Options for fixing over filed axle dropout?

[LewTwo]

If you are filing the existing dropout with an adhesive or filler, I'm assuming that would not be strong enough on its own minus the plate? I guess the two just both add fortification.

Not to my way of thinking. As someone previously mentioned, you have created 'stress risers' with those sharp corners. You need to reduce the stress at those points. Bonding additional material to the base material that bridges those corners reinforces it ... thus reducing the stress.

And can I confirm you are suggesting to attach that plate on the inside of the dropout as in the picture? I would then need to make sure I have enough clearance.

One thing that I did not mention before is that picture looks to be the wrong way round to me ... I did not realize it was the "inside" of the frame. What you need is a flat surface to which to bond the new material. Good news is that you have a steel frame. That means you can spread the stays apart if needed (not recommended in the case of aluminum frames). My concern would then be the spacing between the derailurer and the sprockets. If you do both left and right sides of the frame then the spacing between the disk rotor and the caliper becomes an issue as well. Ideally this type of addition would be done on the 'outside' of the dropouts ... but someone mentioned that you have recesses ????

But as Markz said I suppose the plate and the original dropout would need to line up perfectly so that the force is on both.

Take a long 10mm bolt and put a wrap of wax-paper round it. After the epoxy has set, drop the bolt out.

One thing I'm wondering about is the option of 'refilling' the existing dropout, which the mechanic mentioned and some others.

Does this mean anything to you guys? I don't really know what it would be, but I'm imagining it as a solution which uses the original dropout by adding back the filed metal with welding, rather than an exterior plate?

That is the ideal solution, if you can find someone to do it properly with either steel welding (preferred) or bronze brazing. Otherwise this may a more practical solution .... and yes nothing wrong with extending the new metal a bit along the stays as long as it will not create any fitment or interference problems.

I once got a vintage Miyata 610 bicycle for a very good price. The original owner had an accident and broke the rear derailleur mount off. My solution was simple: Replace the rear hub with an Internally Geared Hub (which I prefer anyway). The point being, consider all the alternatives and choose the most practical.

If not for the pandemic then you could make a quick trip up to Thailand with the frame. Find any small bicycle shop in Pattaya or Phuket. They could fix it and have it back to you in a day or so as good as new .... of course they might add a 'noodle cart' to one side as well. :lol:

 

[MaximilianMM]

If you are filing the existing dropout with an adhesive or filler, I'm assuming that would not be strong enough on its own minus the plate? I guess the two just both add fortification.

Not to my way of thinking. As someone previously mentioned, you have created 'stress risers' with those sharp corners. You need to reduce the stress at those points. Bonding additional material to the base material that bridges those corners reinforces it ... thus reducing the stress.

And can I confirm you are suggesting to attach that plate on the inside of the dropout as in the picture? I would then need to make sure I have enough clearance.

One thing that I did not mention before is that picture looks to be the wrong way round to me ... I did not realize it was the "inside" of the frame. What you need is a flat surface to which to bond the new material. Good news is that you have a steel frame. That means you can spread the stays apart if needed (not recommended in the case of aluminum frames). My concern would then be the spacing between the derailurer and the sprockets. If you do both left and right sides of the frame then the spacing between the disk rotor and the caliper becomes an issue as well. Ideally this type of addition would be done on the 'outside' of the dropouts ... but someone mentioned that you have recesses ????

But as Markz said I suppose the plate and the original dropout would need to line up perfectly so that the force is on both.

Take a long 10mm bolt and put a wrap of wax-paper round it. After the epoxy has set, drop the bolt out.

Thanks, I'll look into this.

One thing I'm wondering about is the option of 'refilling' the existing dropout, which the mechanic mentioned and some others.

Does this mean anything to you guys? I don't really know what it would be, but I'm imagining it as a solution which uses the original dropout by adding back the filed metal with welding, rather than an exterior plate?

That is the ideal solution, if you can find someone to do it properly with either steel welding (preferred) or bronze brazing. Otherwise this may a more practical solution .... and yes nothing wrong with extending the new metal a bit along the stays as long as it will not create any fitment or interference problems.

Right. So I'd be asking a welder to 'fill in' (with TIG stainless steel?) and then cut (although I could do that myself I suppose) back to the required shape. Is there a particular way of describing this other than the way I have just done? I'm not too confident of what to ask for currently!

Also, I've spoken to a couple of panel beaters/automotive who do welding but can't do this. The last one I spoke with said a panel beater won't generally be able to do this, and that I need a fabricator. I don't quite understand why that is, but I guess I'll try and find one of those.

