck Posted June 23, 2009 Author Share Posted June 23, 2009 This is the Worm Shaft Thrust Bearing Housing - cleaned up very nicely and no problem. This is the Worm Shaft Journal Bearing Lock Nut at the front end. Cleaned up nicely. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted June 23, 2009 Author Share Posted June 23, 2009 The first picture shows the Worm straight out of the Bath - all sand and grease removed. The remainder of the pictures show close-ups of parts of the worm after some light cleaning. These show the pitting in the worm which causes concern. Hopefully we will get away without having to make a new one. There also seems to be some "grooving" at the bottoms of the thread channels in some places. Although we have not yet touched the worm-wheel, we know that to be quite worn. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted June 24, 2009 Share Posted June 24, 2009 Steve, Tim, Tony, Great job. Is that an oil scoop on the splined worm shaft coupler? It seems very Dennis. The bearing set-up was proven on the early axles (from 1904) at which point Timkin had only been in business selling his bearings for five years, so they may have been a little new at time. Keep up the good work, Ben Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted June 24, 2009 Share Posted June 24, 2009 An Oil-scoop it is, Ben! Tony Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted June 25, 2009 Share Posted June 25, 2009 As someone who is attempting to restore their first veteran truck (a 1908 civilian Dennis 3 ton) I have great respect for this team. You have to start with an incredible amount of research to work out what the missing parts should be and have immense patience to wait for them to turn up. Very few parts can be bought off the shelf and you end up making virtually every nut and bolt if you want things to be to the original pattern. You need sound engineering skills or very deep pockets (and probably both ideally) along with thousands of hours. The part I have found most difficult is deciding what to rescue, and what to leave where it is (even if that does risk it getting scrapped). The engineering challenge is however what makes it all worth while in my opinion. If you like to reverse engineer parts, learn disappearing crafts and don’t like sitting in front of the TV of an evening then this is the hobby for you. Ben Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted June 25, 2009 Share Posted June 25, 2009 With so much time having passed, then the later you start off trying to put one of these trucks together then the more difficult it will prove to be - there are only so many parts left now after the passage of so many years, and it will become even more difficult to find them as time goes on again. I know that you are finding this and I can only commend you for your persistance and dedication in the hunt! We will help in any way that we can - and you know that we have a spare Subsidy Lorry Chassis here if you do eventually decide to go down that road! It is yours just for the asking! Congratulations in what you have achieved and I am sure that Readers here will be interested to know what you have acquired and how it came to be! Tony Quote Link to comment Share on other sites More sharing options...
Marmite!! Posted June 25, 2009 Share Posted June 25, 2009 Congratulations in what you have achieved and I am sure that Readers here will be interested to know what you have acquired and how it came to be! Hi Ben, Please tell us all about your new project in a new thread.. Cheers Lee Quote Link to comment Share on other sites More sharing options...
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