miketomcat Posted December 31, 2014 Share Posted December 31, 2014 I'm in the process of figuring out how I want to do the vector winch system on the ibex. As some already know the winch is mounted facing backwards the rope runs to the rear cross member round a pulley across to the chassis rail round another pulley then down a tube to the front. Normally the rear pulley is a snatch block on a removable pin but I'm not keen on this so I want a fixed pulley in the rear cross member. I've got some nice pulleys with a bearing in and a centre hole of 15mm so that rules out a bolt so it's going to have to be a pin but what grade if I had used a bolt it would of been 10.9 as this could have all the winch can muster on it. On a side note my plan is then to have an aluminium fairlead just behind the rear pulley with a hole that's just wider than the pulley so for a rear pull you just pull the rope out through the fairlead and use a snatch block. This means one side is stationary between pulley and fairlead then on to the front the other side will roll on the pulley or slide on the fairlead (depending on angle) then back to the winch. Can anyone foresee a problem that I've missed the rope will be dyneema not wire. Mike Quote Link to comment Share on other sites More sharing options...
Team Idris Posted December 31, 2014 Share Posted December 31, 2014 The only tech thing I can see is that the chassis pulley has the front pull on it and the side pull, so vector wise a 5 tonne rope force creates maybe a 7+ tonne directed at a 45 degree angle. But I think a low grade steel would do at 15mm. Depends where it shoots off to if it breaks We run big ally bobbins on ball race bearings so the rope has a chance of staying on them for 90% of pulls. Getting the rope down the side of a pulley is bad as it always snaps at that stressed point in the fibres. I have various bits of tube to guide it in. Behind the vertical bobbins are two horizontal rollers. They are wider than the gap between the bobbins. I think you mean a pulley in the rear cross member with a 'U' shaped ally fairlead? Where the slot goes left-right and the open end of the 'U' points to the chassis pulley? So the rope doesn't touch the ally work on front pulls, but directs the rope on other pulls. Sounds really good It is real easy to cock it up. My side/corner fairleads make the rope go past the exhaust pipe in use Thinking of every eventuality sure is difficult. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted December 31, 2014 Share Posted December 31, 2014 For pins like that then save any hastle by using either 16T 19T or 24T or if you want stainless then 431S29T is what you want. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted December 31, 2014 Author Share Posted December 31, 2014 Kind of like this only the letter box will be only a little wider than the pulley. I'll probably have a flat plate top and bottom of the pulley. Mike Quote Link to comment Share on other sites More sharing options...
B reg 90 Posted December 31, 2014 Share Posted December 31, 2014 Well ideally you need to calculate the load and work out what thickness pin you need. However I would buy a bigger 10.9 bolt and machine the pin out of it. Make sure you get a bolt just big enough as the heat treatment is most effective near the surface. If you want to make from round bar I would suggest a 1.25% chrome steel like bs970 709m40 in the T condition. Stud bolts are made from this for the oil industry. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted December 31, 2014 Share Posted December 31, 2014 Looks like it will be tidy and run well, by the photo. I was thinking it would rope-saw a slot in the ally fair lead with the front rope always being on the same bit. (Hence the 'U' shape I had in mind) But I guess it's done 80 of the 90 degrees turn by then. Maybe there is a bearing with the same outer diameter but a bigger inner? If you do need to machine something I wonder if it is better to machine the pulley for a bearing you can find stock bar for. Isn't 15mm just about no where for anything? The Bearings should last for ever but mine pack clay in there. I need to look before I next race thinking about it I worry about the slack rope jamming on the inside on mine. Has the rope somewhere to lie behind the pulley on yours? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted December 31, 2014 Share Posted December 31, 2014 Well ideally you need to calculate the load and work out what thickness pin you need. However I would buy a bigger 10.9 bolt and machine the pin out of it. Make sure you get a bolt just big enough as the heat treatment is most effective near the surface. If you want to make from round bar I would suggest a 1.25% chrome steel like bs970 709m40 in the T condition. Stud bolts are made from this for the oil industry. EN19T as per my post.... Theres a good source of that in your bog standard axle, Land Rover made the half shafts from it. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted December 31, 2014 Author Share Posted December 31, 2014 I've no idea how to calculate the winch is an ep9 (9000lbs) the truck will be in the region of 2000kg unladen. Below is a very bad picture the rope (in red) comes from the winch round the pulley across at 45° to a second pulley (nearly circular white bit) then down the chassis rail inside a tube straight line parallel to the centre line to the front. This picture is the standard set up to give you the idea. In the second picture you can see the pin where my pulley will be here the snatch block is held in place by it. Mike Quote Link to comment Share on other sites More sharing options...
miketomcat Posted December 31, 2014 Author Share Posted December 31, 2014 How easy is EN19T to machine my father used to be a machinist and has a lathe so I could give him an old halfshaft or would I be better buying a bit as close as possible to size. Mike Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted December 31, 2014 Share Posted December 31, 2014 How easy is EN19T to machine my father used to be a machinist and has a lathe so I could give him an old halfshaft or would I be better buying a bit as close as possible to size. Mike Depends on the machine and tools available..... I quite enjoy it, but same kit and EJParrott hates it (we are the day and night shift on one of the vertical borers at work) if in doubt, let us know, we'd be happy to help. Quote Link to comment Share on other sites More sharing options...
Cheesy Posted December 31, 2014 Share Posted December 31, 2014 That seems a bit of an odd ball bearing to have a 16mm bore, is it imperial? I was going to suggest looking in a bearing catalouge to see if there is a bearing that will fit in the pulley with an inner race size that is more suitable for an off the shelf bolt..... Could you just use a 5/8 UNF cap screw? Quote Link to comment Share on other sites More sharing options...
miketomcat Posted January 1, 2015 Author Share Posted January 1, 2015 Thank you for the replys I think I've bottomed out what I'm going to do/use dad is happy to machine if need be. The bearing is definitely 15mm but I'm happy we can work with that. Mike Quote Link to comment Share on other sites More sharing options...
Cheesy Posted January 2, 2015 Share Posted January 2, 2015 Woops my reading comprehension is a bit off at the moment! Quote Link to comment Share on other sites More sharing options...
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