I have collected several sets of Marzocchis throughout the years that i've picked up cheap because they've been listed as 'spares and repairs' - mostly '04s.
A couple need 20mm thru axles and one is QR 20. I was naive in thinking i would come across these axles cheap at some point but I haven't and i don't want to spend £40 a pop from CRC.
I have thought about using 20mm steel tube, cut slightly shy of the full length between the leg feet and using a QR skewer with washers either side to secure it into place. Can anyone with more knowledge and understanding of these systems tell me why this might be a sh1tty idea?
P.s i'm no downhiller, aggressive singletrack rider.
Cheers all!
I tried this and while I was able to buy a piece of aluminium tube that was nominally 20mm diameter it was not a good fit in the drop out, so I've never used it.
Too small or too big? I would think about alu but not confident in the shear strength. Steel will let me know before it decides to quit
too small.
Aluminum alloy is plenty strong enough
Not sure if yours is the same but the axle for my Marzocchis is 22mm on the right hand side dropping to 20mm where it goes through the hub then threaded on the end. Your straight through axle would need to be thinner at the threaded part to clear the threads.
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I see they do others which are straight with end caps so if you have that style then no reason why it shouldn't work
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If you are trying to mimic that then thick wall aluminium tube should be fine. I think I'd want to make top hat washers to keep everything central. Beefier option would be a solid bit of aluminium then tap the ends and put a couple of bolts in. Tricky bit will be finding the right size tube/bar. Sizing is a bit approximate. Easy if you have a lathe, though
Mine is straight with end caps like that last one. Although I wouldn't realy bother with the end caps - the pinch bolts will be fine.
I once did a lap of Cwmcarn without the pinch bolts done up.
Would you get away without the end caps, though? On mine in needs to be tightened to pinch the hub or there is noticeable play.
I'd expect the pinch bolts to hold it in, but that's a pure guess 🙂
Yeah, I'm pretty sure it wouldn't fall out. Just that on mine it needs the fork legs to be squeezed together slightly or there is play in the hub. Maybe my hub is a little worn though
I've a set of pretty unused 55s in my loft - they were used for a year and leak from the bottom after I shim stacked them. The axle is good (pretty sure its like new) - make me an offer if you want them..
What age are the 55s? How much travel?
A foot of 20mm dia aluminium bar can be had for under a fiver on eBay, some "precision hacksawwing", a couple of M16 dome head bolts a 13.8mm drill and a tap you could bodge a passable axle...
Unless you can lay your hands on a lathe to do a neater job.
Thanks for all the posts lads.
What I need is what [b]nickjb[/b] has posted. 148mm axle, 20mm. I have one for a pair of DJ1s and have confirmed that they fit all the forks I am after making axles for.
Thanks, I will look for this.Aluminum alloy is plenty strong enough
A foot of 20mm dia aluminium bar can be had for under a fiver on eBay, some "precision hacksawwing", a couple of M16 dome head bolts a 13.8mm drill and a tap you could bodge a passable axle...Unless you can lay your hands on a lathe to do a neater job.
Funnily enough, I do actually have access to a lathe, but not sure whether there are cutting bits available. I also don't have a tap and die set but I would be willing to invest.
Good news but this is what I am wondering...I once did a lap of Cwmcarn without the pinch bolts done up.
I think before I start on the lathe route I will buy some A2 M5, 25mm washers as these will fit perfectly into the exterior of the dopouts. The proper axle is 24mm but I've tightened up the dropouts and measured with verniers and it comes out at 25mm, plus M5 inner diameters will perfectly accommodate and centre QR skewers.On mine in needs to be tightened to pinch the hub or there is noticeable play.
I will get all the bits tonight and start my first one next week. I was also thinking about buying a 9mm axle and using M10 washers but they're still expensive to buy. I've read external cam QR skewers are the way to go for strength. Anyone got any views on this?
Now these would be ideal: http://www.ebay.co.uk/itm/M14-M18-M22-M27-M30-M33-Sump-ORing-Plug-Sealing-Bolt-Blanking-Plug-Rubber-Washer-/252928685968?var=&hash=item3ae3b97790:m:mro59zFQKdIjHHgBw7WyIxg
If I buy 20mm pipe that is 1.5mm thick that means ID=17mm.
If I buy an 18mm tap and buy the M18 heads, is 1mm =enough for the threads...
Maybe a dumb question but I don't know enough about taps. Thanks again guys.
Totally depends on the pitch of the thread. Standard M18 is 2.5mm pitch, 15.5mm ID.