I once got a vintage Miyata 610 bicycle for a very good price. The original owner had an accident and broke the rear derailleur mount off. My solution was simple: Replace the rear hub with an Internally Geared Hub (which I prefer anyway). The point being, consider all the alternatives and choose the most practical.

If not for the pandemic then you could make a quick trip up to Thailand with the frame. Find any small bicycle shop in Pattaya or Phuket. They could fix it and have it back to you in a day or so as good as new .... of course they might add a 'noodle cart' to one side as well. :lol:

:lol: Noodle cart wouldn't be too bad I suppose.

 

[LewTwo]

So I'd be asking a welder to 'fill in' (with TIG stainless steel?) and then cut (although I could do that myself I suppose) back to the required shape. Is there a particular way of describing this other than the way I have just done? I'm not too confident of what to ask for currently!

Also, I've spoken to a couple of panel beaters/automotive who do welding but can't do this. The last one I spoke with said a panel beater won't generally be able to do this, and that I need a fabricator. I don't quite understand why that is, but I guess I'll try and find one of those.

panel beaters/automotive??? Is that an automotive body repair person ??

Actually with welding or brazing all you need is the corners/top of the drop out filled in (unless you filed it too wide as well). You do not need tig or stainless. Oxy-Acetylene, Arc, Mig or Tig will work. You just need enough fill material so that you can grind/file the slot to the proper shape and width.


The added material should be the full thickness of the dropout.
Any more material 'inside' the 10mm slot is just going to have to be ground/filed away ... such is life.

A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.
Someone bronze brazing will just clean the surfaces (wire brush and solvent) and then add filler material.

 

[MaximilianMM]

So I'd be asking a welder to 'fill in' (with TIG stainless steel?) and then cut (although I could do that myself I suppose) back to the required shape. Is there a particular way of describing this other than the way I have just done? I'm not too confident of what to ask for currently!

Also, I've spoken to a couple of panel beaters/automotive who do welding but can't do this. The last one I spoke with said a panel beater won't generally be able to do this, and that I need a fabricator. I don't quite understand why that is, but I guess I'll try and find one of those.

panel beaters/automotive??? Is that an automotive body repair person ??

Yep! I guess that's an Aussie term.

Actually with welding or brazing all you need is the corners/top of the drop out filled in (unless you filed it too wide as well). You do not need tig or stainless. Oxy-Acetylene, Arc, Mig or Tig will work. You just need enough fill material so that you can grind/file the slot to the proper shape and width.
Screenshot X1.jpg
Screenshot X2.jpg
The added material should be the full thickness of the dropout.
Any more material 'inside' the 10mm slot is just going to have to be ground/filed away ... such is life.

A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.
Someone bronze brazing will just clean the surfaces (wire brush and solvent) and then add filler material.

Thank you SO MUCH for doing these pictures. I really do appreciate it, I'll be taking them with me to the welder.

'A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.'

Any chance you could translate this for me? Do you mean before welding, and for what purpose?

I found a fabricator who quoted me $300 AUD but I'm hoping I can get it done for less than that.

 

[Hillhater]

Even at “only” $300, i would rather just put that money into another frame to convert.!
Those drop outs will most likely be forged , and any heat/welding on them will weaken them

 

[MaximilianMM]

Even at “only” $300, i would rather just put that money into another frame to convert.!

Those drop outs will most likely be forged , and any heat/welding on them will weaken them

I don't want a new frame, sentimental value and I've come this far.

Why do you think welding would weaken rather than strengthen the drop outs? That's a bummer if so and not something anyone else has raised.

If this is true, then perhaps brazing is a better option as it won't affect the source metal of the dropout?

 

[LewTwo]

Thank you SO MUCH for doing these pictures. I really do appreciate it, I'll be taking them with me to the welder.

'A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.'

No Worries ....

'A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.'
Any chance you could translate this for me? Do you mean before welding, and for what purpose?

Well now that is a bit of a challenge.

First sketch is the raw dropout (Status quo).
Second sketch is the dropout (full grind before welding - very difficult to draw).
Third sketch is the finished dropout (after grinding/filing slot to shape).

The welder may not need to do any grinding at all or maybe just the top section (if you did not file the slot more than 10mm wide). Basically it is a tight space even if the welder is using a 1/8 inch (3mm) diameter electrode. The chamfer gives a bit of elbow room to get the tip of the electrode in from the side versus down the throat.

