Timberwolf / Aurora Disc brake / axle drilling question- help Please!

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Jul 8, 2022
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So the axles on the Timberwolf are 5/8". I need to fix the disc brakehub (solid type as shown in the tutorials) to the axle, but I'm not sure the axle is strong enough for a 1/4" thru bolt as is used on the 3/4" axle in some other models.

The gear cluster is fully supported inside the second bearing, on the left side, but the disc brake hub is between the two bearings on the right side of the rear swing arm assembly.

I did not follow the plans exactly which have you fabricate up a thick washer which gets welded to the axle- I was wanting to be able to break down the rear axle assemblies if needed.

What methods will work in this situation short of welding the brakehub to the axle? What size hardware if any did you use?
 
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Haddn't thought of that one! A longitudinal groove in the axle is not all that hard to do, But do you think that a smaller thru hole like 3/16" would work and be safe enough or I had also thought of tapping the set screw holes out to 5/16" , scratching the axle, with a file and forcing some epoxy with the large set screws into the space between the axle and the hub. (hydraulic pressure) I like JB weld for something like that and it's extremely strong or maybe brazing the hub on? - then it would also be removable if you wanted to ever replace the bearings. I will also have a front brake as well, so not super critical to even have a rear brake at all! I even thought of making the hub out of aluminum for the lighter weight. (no brazing or welding possible then!) This thing is not going to win any races I don't think. ! LOL!
 
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Haddn't thought of that one! A longitudinal groove in the axle is not all that hard to do
But one inside the adaptor is !
3mm roll pin or 8.8 bolt should suffice and easily changed should you snap it ?
I will also have a front brake as well, so not super critical to even have a rear brake at all!
The plans show a rear brake and no front brake for a reason ?
A single front brake is dangerous !
With a single front wheel the moment you lock that up you have NO steering OR braking , it will just get you to the scene of the crash !

Paul
 
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But one inside the adaptor is !
3mm roll pin or 8.8 bolt should suffice and easily changed should you snap it ?

The plans show a rear brake and no front brake for a reason ?
A single front brake is dangerous !
With a single front wheel the moment you lock that up you have NO steering OR braking , it will just get you to the scene of the crash !

Paul
Paul- That 3mm roll pin is certainly a good idea. They don't sell metric roll pins over here, but there are close equivalents like 1/8". The bolt idea is also good if I can find a high grade one in that size,

I might still try the JB weld idea first as it is the easier way to go for now. You can always loosen up epoxy with a little heat and there is no material removed from the axle at all.
 
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"Industrial applications experience talking".
Drilling straight trough the middle of a shaft/axle removes the most material and weakens it even a lot more compared to the simplicity.
But if you go for that idea, roll pins, not bolts. And if you can't avoid bolts, make sure the threaded part doesn't get any sheering force.

Also, once you aquired the materials and tools to broach a keyway, it isn't that bad.

But it goes against the spirit of being an Atomic Zombie. Specialist tools are just that, specialist tools.
 
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Maddox- I could probably re mount the axle on my milling machine and cut a slot for a keyway, but I wanted to get the brackets for the brake caliper mounted ASAP. I got the new 140mm brake disk mounted to the hub, and the hub now has a 1/8" thru hole for a roll pin. I don't know if I wlll ever drill the axle with a thru hole, but it was a lot easier to add the hole in the hub now rather than later.

If the JB weld glue works after some vigorus testing of the rear brake, I think i'll just leave the axle in it's original un drilled condition. I'm hoping that the smaller 140mm brake disk will not grab the axle and stop it too suddenly. After all, it's only stopping one wheel. If the glue fails then I can always get more serious with fasteners of some type, and I still have the front brake to help out.

I sure wish that photos were easier to upload on here! Somebody remind me what is the proceedure?
 
