Nrhampton Posted August 4, 2022 Share Posted August 4, 2022 Looking for any information on a caterpillar 7J3261WSP, does show signs of military paint, if anyone can help with dating etc. Quote Link to comment Share on other sites More sharing options...
Adrian Barrell Posted August 4, 2022 Share Posted August 4, 2022 It's a 1940 wide gauge D4. Likely originally fitted with a Hyster winch. Quote Link to comment Share on other sites More sharing options...
Nrhampton Posted August 4, 2022 Author Share Posted August 4, 2022 Thank you Adrian for the info, would this also have had a blade fitted as this is missing now? Quote Link to comment Share on other sites More sharing options...
Adrian Barrell Posted August 4, 2022 Share Posted August 4, 2022 Possibly, some wide gauge were fitted with an angledozer but a D4 is not powerful enough to dig with a wide blade so a bulldozer would not work. The SP suffix often indicates a piece of special equipment such as a towing winch. Quote Link to comment Share on other sites More sharing options...
ploughman Posted August 4, 2022 Share Posted August 4, 2022 Would Wide Gauge mean Wide Tracks? If so could be for working in soft ground. Quote Link to comment Share on other sites More sharing options...
Nrhampton Posted August 4, 2022 Author Share Posted August 4, 2022 That’s great thank you for your help Adrian. Quote Link to comment Share on other sites More sharing options...
David Herbert Posted August 4, 2022 Share Posted August 4, 2022 Ploughman, Wide gauge means that the centers of the tracks are further apart than a narrow gauge machine. This does give the opportunity to fit wider tracks as there is a bigger gap between the center line of the track and the sides of the tractor. However wide gauge might be specified to give better sideways stability on slopes or if fitted with any kind of crane that lifts over the side of the machine. Also a wide gauge machine will steer better when pulling hard. David Quote Link to comment Share on other sites More sharing options...
Adrian Barrell Posted August 5, 2022 Share Posted August 5, 2022 On D4, standard gauge is 44" and wide gauge is 60". This is, as David said, the track centres. The serial number starts with the model code, 7J, then the individual serial number and the suffix W indicates wide gauge. Quote Link to comment Share on other sites More sharing options...
David Herbert Posted August 5, 2022 Share Posted August 5, 2022 (edited) Just to put this info in one place, it was also possible to order a D4 (and many other crawler tractors) with long track frames. The sprocket was in the same place but the track frames had an additional bottom roller so the idler moved forwards by about a foot. This gave more length of track on the ground for lower ground pressure. Long track frames were also used to give much more stability for crane or loading shovel conversions where it was normal for the track frames to be rigidly bolted to the frame of the machine rather than being able to pivot at the back and the weight of the machine carried on a massive transverse leaf spring whose ends pressed down on the track frames. The center of the spring was pivoted to the underside of the machine so that the front of the tracks had springing and if one went up the other went down. This allowed the tracks to follow the contour of the ground but was not as stable as a rigid track machine. David Edited August 5, 2022 by David Herbert 1 Quote Link to comment Share on other sites More sharing options...
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