Modifying a steerer from a clip headset

[Jonny69]

Hi folks, I'm having a bit of trouble laying my hands on a clip-type headset for a particularly old fork, so I've been looking at alternative options. I think I can probably convert it to to a conventional threaded headset but I thought I'd run it through you guys in case this isn't a good idea or if there are any other options...

Ok, so the clip headset has a collar (the 'clip') which slides over an unthreaded portion of the steerer at the top. The top race is part of the clip. There is a threaded nut at the top that pre-loads the clip onto the headset bearings, then it's locked off using a pinch bolt in the clip.

The steerer is therefore quite a lot longer than it would be in a normal threaded headset, but it does appear to be 25.4mm diameter, so 1". I was wondering if I could simply trim the steerer to length and thread it, then just use a conventional threaded headset? Is there anything wrong with doing this?

The only hitch I can see is that the head tube cups are brazed into the head tube i.e. not removable, so they would have to stay in place and maybe they aren't a conventional race diameter. I can easily measure this though, or if it's pretty close then use loose balls instead of caged.

Is there anything else I can do which isn't so drastic?

 

[keithglos]

Re:

Most head clips used 31/32 diameter for the clip and 56 tpi (check this).
The head lugs were castings which included a cup shape for inserted bearing rings.
Some used 1/8 balls, the lower race could be larger. Rarely used after the late 40s.

Keith

 

[Jonny69]

Cheers Keith.

I measured that bit up and the thread is ~25mm which is a little too big to be 31/32" (24.6mm), so I assumed it might be a worn 1" thread. As I said, the actual steerer tube is 1" so it'll thread to a conventional 1" x 25 tpi.

I think the key problem is actually going to be the top bearing races. The top race in the headtube (which I haven't tried to prise out to see if it is removable - but it could be just stuck in with old grease) is the wrong shape to match up with the threaded cup on a threaded headset. May have to go back to the drawing board on this...

Bang on with the date. It's a mid/late 30's lightweight frame.

 

[keithglos]

Re:

The head clips were made to fit 31/32 so that the clip would tighten on the stem easily. I can almost remember a 1inch headclip but I think it was italian, possibly on a track bike like Cinelli?

If the thread is finer that 24 tpi then it will be 31/32, if British.

If the inserted cups are 1/8 balls they will be compatible with the old roadster headsets of which millions were made. I used to sell these bearing rings for about 2d each.

Sunbeam for example used 3/16 balls in the lower race, but the bottom head lug was larger.

Keith

 

[COUPES]

Re:

What frame is it? Might be worth finding a clip type headset. They turn up on fleabay or look out for an old frame with a clip headset. If it's a worthy frame and fork then it would be a shame to ruin it.

Simon

 

[Jonny69]

Re: Re:

The head clips were made to fit 31/32 so that the clip would tighten on the stem easily. I can almost remember a 1inch headclip but I think it was italian, possibly on a track bike like Cinelli?

If the thread is finer that 24 tpi then it will be 31/32, if British.

Got it, cheers for the info. Definitely British and definitely finer than 24tpi.

If the inserted cups are 1/8 balls they will be compatible with the old roadster headsets of which millions were made. I used to sell these bearing rings for about 2d each.

That's interesting. I don't have the balls so I can't be sure, but I probably have a roadster headset like you described on my BSA and I do think I remember the threaded race on the top being a bit of a different shape to normal. I might pop it off and see if I might be able to adapt one.

What frame is it? Might be worth finding a clip type headset. They turn up on fleabay or look out for an old frame with a clip headset. If it's a worthy frame and fork then it would be a shame to ruin it.

Simon

It's a very snotty Parkes lightweight from about 1937. Lots of chrome, but it's more tatty than most people want so it'll never be worth much - and I just saw a clip (not a whole headset) go for £37 on eBay!

I've got a wanted ad in the wanted section here in case anyone has one. Don't need a NOS one, just a useable one will do!

 

[COUPES]

Re:

Lol I just got that one. I've seen Nos Chater lea ones go for £200! Prewar definitely worth saving. Brampton also made headclips.

 

[Jonny69]

^ Damn your eyes

 

[COUPES]

Re:

Have a word with bicycleboutique on ebay and see what he's has. Think he's in East Sussex. Sells alot of prewar bits. I need a chater lea headclip. Most of mine are prewar.

Simon