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I too am looking at shaft-to-other connections.
For my application with a 12mm silver steel axle I am contemplating a 4mm key.
I was a bit surprised to see that for a 4mm keyway they recommend you DO NOT use a 4mm cutter but rather a smaller one and then make your keyway minimally oversize with that.
I guess it is because a 4mm 4-flute cutter will cut too much wider than 4mm due to manufacturing tolerances and mill run-out.
This makes things a bit more complicated I think.
I suppose you can mill a central 3mm trench at 2mm depth and then take the sides out with further passes until your key is a "snug" fit and then stop, but you run the risk of going off-centre with your keyway.
I think I will try a 4mm 4-flute on a single pass and see how slack/tight the slot is for the key on a bit of scrap first. After all, we aren't NASA or NASCAR. :)
 
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Ok pictures :- Some help

Lets start at the beginning what wheels are you using and how are they fastened to the axles ?

Most people would consider a single disc brake on the rear somewhat lacking , if for example you or your trike or carried load were to be a bit on the lardy side you still run the risk of locking the single braked wheel up ?

How are you attaching the gear cassette to the shaft ?

Paul
 
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Sagle, Idaho USA
I too am looking at shaft-to-other connections.
For my application with a 12mm silver steel axle I am contemplating a 4mm key.
I was a bit surprised to see that for a 4mm keyway they recommend you DO NOT use a 4mm cutter but rather a smaller one and then make your keyway minimally oversize with that.
I guess it is because a 4mm 4-flute cutter will cut too much wider than 4mm due to manufacturing tolerances and mill run-out.
This makes things a bit more complicated I think.
I suppose you can mill a central 3mm trench at 2mm depth and then take the sides out with further passes until your key is a "snug" fit and then stop, but you run the risk of going off-centre with your keyway.
I think I will try a 4mm 4-flute on a single pass and see how slack/tight the slot is for the key on a bit of scrap first. After all, we aren't NASA or NASCAR. :)
Please let me know how you are going to cut the groove in the axle if your wheel is already welded to one end of it? That was my situation and even though I have a milling machine, the table is not ( I think) capable of cutting a slot for a keyway that is only a few inches from the wheel. This was the main reason for thinking of trying the epoxy trick to hold on my brake disk hub. I have not yet finished making the deraileur brackets and that fact is holding up my progress/experiments for the brake hub.

It's a bit slow going with the Timberwolf design for the lack of detailed pictures for the deraileur and brake caliper. When I get mine dialed in I will put some pics on here if possible for future builders. I have a tentative solution for the disk brake now, but the deraileur is still a week or two away from being welded on. I can't find any good pictures showing the entire deraileur setup anywhere, so I'm trying to copy a regular bike that uses the same deraileur. I found that the deraileur hanger mounting point is 1.25 inches below and 3/8 inches behind the axle on a regular bike and about an inch outboard of the smallest sprocket of the freewheel.

I made a plywood template that simulates the 1.25 inch drop and 3/8" setback and drilled the two holes for the 5/8" axle and the hole for the mounting bolt in the template, but I found that the bolt that I was using to hold the deraileur to the hanger bracket was interfereing with the space where the chain will go. I think the solution for that will be to use the same bolt that held the deraileur to the original bike frame by tapping a 10mm hole in the mounting bracket I'm fabricating. Then the inside face of the bracket will be flat and and the fastener will act exactly like the original did on the conventional 21 speed bike. I also found that the derailer is supposed to be able to pivot on the mounting bolt. This is not mentioned in the plans and I think it may be a mistake to ignore that fact.
 
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It's a bit slow going with the Timberwolf design for the lack of detailed pictures for the deraileur and brake caliper. When I get mine dialed in I will put some pics on here if possible for future builders. I have a tentative solution for the disk brake now, but the deraileur is still a week or two away from being welded on. I can't find any good pictures showing the entire deraileur setup anywhere, so I'm trying to copy a regular bike that uses the same deraileur. I found that the deraileur hanger mounting point is 1.25 inches below and 3/8 inches behind the axle on a regular bike and about an inch outboard of the smallest sprocket of the freewheel.
On the Timber Wolf the plans show the derailleur mounting pages 149 - 152 and clearly show they are NOT using the same derailleur you are try to use.
On the Aurora the plans show the derailleur mounting pages 159 - 163 and clearly show they are NOT using the same derailleur you are try to use.

