Grease nipple on Rudge Montague folder

[fastpedaller]

Does anyone know the thread size for the grease nipple for a montague folder? It's definitely tapered (which makes it difficult to measure?).
Thanks in anticipation

[rjb]

This link may help you to identify it.

https://greaseextensionhoses.com/grease ... ification/

[fastpedaller]

Thanks....... I'm sure I have a thread gauge somewhere
Failing that I'll offer up an m6 and see if the thread is finer (on the nipple) - I suspect it's a 1/4 x 28 tapered. next thing is to buy one!
ETA ... or it could be a unf which is 26TPI .... Hmm not much difference (but critical I'm sure!)

[Brucey]

is the old one blocked? Even if the grease nipple is in good condition you will need a proper high pressure grease gun to force grease into that fitting.

I have never had to remove mine so I don't know what size it is. I have a stash of both M6 taper thread and 1/4" taper thread nipples somewhere. Each one is designed to be fitted into a parallel threaded hole, so at the base of the taper on the nipple, the male thread is definitely going to be oversize. However once a nipple has been fitted into the hole the top part of the thread is reformed, so potentially a 1/4" threaded part will start in a M6x1 tapped hole that has had a tapered thread nipple fitted to it previously.

You can check the thread pitch on the nipple against an M6 x 1 screw, but over that short distance it won't be possible to tell the difference between 1mm and 26tpi pitch.

FWIW the hexagon on mine (which is a black one which is different from yours to some extent) measures 7.09mm. This strongly suggests it is meant to be a 9/32" hexagon and therefore the nipple threading is probably 1/4" x (something). However if the hexagon measures 7mm it proves nothing; 1/4" threaded nipples with 7mm hexagons on them are made.

[edit; I have just measured an M6 nipple and as expected it has a 6.97mm hexagon on it, and threads that taper from 5.75mm to 5.99mm diameter on it (cf a typical M6x1 threaded bolt which measures 5.90mm OD on the threaded parts).]

cheers

[fastpedaller]

Thanks Brucey. It wasn't blocked - just corroded. Being a fiddler I decided to undo it ......and of course it rounded off so ( Like MM I've started so I'll finish) I just had to put the long handle water pump pliers on it and mash it up some more to take it off
Passing a useful farming supplies retailer today (about the only useful shop around here!) I nipped in to see what nipples they had, and alas they'd run out of 1/4 UNF and 1/4 BSF, but had a 6mm taper one which cost me 54p! They did have a rather nice stainless steel 5mm one (over £2 so I didn't indulge until I've identified the thread) They assure me the other sizes will be replenished soon, so we'll see what fits. I had about a dozen grease nipples in a drawer in my garage, all but 2 were elbow ones (which maybe would have ended up in a suitable orientation) but too large a thread - another was the correct thread but very long. I'll get there

[fastpedaller]

Revisiting this a couple of hours ago, I found that the 'elbow' grease nipples fir the thread! I should have tried one - they just looked too big so I hadn't
Anyway, this gives a better aim for the grease gun - the size is 1/4 UNF (as verified by a setscrew.) I then set to with the grease gun, to find it (the greasegun) was blocked with solidified grease. A while later it was all cleared and refilled, and the frame was attacked in earnest and pumped until all the brown muck came out of either end, and clean grease revealed itself. Next job was to check the tracking (which needs adjustment) and find the grub screw is seized! I left it soaking during a leisurely lunch - if it won't move I can always carefully grind the end away with a small oilstone until I get to the correct point. Ah the fun of cycle maintenance - I'm just very thankful to the manufacturers of latex gloves after today's messy doings.

[fastpedaller]

The grub screw moved easily - just shows the penetrating power of cutting fluid! On to the bottom bracket, my intention was to remove it to check everything is ok (at least) and to see if there's any possibility of fitting a sealed one (mainly because I want to fit a single chainring, shorter length crakset). The RH cup wouldn't budge (2-flats campag style). I tried the nut & bolt method, and stripped the thread on the nut. Hmm - eventually found another, larger (14mm) nut and bolt, but still no joy. In desperation I put the (very thin) flats in the bench vice, not expecting to get a result and hey-presto it undid ....... I must have loosened it with the nut and bolt The old bb revolved well, but once removed it was clear the campag type grease was pretty solid, so I'm pleased I removed it.
Surprise was that a spare, previously used Shimano un53 bottom bracket went in! Montague maybe changed the later frames to accommodate a sealed bb bearing? It must be close though, because when I took it out again to ensure I had some waterproof grease in the thread, I noticed the label was all chewed up . The old bb was indeed 132mm, and the new is 124. Difference on the RHS is 6mm. It looks like my chosen cranks (spa 160mm) will fit ok, but until I've taken them of my Pompino to try, the jury is out.... it will be a close thing!

[Brucey]

I think they did make some changes on the later frames then; there is no way a UN53 would go in an earlier frame...

cheers