HELP! Broken threads, can they be saved?

[snowjim]

Is M32 the same as 32mm? If so, such a thing cost about 2000 SEK, unfortunately doesn't seem like an option.

 

[richardtenggren]

It looks like the screw itself is intact and fine, but the problem is with the bicycle itself. So what you're saying is that a bottom tap is what you need? Can you get it to follow the inner threads that are intact while also cleaning up the outer edge? Are there such for 32 mm?

Hard to see in the picture, but does it look like different materials in the female and male threads? It can be difficult to guide it straight and in the same "track" if it's broken at the start, there are also thread files that fix female threads, though not the one at biltema.

Thread taps/dies are available in all sizes, I would think, come in different pitches, which is worth noting.

There are many thread standards. https://sv.wikipedia.org/wiki/Gänga

 

[Stefan1972]

M32 straight off is a rather coarse thread, so it's likely about a fine pitch in that case, and finding such a tap as well as a bottoming tap is likely minimal or will cost a fortune. If you happen to find one, it's guaranteed not to be a bottoming tap, and they certainly won't want you to cut it off either.........

I would probably determine the pitch and buy a thread file to clean up what I can and then hope that I can thread it decently and get it in. The threads in the cycle might hold up even if it's a bit tough.

 

[snowjim]

Hmm sounds like the only way out here is to try to get hold of a thread file for hongängor with the right pitch and then try to get the screw in as best as possible.

Any suggestions on where I can find the right thread file?

 

[snowjim]

This is how the exploded view looks and it's the front one that's causing trouble:

 

[Stefan1972]

it seems that there are still some spare parts available? Have you checked with those who sell them? If you get a new part, it might be significantly easier. Then you can use the old screw as a thread chaser if you can get it decent. Clean out the threads and then cut slots in it with a disc grinder like on a tap. That way, you can clean the threads with it to some extent.

 

[Norrhyttan]

Is M32 the same as 32mm? In that case, one of those cost about 2000 SEK, unfortunately it doesn't feel like an option.

You never listened to my suggestion to go to the local truck or construction machinery workshop? There, M32 is not a hopeless dimension. You don't have to own all the tools yourself.

 

[snowjim]

I took a couple of detailed pictures just when we got it home and before we started taking it apart for cleaning, and this is how the front screw looked then:


http://i.imgur.com/XFocjek.jpg

Dirty, of course, you can clearly see that tools have been used on the screw before. However, the previous owner claims they have never touched this screw!?

The gym owner whom I bought the bike from runs Wellnez Åhus and it's likely where the bike comes from, though it's strange to think it's worth taking advantage of a private person for 5500 kr. According to the owner's description, the product was supposed to be in mint condition, which I unfortunately cannot agree with. But it seems there's not much else to do but try to resolve the defect on my own

 

[Stefan1972]

You never listened to my suggestion to go to the local truck or construction machinery workshop? There, M32 is not a hopeless dimension. You don't have to own all the tools yourself.

No, but M32 fine thread is probably not a staple even in such workshops...........

 

[snowjim]

You never listened to my suggestion to go to the local truck or construction machinery workshop? There, M32 is not a hopeless dimension. You don't have to own all the tools yourself.

Yes, I did, but I haven't gotten there yet. I thought I'd first try to contact the contacts I have in car and bike workshops to see if they can help me. If there's no reasonable solution there, I'll proceed with your suggestion. Thanks!

 

[snowjim]

it seems that there are still some spare parts available? Have you checked with those selling them? If you can get a new part, it might be much easier. You can use the old screw as a cleaning rod if you can get it decent. Clean up the threads and then cut grooves in it with an angle grinder as if it were a thread tap. Then you can roughly clean the threads with it.

Yes, most spare parts are available, but replacing the frame is probably more expensive than buying a brand new one. New screws can be purchased; it's worth noting, however, that there is an identical screw at the back, so I might as well try with that one first. It doesn't look like any of the screws are damaged in the threads themselves, but sure, nothing is impossible.

What angle grinder and thread tap are you talking about? Where can I get hold of them?

 

[Stefan1972]

What I meant was that if you get hold of a new screw, then you have the old one left and can do whatever you want with it. If you then tidy up the thread with a file and make sure it's okay, and then take a cutting machine/grinder and grind four transverse grooves in the old screw, over the thread that is. Then your old screw will function as a cleaning tap. You can use it as a simple tap, usually it works well if you just need to clean a few threads. The grooves you grind provide space for chips and goo to collect just like on a regular tap.

 

[Mikael_L]

I have personally never used such a thread file, but if I had this problem, I would probably try. But be careful not to remove anything that should stay.

Chemical metal can be used to repair threads that do not have high strength requirements in use. But you usually want to be able to trace the thread with a tap afterwards, which with this dimension and probably fine-threaded - becomes a bit of a headache. And a thread file can only work if there is an existing thread to "follow."

 

[Janus82]

In the exploded view, it looks like the threaded part sits outside the frame and that everything is then covered by a plastic cap. It should be a fairly simple task to cut off the entire part with threads and weld on a new one. If it's a standard M32 thread, it's just a matter of welding on a nut. Once the plastic caps are on, no one will see the modification.

Contact a metal workshop or blacksmith, and they'll fix that part quite quickly.

 

[Paxman]

According to the owner's description, the product was supposed to be in mint condition, which I unfortunately cannot agree with. But it seems there isn't much more to do than to try to solve the defect on one's own

Since you bought the bike from a company, the Consumer Sales Act applies. Read up a bit on it and you will see that the gym cannot shift the problem onto you as a consumer.