I think the solution for that will be to use the same bolt that held the deraileur to the original bike frame by tapping a 10mm hole in the mounting bracket I'm fabricating. Then the inside face of the bracket will be flat and and the fastener will act exactly like the original did on the conventional 21 speed bike. I also found that the derailer is supposed to be able to pivot on the mounting bolt. This is not mentioned in the plans and I think it may be a mistake to ignore that fact.
I don't think it is fair to criticise the plans when you are using a different derailleur and find it does not fit !

Paul
 
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St. Louis Mo USA
To mount the break adapters on my Timber Wolf, I drilled and tapped 3 holes radially around the adapter, then positioned it on the axle, then tightened the set screws to produce a location mark. After removing the adapter I could easily drill the holes about 1/4" deep. No need to drill through. I used 3/4" axle instead of the 5/8" but it should work on the 5/8" as well. I also made the wheels removable, so I would have better access to working on the axle.
 
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On the Timber Wolf the plans show the derailleur mounting pages 149 - 152 and clearly show they are NOT using the same derailleur you are try to use.
On the Aurora the plans show the derailleur mounting pages 159 - 163 and clearly show they are NOT using the same derailleur you are try to use.


I don't think it is fair to criticise the plans when you are using a different derailleur and find it does not fit !

Paul
Paul- I don't mean to criticise the plans- No one could publish plans to cover all the possibilities, So I was looking for help and ideas to cover the situation I have and could not make the plans work with what I had on hand. That being said, my deraileur is almost identical to the one in the plans, and I tried to follow the plans to the letter, but some aspects of the plans made me hesitate and try to improve, not only in my work process, but in the final outcome which is what I will be living with for years to come.

The Timberwolf
On the Timber Wolf the plans show the derailleur mounting pages 149 - 152 and clearly show they are NOT using the same derailleur you are try to use.
On the Aurora the plans show the derailleur mounting pages 159 - 163 and clearly show they are NOT using the same derailleur you are try to use.


I don't think it is fair to criticise the plans when you are using a different derailleur and find it does not fit !

Paul
Paul, Please don't take my request for help as criticism of the plans. That is not my intention. But anything can be improved on if it is done right. I am a trained machinist and trike enthusiast, and I have built my own delta trike from scratch which - if I may brag a little- quite a bit more sophisticated than anything on AZ. However, it took me 10 years to perfect the design and required a set of jigs and a tubing bender to fabricate which I no longer have.

So the situation now is that the wife wants something to ride and I thought it would be nice to build her a Timberwolf. This design has a lot of good features and the square tubing makes not having jigs and a tubing bender a non- issue.

I really did not have any questions until I got to the disc brake and deraileur brackets. This is where you are dealing in 3 dimensions and with a new (for me) disc brake parts that do not seem to have enough detail in the plans so that you can fabricate something in one try that will work. I started by chance with a 160mm disc and the identical caliper you see in the plans, but that combination puts the caliper too high above the frame to mount in any reasonable fashion that I could think of. So I bought a 140mm disc, and it was then possible to make everything fit, although I did make my front mounting point straddle the entire gap in the frame where the caliper sits to avoid any possible vibrations or hiccups later on. I wish I could figure out how to post pics on here as I am pretty proud of how it came out,

My disc hub is still not fastened to the axle, but the caliper itself is securely bolted down on some welded brackets that should be trouble free.

None of my brackets for the disc brake look anyting like the plans, but that is personal choice and not criticism in any way.

The deraileur mounting was another situation that needed some help. There were some problems that could have materialized down the road if not addressed, and don't take this as criticism, but why would you weld your deraileur to the bike frame?

If you ran over something and the deraileur gets bent up, you are now in for some frustration and time spent trying to find another deraileur, cut it up, weld on another extension and so on.

And in the plans he says - "if you want to see how to mount your deraileur - look at an upright bike" - So I did, and there were some differences from the plans once again. I just copied my old upright bike for the X, Y, and Z offsets - comparing the rear axle center to the deraileur mounting pivot bolt center- which is different from the plans and made my own desigh for a bracket that fits and is much stiffer and makes the deraileur removable with one bolt. Not only that, but the ends of the axle still touch for alignment purposes and do not interfere with the deraileur in any way. The shifting should also work as original because the offsets are all copied 100% from the upright bike.

