Loctite on soft aluminium thread? (Airwings suspension post)

[Galactic]

Last year I treated myself to an Airwings suspension post (it was one of the few sus posts that fit my diameter), but before I'd even got the saddle in the right position, I'd managed to overtighten the steel bolt and strip the threads in the thingamijig that holds the saddle rails. I had tried to avoid this by being very careful with the tightening, but the saddle kept loosening itself when the bolt was done up just a tad less.

I've ordered a replacement for the bit with the stripped thread, and am obviously keen to repeat my mistake. Would something like Loctite help keep the bolt in place without having to do it up so tight that I risk stripping threads again?

For those who needs to see which thingamijig I'm talking about, it's the bit marked Aufnahme Bohrung on this page: https://shop.airwings-systems.de/produc ... c131239277, the thread in question being in the middle hole.
That piece mount onto the top of the Airwings Comfort1 Plus, as seen here: https://shop.airwings-systems.de/produc ... p457527562.

All suggestions and advice gratefully received!

[Jdsk]

Does/could the end of the bolt come out on the other side of the threaded receiver?

Does the manufacturer suggest a torque setting?

Jonathan

[Galactic]

Does/could the end of the bolt come out on the other side of the threaded receiver?

No, it doesn't go all the way through. The top of the post is in the way.

Does the manufacturer suggest a torque setting?

5Nm. As far as I can guess/feel, I only did it the offending bolt up to about 3Nm, but I've now acquired a torque measuring allen key thingy to make sure I don't overtighten again.

[Jdsk]

Thanks.

Do they say anything about use of lubricant or antiseize or threadlocker compound to accompany that torque setting?

(I'd clean the female thread and run a bolt gently in and out of it. And then use the recommended torque and any stuff that accompanies that setting.)

Jonathan

[Galactic]

Thanks for the advice.

Do they say anything about use of lubricant or antiseize or threadlocker compound to accompany that torque setting?

No, the handbook just states that every bolt should be tightened to 5Nm and don't overdo it because it won't make it any tighter, but may damage the saddle rails or the post.

Normally I'd dab a bit of grease on to avoid the bolt seizing over time, but I didn't do that last time (probably because I was still doing all the micro-adjustments to the saddle position).

I suppose now I have a torque-measuring allen key, if I do strip the threads at <5Nm I can at least complain.

[Jdsk]

Thanks.

Another thought: Could you put a steel threaded insert into the one that's stripped?

Jonathan

[Galactic]

Another thought: Could you put a steel threaded insert into the one that's stripped?

Ooh, never thought something like that might exist. I did ream it out a bit and try to cut a new thread, but the point on my die was too long and I couldn't cut more than one thread in the space, so that didn't work.

I've already ordered replacement bits, but if I do strip the threads again I should look at a threaded insert. Would I just drill out the hole to the right size and insert it like a rawl plug?

[Jdsk]

Another thought: Could you put a steel threaded insert into the one that's stripped?

Ooh, never thought something like that might exist. I did ream it out a bit and try to cut a new thread, but the point on my die was too long and I couldn't cut more than one thread in the space, so that didn't work.

I've already ordered replacement bits, but if I do strip the threads again I should look at a threaded insert. Would I just drill out the hole to the right size and insert it like a rawl plug?

Yes, but AIUI the different types have slightly different methods of insertion. There are experts here who know more than me about which would be best...

Jonathan

[rjb]

Can you drill it out, retap a size larger and use a corresponding sized bolt?

[Galactic]

Yes, but AIUI the different types have slightly different methods of insertion. There are experts here who know more than me about which would be best...

Thanks Jonathan. Good to know I have another option if I break things again!

Can you drill it out, retap a size larger and use a corresponding sized bolt?

I tried that, but the hole is only about 5mm deep, and the point on my tap is about 4mm, which meant I could only cut one rotation before the tap bottomed out. It was very frustrating!

[alexnharvey]

A full tap set well have taps with less lead in. Known as second or bottoming taps will cut nearly to the bottom of a blind hole.

A helicoil or timesert could be a good option.

[rjb]

you need a plug tap or use an appropriate bolt with saw cuts along the thread to resemble a tap. Take care if using this as you will need to go slowly and reverse it every quarter turn to clear the swarf.

[531colin]

https://uk.farnell.com/c/fasteners-mech ... -metric=m5

Have a look at M5 riv nuts linked above.....there are all sorts, and numerous suppliers...if you have a suitable shop locally, it would help to actually get a look and feel of the things, but just from the website, I would be inclined to try drilling out the stripped thread to insert (say) the fifth one down; it has a small (countersunk?) flange, and I reckon you could countersink the back of the stripped alloy part and epoxy one of those riv-nuts in place....trim off the other end if its too long.

Edit...I see above its a blind hole....any reason not to drill the hole all the way through to the other face of the part, and countersink the riv-nut in? the bit we are looking at is just to clamp the saddle rail one side, and the saddle angle adjustment is separate??

[Barrowman]

There are a myriad of Loctite Products. Need to decide what metals you are dealing with . The stuff you find in V brake screws is designed for steel to steel. Probably not ideal for Alloy or carbon fibre.
I used to go into an excellent supplier who would confirm what you were using it for and give you the right stuff.
Long gone sadly.

[Galactic]

Thanks for all the responses so far - very helpful information. I'm making notes as we go along in case I can't find this thread to strip (geddit?) when I need it.

I've already ordered the new parts so right now my mind is on how best to avoid stripping the thread on the new chunk of aluminium. If that does happen again I think my best bet would be one of the inserts that 531Colin and Jdsk have recommended. I thought about drilling all the way through, but that would interfere with being able to adjust the angle of the saddle, so the only other option would be to tap a new thread. But seeing as I don't have the appropriate tap (perhaps a metalworking neighbour might, mental note to ask), and the new thread will be just as likely to be stripped (since the soft alu block is still the same as before), the inserts may well be the best option. But that's only IF the thread strips on this new bit of alu that should be arriving in the post after Eostre.

In the meantime, any tips about avoiding thread stripping, over than be careful and keep below 5Nm? Would Loctite (or similar) be an option for when I screw the bolt just tight enough to hold the saddle rail (ie a half-turn or so more than finger tight), with the gunk making sure it stays that tight and doesn't loosen as soon as the saddle experiences various forces from my nether regions?