So according to Wiki, thread depth is 0.866 x pitch.
Therefore 0.866 x 1.5 (pitch of end bolts in ebay link) = 1.299mm.
But if ID = 17mm, I'm only going to get 0.5mm each side with an 18mm tap which makes me think it will strip very easily...
And I can't find m19 bolts that are suitable plus I'd need at least a 22mm head diameter. Back to plan A...
Last update before I'm on the verge of being annoying. I have found 20mm alu pipe with 2mm walls which is perfect. Bought M18 sump plugs and an m18 tap. Fingers crossed...
I'd go M16, leaves a bit more material and it's a more common fixing size, you'll be able to get taps, bolts and washers easily...
5lab- if you're breaking your 55s I could be after the stanchions
Seems reasonable. Only thing I'll add is try to keep the tapped thread short so it sits inside the fork legs and you have a complete section where type tube leaves the forks and enters the hub.Last update before I'm on the verge of being annoying. I have found 20mm alu pipe with 2mm walls which is perfect. Bought M18 sump plugs and an m18 tap. Fingers crossed...
Sound advice mate but the inner diameter of my pipe is 16mm, I [b]have[/b] to use a M18 bolt.I'd go M16...
Having explored further, I've discovered that an M18 tap with 1.5 pitch needs 16.5mm hole (aluminium) and 17mm with steel. If i can't get the Alu to tap, think i will buy 20mm steel with 1.5mm walls.
Yeah buddy, am all over it. Sump plugs are only 12mm long so no problems with being longer than dropouts. Just hope they're long enough to take the torque.Seems reasonable...
Having explored further, I've discovered that an M18 tap with 1.5 pitch needs 16.5mm hole (aluminium) and 17mm with steel. If i can't get the Alu to tap, think i will buy 20mm steel with 1.5mm walls.
I'd like to know where you got that info. Maybe go up 0.1mm from aluminium to steel not a full 0.5mm. That would greatly reduce the actual thread depth. Might work but wouldn't be what I would do.
IAAE 😉
TBF it's only a pair of preload caps, once the fork clamps are nipped up the caps are doing very little.
You could probably get away with a pair of ~25mm OD washers/caps and a long old through-bolt of some sort... (edit- or a Rear QR as you suggested back up the page)
It might not be as pretty but saves you tapping that thinner walled axle.
I'd like to know where you got that info..
Certainly sir:
http://www.shender4.com/metric_thread_chart.htm
https://www.trfastenings.com/Products/knowledgebase/Tables-Standards-Terminology/Tapping-Sizes-and-Clearance-Holes
http://www.engineeringsupplies.co.uk/tapping-drill-sizes-i-15.html
http://www.stanleyengineeredfastening.com/sites/www.emhartamericas.com/files/downloads/spiralock-drill-size-charts.pdf
Not being a dick, but i did my homework 😀
Cookeaa - what you're suggesting was my plan A and it would be a hell of a lot easier than tapping. But it would be too easy, I'm a sucker for an engineering challenge and as nick pointed out - The horizontal clamping force may have to be addressed in case there is any play.
Not being a dick, but i did my homework
No saying you were 🙂
Just trying to be helpful as I've never come across anywhere that suggested using a drill that size for that thread. I'm sure, for this application, it would be fine though.
The little machine shop reference is to achieve only 75% aluminium/50% steel thread depth.
Stevied - hehe yeah man I know you were. The last link is probably the best and most comprehensive which says alu should be tapped into a 16.7 hole, doesn't say thread % though. Well spotted on the first link - I hadn't seen that. I guess I'm aiming for 75% as this seems to be standard?
For M18x1.5 in theory you'd drill a 16.5 hole but in practice you'd drill 16.7/8 as the strength gained is very little and it makes your taps last longer. How are you planning on making the end caps? I've always found diy internal tapping easy, but external tapping harder to get a nice finish.
Geforce - this is what I have gathered on my travels, though i was hoping i'd just try to tap the 16mm Hole and hope for the best.
All my research has said steel will tap nicely at M18/1.5 so i'm wondering whether to just get a steel pipe with 1.5mm walls. Could you please tell me why the taps will last longer if i was to drill 16.8 rather than 16.5?
This is what i've found for end plugs, they're basically perfect, head diameter of 23.5mm, 12mm thread length and have a rubber seal.
http://m.ebay.co.uk/itm/252926448053
Stevied - just reread your post. What does IAAE stand for and what would you do?
Thanks for all this input guys. I want to get it right and i'm hoping if i get it right i can throw some out to people who need em for 1\2 the price they cost retail.