Those drop outs will most likely be forged , and any heat/welding on them will weaken them

The tube material is Reynolds 631 ... same alloy elements as Reynolds 853.
Both are Air-Hardening. Reynolds 631 adds work hardening for about 10% more strength.
I am assuming (infamous last words) that the dropouts are a similar alloy.

Even at “only” $300, i would rather just put that money into another frame to convert.!

Can't argue that point. One might want to peruse the Australian E-Bay site.

 

[MaximilianMM]

Thank you SO MUCH for doing these pictures. I really do appreciate it, I'll be taking them with me to the welder.

'A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.'

No Worries ....

'A welder may likely want to grind away a 30-45 degree taper from the center of the thickness.'
Any chance you could translate this for me? Do you mean before welding, and for what purpose?

Well now that is a bit of a challenge.
Screenshot Z0.png
First sketch is the raw dropout (Status quo).
Second sketch is the dropout (full grind before welding - very difficult to draw).
Third sketch is the finished dropout (after grinding/filing slot to shape).

The welder may not need to do any grinding at all or maybe just the top section (if you did not file the slot more than 10mm wide). Basically it is a tight space even if the welder is using a 1/8 inch (3mm) diameter electrode. The chamfer gives a bit of elbow room to get the tip of the electrode in from the side versus down the throat.

Understood! Thanks again for the excellent drawings, that really makes it clear

Those drop outs will most likely be forged , and any heat/welding on them will weaken them

The tube material is Reynolds 631 ... same alloy elements as Reynolds 853.
Both are Air-Hardening. Reynolds 631 adds work hardening for about 10% more strength.

I am assuming (infamous last words) that the dropouts are a similar alloy.

Right, so if I understand correctly, so long as the drop outs are the same material as the tubes then welding won't weaken them.

Maybe brazing is safer and still strong enough though if I can't be sure. After all the entire point of the exercise is to be secure in the strength.

Even at “only” $300, i would rather just put that money into another frame to convert.!

Can't argue that point. One might want peruse the Australian E-Bay site.

Yes, maybe. I can't bring myself to admit defeat yet though. It might come down to the price I can get for welding/brazing.

 

[ZeroEm]

Just a thought, if you going to go to all the trouble to have a welder work on it. Why not design new drop outs for the motor. Cut the old ones off and weld the new ones on. Could be clamping so you don't need torque arms or plates.

 

[MaximilianMM]

Just a thought, if you going to go to all the trouble to have a welder work on it. Why not design new drop outs for the motor. Cut the old ones off and weld the new ones on. Could be clamping so you don't need torque arms or plates.

I'm sure that's a good idea but I don't have the skills or know how to do that.

 

[ZeroEm]

Take a look at this, 4th post down.
APL's V4 Cruiser build

Just some thing to think about.

 

[Hillhater]

Those drop outs will most likely be forged , and any heat/welding on them will weaken them

The tube material is Reynolds 631 ... same alloy elements as Reynolds 853.
Both are Air-Hardening. Reynolds 631 adds work hardening for about 10% more strength.
I am assuming (infamous last words) that the dropouts are a similar alloy.

No matter what the steel alloy is, if it is forged (?) any serious heat, like welding, can alter the micro structure and grain allignments that give forging their strength.
And , weld heat can also change the base chemistry of the alloy in and around the weld area.
Having said that , i am sure a good fab shop welder could do a very effective job, but they are not the guys you find in auto bodyshops or your average bike shop.!

 

[ZeroEm]

They even say it in the Movies.

Cold Rolled Steel.

 

[LewTwo]

No matter what the steel alloy is, if it is forged (?) any serious heat, like welding, can alter the micro structure and grain allignments that give forging their strength.

Must be why they do not weld them to the tubes to begin with.

 

[MaximilianMM]

Take a look at this, 4th post down.
APL's V4 Cruiser build

Just some thing to think about.

Nice! Think that might be one for the future.

I've found a welder who is going to do it for $130. Will let you know how it goes.

 

[stan.distortion]

No matter what the steel alloy is, if it is forged (?) any serious heat, like welding, can alter the micro structure and grain allignments that give forging their strength.

Must be why they do not weld them to the tubes to begin with.

Take a closer look, a well designed forging or casting will have more weld area than the cross sectional area of whatever's being welded to it (a slash cut or slot for example). When there's no alternative, a pipe butt welded to a fitting for example, the casting will be larger diameter than the pipe. Everyone goes crazy for billet parts but well designed castings of the same material are far stronger and forgings stronger still, the granular structure of a metal makes a big difference but that's lost when re-melted in a weld.