So now I have the deraileur and disc brake modified to my personal preference, I hope some day to be able to post pics of these changes here and I think at least some builders will appreciate the difference. I also hope to see a lot more examples of all the designs being completed and rideable in the builder's gallery- I only saw two Timberwolf examples there? Are there more? And I want to hear from the builders about how well they work! It is all well and good to see plans, but it is another thing entirely to hear from the people who are actually building and RIDING their creations!
 
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First upload it to a picture hosting site such as imgur.com. There are many others. From there you can get a direct link to it and then paste that link into the box that appears when you click the 10th icon from the left above where you type (the one that looks like a picture).

 
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Paul- I don't mean to criticise the plans- No one could publish plans to cover all the possibilities, So I was looking for help and ideas to cover the situation I have and could not make the plans work with what I had on hand. That being said, my deraileur is almost identical to the one in the plans, and I tried to follow the plans to the letter, but some aspects of the plans made me hesitate and try to improve, not only in my work process, but in the final outcome which is what I will be living with for years to come.
Yes you are correct the plans will help someone with no knowledge of how to build one , however they can always be improved on.
It always amazes me when someone turns up on the forum with a working machine despite never seeing one [ or a commercial one ] in the flesh before hand.

I really did not have any questions until I got to the disc brake and deraileur brackets. This is where you are dealing in 3 dimensions and with a new (for me) disc brake parts that do not seem to have enough detail in the plans so that you can fabricate something in one try that will work. I started by chance with a 160mm disc and the identical caliper you see in the plans, but that combination puts the caliper too high above the frame to mount in any reasonable fashion that I could think of. So I bought a 140mm disc, and it was then possible to make everything fit, although I did make my front mounting point straddle the entire gap in the frame where the caliper sits to avoid any possible vibrations or hiccups later on. I wish I could figure out how to post pics on here as I am pretty proud of how it came out,
Clueless on mounting disc brakes myself

The deraileur mounting was another situation that needed some help. There were some problems that could have materialized down the road if not addressed, and don't take this as criticism, but why would you weld your deraileur to the bike frame?

If you ran over something and the deraileur gets bent up, you are now in for some frustration and time spent trying to find another deraileur, cut it up, weld on another extension and so on.
Agree my mantra is modify as few parts as possible , I don't want to be stuck anywhere because I cannot walk into a bike shop and pick up a replacement for a broken part , this also extends to avoiding hydraulic brakes , yes they work faultlessly for years then when they do fail the parts are no longer available to fix them.

And in the plans he says - "if you want to see how to mount your deraileur - look at an upright bike" - So I did, and there were some differences from the plans once again. I just copied my old upright bike for the X, Y, and Z offsets - comparing the rear axle center to the deraileur mounting pivot bolt center- which is different from the plans and made my own desigh for a bracket that fits and is much stiffer and makes the deraileur removable with one bolt. Not only that, but the ends of the axle still touch for alignment purposes and do not interfere with the deraileur in any way. The shifting should also work as original because the offsets are all copied 100% from the upright bike.
I think there is much leeway to the rear mech mounting , if you think the end stops seems to allow for almost another 5 sprockets of width and I have seen a bike today with a rear cassette with a 52T sprocket ! rear mech looked pretty standard except for the fact the frame hanger was much longer !
Sram 52T



Are there more? And I want to hear from the builders about how well they work! It is all well and good to see plans, but it is another thing entirely to hear from the people who are actually building and RIDING their creations!
A flaw in the internet where you can see someone has built a new/novel design and then there is absolutely '0' follow up as to whether it works or not.

Paul
 
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First upload it to a picture hosting site such as imgur.com. There are many others. From there you can get a direct link to it and then paste that link into the box that appears when you click the 10th icon from the left above where you type (the one that looks like a picture).


[/QUOT Thanks! I will try and get some shots put up soon.
 
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