will_warne Posted August 14, 2007 Share Posted August 14, 2007 After a little while on the lathe I've managed to drill the end of the mainshaft for my 8074. I'd been hoping to cut a thread in it to take a bolt to hold a cap which, in turn, would hold the brake end plate on (a la gigglepin mainshaft). However, that's not going to happen as the shaft is hugely hard (HHS won't touch it, neither will cobalt steel) unless its possible to get a very hard tap (I've never come across one, neither had the cap at my local tool shop). The two solutions I'd come up with is to insert a stud into the newly created hole and then weld it to the end of the mainshaft (so the cap would be held in place with a nut) or else plug weld the hole and redrill it and then tap it. The latter seems a more elegant solution although I'd be worried about the heat build up damaging the heat treatment. Any thoughts on this? Also, does anyone see any other options? Cheers, Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted August 15, 2007 Share Posted August 15, 2007 Will, have you considered annealing it, tapping it, then re-hardening it? All seems like a lot of ballache if you can just weld a threaded stud on the end? Probably take less time than typing the question - especially if you have a lathe to centre it all nicely? You could always harden it again afterwards? Just make sure the weld is good and strong. Al. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted August 15, 2007 Share Posted August 15, 2007 Just make sure the weld is good and strong. Yeah, what Al said - get someone else to do it Quote Link to comment Share on other sites More sharing options...
SiWhite Posted August 15, 2007 Share Posted August 15, 2007 I know somwone that can help.... PS Are you going to come back and clear up the rest of this swarf or did you want me to do it Quote Link to comment Share on other sites More sharing options...
Mark Posted August 15, 2007 Share Posted August 15, 2007 Will, I gave up with trying to drill and tap the shaft on mine, and went down the route of drilling and tapping the outer plate of the brake disc and using 3 button headed stainless M5 screws to hold the circlip on. It isn't the most elegant solution, and there isn't a huge amount for room to do it, but it has worked very well... I havn't done any pictures as it is so similar to the 8274 fix it didn't seem worth it. I believe Lewis had some success tapping the shaft with some uber-expensive unobtaium tap.... Cheers Mark Quote Link to comment Share on other sites More sharing options...
Tonk Posted August 15, 2007 Share Posted August 15, 2007 cobalt will drill the hole but theres no way to tap it, i've done the 3 bolt method which takes about 15 minutes to do if u weld something thats hardened then preheat it or the welds can crack, tig it rather than mig it too Quote Link to comment Share on other sites More sharing options...
will_warne Posted August 15, 2007 Author Share Posted August 15, 2007 I know somwone that can help.... PS Are you going to come back and clear up the rest of this swarf or did you want me to do it Hmm, I did make rather a lot of swarf Al, I don't think re-heat treating is an option - I've no idea what the alloy is or how it was done originally. Plus the shaft has added complictions like having a gear machined into it. Tonks, cobolt wouldn't touch the shaft I've got. It might work on some but my shaft was having none of it. Also, if I plug weld after reheating will there be an issue if I let the shaft cool in air (ie annealing)? Might it be worth quenching it in oil? Also, when I come to preheat what sort of temperature/colour should I be aiming for? Mark, I thought about the 3 bolt technique but that would've been too easy Quote Link to comment Share on other sites More sharing options...
simonr Posted August 15, 2007 Share Posted August 15, 2007 It might not be strong enough, but could you put a riv-nut in the hole? That would expand to fill the hole and hopefully grip the sides sufficiently. Then make a cap for the end which in turn holds the circlip in place, particularly if the cap stops the circlip expanding out of it's groove - then the force on the riv-nut would be trivial. There's an idea! - a cap as above, just held in place with a magnet! Si Quote Link to comment Share on other sites More sharing options...
northernchris Posted August 15, 2007 Share Posted August 15, 2007 Or just use a small raw bolt or even spend some of your wealth with gigglepin??? Quote Link to comment Share on other sites More sharing options...
will_warne Posted August 15, 2007 Author Share Posted August 15, 2007 It might not be strong enough, but could you put a riv-nut in the hole? That would expand to fill the hole and hopefully grip the sides sufficiently. Then make a cap for the end which in turn holds the circlip in place, particularly if the cap stops the circlip expanding out of it's groove - then the force on the riv-nut would be trivial.There's an idea! - a cap as above, just held in place with a magnet! Si The rivnut's an idea Si. I'd also though about chemical metal and cutting a thread in that. I don't think the strength would be an issue as there's 20mm of thread however I was worried about the plug slipping inside the hole. Quote Link to comment Share on other sites More sharing options...
northernchris Posted August 15, 2007 Share Posted August 15, 2007 Will can't you just press a stud in then cross drill and pin it?? It would,nt be a hard job. Quote Link to comment Share on other sites More sharing options...