 

[MaximilianMM]

Those drop outs will most likely be forged , and any heat/welding on them will weaken them

The tube material is Reynolds 631 ... same alloy elements as Reynolds 853.
Both are Air-Hardening. Reynolds 631 adds work hardening for about 10% more strength.
I am assuming (infamous last words) that the dropouts are a similar alloy.

No matter what the steel alloy is, if it is forged (?) any serious heat, like welding, can alter the micro structure and grain allignments that give forging their strength.
And , weld heat can also change the base chemistry of the alloy in and around the weld area.
Having said that , i am sure a good fab shop welder could do a very effective job, but they are not the guys you find in auto bodyshops or your average bike shop.!

This is from the Reynolds website:

What's the best method for welding frames?
For many years the only recommended way to assemble a frame was by fillet brazing or brazing with lugs, and this was the way 531 frames were constructed. When Reynolds introduced 753, due to the nature of the material, these tubes needed to be low temperature silver soldered.

We now have a new generation of materials in 525, 725, 631, 853 and 953 steels. All of these can be brazed, but the most popular method of assembly is by TIG welding. (on 853 we do recommend that gear fittings etc are silver soldered onto the tubes).

There are many filler wires that can be used on 525/725/631/853 like ER-70S-6.

For materials like titanium, special welding equipment and procedures are required to ensure that oxygen does not contaminate the weld areas. The 953 range is also subject to recommended practice for stainless steels in addition to the skills needed for fabricating with thin wall tubes. On 953, we only have tested the stainless 17-4PH grade wire although other wires may work.

-------

So they are specifically designed to be welded it seems.

It seems TIG is preferred. My welder said he does MIG, so I need to establish whether that's an important difference.

 

[stan.distortion]

Can he braze it instead? MIG would be ok, no worse than TIG if regular filler rods are used. TIG generally gives a better finish but a good welder with a MIG can do a nice, clean weld on there. Seems like the alloy is a significant concern so brazing would be the best option if he can do it imo but there's plenty of weld area there, maybe ask if he can try a test weld first, tack something to it and see what happens when breaking it off, he'll know what to look for.

 

[MaximilianMM]

Can he braze it instead? MIG would be ok, no worse than TIG if regular filler rods are used. TIG generally gives a better finish but a good welder with a MIG can do a nice, clean weld on there. Seems like the alloy is a significant concern so brazing would be the best option if he can do it imo but there's plenty of weld area there, maybe ask if he can try a test weld first, tack something to it and see what happens when breaking it off, he'll know what to look for.

You think the alloy/welding is a concern despite the Reynolds being made to be suitable for welding? Why would that be?

My reading indicates TIG welding gives a stronger, cleaner and more precise outcome than MIG, so that seems preferable. Given its a small target area and I'm not sure of the welder's skills, I feel TIG is safer.

It's also what the Reynolds site mentions.

Brazing seems like a strong safe option as well, I'll see if it's possible. Thanks.

 

[stan.distortion]

Can he braze it instead? MIG would be ok, no worse than TIG if regular filler rods are used. TIG generally gives a better finish but a good welder with a MIG can do a nice, clean weld on there. Seems like the alloy is a significant concern so brazing would be the best option if he can do it imo but there's plenty of weld area there, maybe ask if he can try a test weld first, tack something to it and see what happens when breaking it off, he'll know what to look for.

You think the alloy/welding is a concern despite the Reynolds being made to be suitable for welding? Why would that be?

My reading indicates TIG welding gives a stronger, cleaner and more precise outcome than MIG, so that seems preferable. Given its a small target area and I'm not sure of the welder's skills, I feel TIG is safer.

It's also what the Reynolds site mentions.

Brazing seems like a strong safe option as well, I'll see if it's possible. Thanks.

You're unlikely to find a TIG (or MIG) welder who'll get you in ER-70S-6 filler material and not charge you more than the frame is worth, less than one in a thousand welders would ever be using anything other than general purpose materials. Generally there's not a whole lot of difference between the strength of TIG and MIG, TIG is slower and more precise whereas MIG gets the job done much faster but can be messy and that's where most of the strength difference lies, heats faster, cools faster and therefore more brittle. That's not really an issue for what you need, far more weld can be applied than needed so a slightly more brittle weld wont make any significant difference, it's never going to be subjected to the kind of forces that would cause it to fail.

