Can I reuse my drain screw...?

[Dave Whittle Thorn Workshop]

Thorn recommend 611, SJS use 641,

Rohloff/Thorn/SJSC recommend 511 if your going to re-use.

Loctite 641 is seal glue and is used for the hub shell and cap seals.

In practice bottles of 511 are expensive, we just use a new coated plug every time:

- The threadlock builds up as you drive it into the hub and prevents it going to far into the hub.
- It stops the plug rattling loose
- It stops the plug siezing in (the plug and shell are too different metals)

[wheezy]

Just to add my name to the cavalier list...

I re-use the screw, and don't use thread lock.

[triaesthete]

  I reuse mine too but I put a a dab of blue hylomar on the top couple of threads only and then place a piece of insulation tape over the top. That way it can't fall out and any leak via the threads will show as the tape lifting. It also means it stays clean underneath so I can do an oil change without washing the bike first.

Julk's point about locking and sealing compounds getting into the hub is the most pertinent though. PTFE tape fragments will be particularly detrimental to the selector operation so go careful with it out there.

A new one every time smacks of consumerism gone mad to me.
Little things count
Ian

[Andre Jute]

Same here. Reuse the screw. I bought a kit that didn't come with a new screw but didn't worry about it.
Good point about a long term tourer taking 1.
I think I would take 2 and pack in separate bags. But that's just me.

You're not concerned about the extra weight?  

Don't! You never know when there will be an obsessed (or new) roadie reading this, and getting sleepless nights about that little grub screw's one gram.

I can just see his anguished post: "I've recently bought a platinum-plated titanium sheathed carbon-monofilament (hand-rubbed on the thighs of Mongolian virgins) TheresOneBornEveryMinute, and can't see the Rohloff grub screw in titanium at SJS. Am I looking in the wrong place?"

[David Simpson]

I can just see his anguished post: "I've recently bought a platinum-plated titanium sheathed carbon-monofilament (hand-rubbed on the thighs of Mongolian virgins) TheresOneBornEveryMinute, and can't see the Rohloff grub screw in titanium at SJS. Am I looking in the wrong place?"

If you can't find a titanium Rohloff grub screw, then just drill out your existing one.  A simple 37/154" drill through the middle of the screw will save you 0.0073 grams, and the leaking oil will also save 0.08 grams per drop.  (My Dad used to drill out his water bottles to save weight.)   

- Dave

P.S. Everything in this post is in jest.  Do not drill out the grub screw!

[Rockymountain]

I'd like a platinum-plated titanium sheathed carbon-monofilamen grub screw.......but can't seem to find one one the SJS website 

[Andre Jute]

I'm laughing so helplessly, I can't even google it for you.

BRING BACK DRILLIUM!

[alcyst]

you need a magnetic floor  as we have in the trade

Magnetic floor & steel toe safety boots, something is beginning to make sense here......

That & the perpetual resistance training means the Thorns Works Team should be formidable, but only on fixes.

[triaesthete]

Go eco, lightweight and handcrafted: put a cork in.

[Andre Jute]

...put a cork in.

I thought for a moment you were running for election to Captain of the Topic Pohleese.

[David Simpson]

I have been guilty of side-tracking this topic, so I will try to make amends now.

Below, I am summarizing the ideas so far.

There are three choices:
1. Use a new screw.
2. Re-use the old screw, using Loctite or some other thread seal.
3. Re-use the old screw, without thread seal.

The important points to remember are:
1. ensure the screw is tight enough so that it doesn't work loose while riding (hence the use of thread seal), but not too tight
2. ensure that excess thread seal does not get into the hub internals.

The original question was "can I reuse my drain screw?", and I believe the general consensus is "yes, you can, provided that you remember the important points that listed above". As for using thread seal or not, I don't see a general consensus here.

I have only needed to do one oil change on my Rohloff, since my bike is just over a year old. But going forward, I think I will use new screws. I doesn't make sense for me to buy a bottle of Loctite just for this purpose, since I would only need one drop every year! (Although I already have other bottles of different types of Loctite, but I'm not sure if they are the correct type.) Also, the new screws are very inexpensive. When I do my next order from SJS, I will simply add 10 new screws to my order, and not worry about this problem for another decade.

- Dave

[mickeg]

Rohloff/Thorn/SJSC recommend 511 if your going to re-use.

Loctite 641 is seal glue and is used for the hub shell and cap seals.

In practice bottles of 511 are expensive, we just use a new coated plug every time:

- The threadlock builds up as you drive it into the hub and prevents it going to far into the hub.
- It stops the plug rattling loose
- It stops the plug siezing in (the plug and shell are too different metals)

Dave, thanks for the comment on dissimilar metal corrosion.  I did an oil change a couple weeks ago, did not use Loctite.  But the possibility of corrosion has convinced me to pull the screw out and put a bit of Loctite on it.

I read some time ago a post which cautioned that when using loctite, or similar, it was very important not to get any into the hub where it could be very detrimental to operation.
julk.

I will make sure I put it on the screw threads instead of the shell threads.

[alcyst]

Rohloff/Thorn/SJSC recommend 511 if your going to re-use.

Loctite 641 is seal glue and is used for the hub shell and cap seals.

In practice bottles of 511 are expensive, we just use a new coated plug every time:

- The threadlock builds up as you drive it into the hub and prevents it going to far into the hub.
- It stops the plug rattling loose
- It stops the plug siezing in (the plug and shell are too different metals)

If I have mistaken seal glue for sealant and put a bit on a re-used drain screw do I need to worry or do anything? Is it a petrol/diesel type problem or a gravy mix/instant coffee type problem?

[Dave Whittle Thorn Workshop]

Seal glue is a non locking sealant, so it should stop leaks but wont stop it undoing.

[Andre Jute]

It is very important that you don't insert the drain screw too deep into the Rohloff hub shell, because it may interfere in the operation of the gearbox.

One-half to one millimeter of the drain screw should ideally stand proud of the surface of the hub shell, and its top must never be any deeper than level with the surface of the hub shell.