Tonk Posted August 16, 2007 Share Posted August 16, 2007 even spend some of your wealth with gigglepin??? thats wot i'm doing for my front winch Quote Link to comment Share on other sites More sharing options...
Tonk Posted August 16, 2007 Share Posted August 16, 2007 Will, i thought u had an uprated mainshaft? Quote Link to comment Share on other sites More sharing options...
Lewis Posted August 16, 2007 Share Posted August 16, 2007 or even spend some of your wealth with gigglepin??? Gigglepin dont make uprated shafts for 8074's Quote Link to comment Share on other sites More sharing options...
will_warne Posted August 16, 2007 Author Share Posted August 16, 2007 Gigglepin dont make uprated shafts for 8074's Exactly. The 8074 is a nicer design to the 8274 aswell as there's no undercut in the shaft. Chris, cross pinning isn't a bad idea. Right, I've got a few ideas to be getting along with - I just need to decide which to do now... Quote Link to comment Share on other sites More sharing options...
Tonk Posted August 16, 2007 Share Posted August 16, 2007 Right, I've got a few ideas to be getting along with - I just need to decide which to do now... or what u r capable of doing Quote Link to comment Share on other sites More sharing options...
Jon White Posted August 16, 2007 Share Posted August 16, 2007 Dont know why he doesnt just weld the brake to the mainshaft........ After all it'd be easy to remove for servicing........ Quote Link to comment Share on other sites More sharing options...
Lewis Posted August 16, 2007 Share Posted August 16, 2007 Replace the ciclip with a peg that runs through the shaft? Its a bit of a bodge IMO, but I tried it on my old 8274 and it worked well, at least once I had replaced the splitpin with a tool steel peg Quote Link to comment Share on other sites More sharing options...
Mark Posted August 16, 2007 Share Posted August 16, 2007 Personally, I like Chris's suggestion of turning up a press fit, or maybe a even shrink fit pin which is crossdrilled. Nice and simple Quote Link to comment Share on other sites More sharing options...
will_warne Posted August 16, 2007 Author Share Posted August 16, 2007 Personally, I like Chris's suggestion of turning up a press fit, or maybe a even shrink fit pin which is crossdrilled. Nice and simple Yes, I think this may be the sort of way I go. Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted August 16, 2007 Share Posted August 16, 2007 Why not put it back in the lathe and screwcut a thread inside it? Failing that pressing a stud in it i'll do the job just fine. Quote Link to comment Share on other sites More sharing options...
will_warne Posted August 16, 2007 Author Share Posted August 16, 2007 Why not put it back in the lathe and screwcut a thread inside it?Failing that pressing a stud in it i'll do the job just fine. Dan, I though about cutting a thread but what do you use to cut an M8 x 1.25 female thread? The stud is the option I like most at the moment. Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted August 16, 2007 Share Posted August 16, 2007 Dan, I though about cutting a thread but what do you use to cut an M8 x 1.25 female thread?The stud is the option I like most at the moment. Grind yourself up a tool then set the screw cutting gearbox for the correct pitch for the thread you want to create then set the tooling up. You may have to do a few passes to get the correct thread depth, especially in hard material, it's also important to keep an eye on tool deflection as you get deeper into the hole as it is very easy to turn a tapered thread as the tool is pushed away by the material. Also if you have a totally free choice on thread why go for such a course and relatively poor thread form as m8 x 1.25? 5/16 unf would be much more suited to this (and just about every other) application. Quote Link to comment Share on other sites More sharing options...
simonr Posted August 16, 2007 Share Posted August 16, 2007 Do any of you have an 8274 (or 8074) where the circlip is prone to popping out? Can you reliably repeat the failure? If so, would you like to try out an idea fo me? I'll make it, you try it and keep it if it works? PM me if you want to join in? Si Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted August 17, 2007 Share Posted August 17, 2007 Do any of you have an 8274 (or 8074) where the circlip is prone to popping out? Can you reliably repeat the failure?If so, would you like to try out an idea fo me? I'll make it, you try it and keep it if it works? PM me if you want to join in? Si Lewis has one that is in the process of spitting its circlip out. I too had an idea regarding an alternative method of holding the brake on. It involved boring a hole in the center of a 50x50x20mm block of steel with a "lip" at one end to sit in the circlip grove, then band saw it in half leaving you with two pieces 50x25x20 each with a semi circular rebate with a lip at one end one half would then be drilled clearance then the other would be tapped. The two halfs could then be bolted together over the end of the brake shaft preventing the escape of the brake assy. Quote Link to comment Share on other sites More sharing options...
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