EDIT: Oops, ER-70S-6 is a common filler material, should be no issues with the alloy but I'd still do a test weld beforehand.

 

[MaximilianMM]

Can he braze it instead? MIG would be ok, no worse than TIG if regular filler rods are used. TIG generally gives a better finish but a good welder with a MIG can do a nice, clean weld on there. Seems like the alloy is a significant concern so brazing would be the best option if he can do it imo but there's plenty of weld area there, maybe ask if he can try a test weld first, tack something to it and see what happens when breaking it off, he'll know what to look for.

You think the alloy/welding is a concern despite the Reynolds being made to be suitable for welding? Why would that be?

My reading indicates TIG welding gives a stronger, cleaner and more precise outcome than MIG, so that seems preferable. Given its a small target area and I'm not sure of the welder's skills, I feel TIG is safer.

It's also what the Reynolds site mentions.

Brazing seems like a strong safe option as well, I'll see if it's possible. Thanks.

You're unlikely to find a TIG (or MIG) welder who'll get you in ER-70S-6 filler material and not charge you more than the frame is worth, less than one in a thousand welders would ever be using anything other than general purpose materials. Generally there's not a whole lot of difference between the strength of TIG and MIG, TIG is slower and more precise whereas MIG gets the job done much faster but can be messy and that's where most of the strength difference lies, heats faster, cools faster and therefore more brittle. That's not really an issue for what you need, far more weld can be applied than needed so a slightly more brittle weld wont make any significant difference, it's never going to be subjected to the kind of forces that would cause it to fail.

EDIT: Oops, ER-70S-6 is a common filler material, should be no issues with the alloy but I'd still do a test weld beforehand.

Thanks very much for the info.

I'm interested why you say it won't be subjected to the kind of forces that would make it fail?

It's going to be the frontline resistance against the axle torque, surely the strength is critical. Am I missing something?

 

[stan.distortion]

Imagine an open ended spanner, you're trying to more or less the same thing here, something that's resisting being spread apart. If you took a length of bar and welded two lugs to it to do the same job you'd need a lot of bracing, the lugs are being pushed apart and the weld would be at the weakest point. That's not what you're doing here, it's pretty much the same as welding two spanners together along their length, the welds would be subject to a rotational force rather than a bending force and you'd have a much longer run of weld. That make sense?
EDIT: Come to think of it, the heads of a couple of cheap 10mm spanners would probably be your easiest option, they're made from a chrome vanadium alloy and it welds ok.

 

[MaximilianMM]

Imagine an open ended spanner, you're trying to more or less the same thing here, something that's resisting being spread apart. If you took a length of bar and welded two lugs to it to do the same job you'd need a lot of bracing, the lugs are being pushed apart and the weld would be at the weakest point. That's not what you're doing here, it's pretty much the same as welding two spanners together along their length, the welds would be subject to a rotational force rather than a bending force and you'd have a much longer run of weld. That make sense?
EDIT: Come to think of it, the heads of a couple of cheap 10mm spanners would probably be your easiest option, they're made from a chrome vanadium alloy and it welds ok.

To a point! The gap is no doubt my lack of knowledge rather than your explanation.

I must emphasise I am starting from a base of zero technical knowledge in this area, so thank you for bearing with me.

I think what I'm struggling with at a basic level is that I've been told that the right angle file has created a critical point of weakness and potential failure in the dropout. So as it stands it will be subjected to forces that could cause it to break.

Therefore, my reasoning tells me that the strength of whatever filling is used to mitigate that must surely be critical in reversing that weakness.

So I can't quite follow why a more brittle weld would reliably be enough to change the dropout from its current status as a point of potential failure to totally secure as before.

 

[stan.distortion]

You're still planning on adding an additional plate to re-enforce the dropout, right? If not and you're just planning on filling in where you've filed too deep then you're definitely going to need torque arms imo, welding will improve the situation but it won't be as strong as the original dropout no matter how well done, material had to be removed to increase the slot width so it will be weaker.

 

[MaximilianMM]

You're still planning on adding an additional plate to re-enforce the dropout, right? If not and you're just planning on filling in where you've filed too deep then you're definitely going to need torque arms imo, welding will improve the situation but it won't be as strong as the original dropout no matter how well done, material had to be removed to increase the slot width so it will be weaker.

Yes, I'm going to be fitting two Grin torque arms as well.

Not planning to add a plate, just filling.