Facing to increase stack height

[drossall]

I've seen a couple of references to facing the head tube to gain a bit of stack height. I've got a frame with a set of replacement forks (1" threaded) on which I need to gain a few threads (there's about one thread left for the top nut after fitting the top race, so the former won't even catch). Therefore this seemed a good plan. My (very good) LBS weren't willing to try the job, and felt that it would damage the tool.

Their point was that facing was normally to remove paint and so on. Even if it worked, it would take ages to remove the amount that I was suggesting. I hadn't really considered frame material, so I began to wonder whether it was because this was a steel frame (but you wouldn't really put a threaded headset in alloy?)

The threads here and here are talking about Bromptons, which are definitely steel!

I've only ever needed to get a frame faced once, so I'm no expert. Should I just give up and resume my search for new forks?

[mzjo]

Ask a frame builder. Your LBS might have a relatively cheap tool that is, as they say, only good for scraping the paint. The frame builder will have a tool meant to remove metal.
A couple of years ago I made the mistake of asking my LBS to thread down a fork before I shortened it. They did but the resulting job was pretty rough and, thinking about it afterwards I came to the conclusion that their die was only meant for cleaning up existing damaged threads, not cutting fresh ones. I should have asked the local frame builder instead.

[loadsabikes]

I am just North of Peterborough and have the required tooling if it's not too far to travel.
Happy to help you out.

[drossall]

Not too far - I'm in Hitchin. Thanks for the offer.

[Biggsy]

I found it hard work to remove much material from my titanium head tube with a Cyclus tool.

Pedantic point: facing REDUCES stack height.

Have you already got the shortest headset that will fit?  Tange Passage?

[drossall]

My headset is a Shimano 105, so quite low stack height. There's probably a shorter one, but I have a few 105 bits put by, so keeping to one brand across bikes has some benefits.

In any case, the kind offer from loadsabikes should resolve the issue.

I realise that the aim is to reduce the required stack height, but from my perspective that's gain. It was a slightly short-hand way of writing, I suppose

[rogerzilla]

Argos did it for me - about 2mm.  Required to fit a Chris King 2Nut to a Brompton.

[Tewdric]

Another vote for getting a Tange Passage - it will gain you 3mm or so which sounds like it would solve the problem.

<edit>. Here..

http://www.spacycles.co.uk/products.php?plid=m2b0s115p1095

[Paul Rainbow]

Yes I think I would always advise getting a headset with a stack height that avoids removing excessive amounts of material from the frame. I seen 5 - 10 mm taken off a frame so its a not a problem but can look a bit weird.

You can never put it back! (without a costly new head tube)

Remember you can also mill down the fork crown seat. These are often much deeper than needed on steel forks and 5mm may be saved here. 

If you really cant find a lower stack height headset then the minimum amount of removal of top and bottom of head tube and fork crown seat may be the best option.

[drossall]

Well many thanks to loadsabikes. I had a very pleasant trip up today. I enjoyed chatting over the facing work, and I was even offered lunch.

Best of all, I now have a frame with forks that fit. Just need to find time to build it up

Here's another one for the YACF community thread.

[rogerzilla]

Resurrecting this one, the usual issue with facing to reduce stack height is that good steel frames have either lugs or reinforcing rings at the top and bottom of the head tube, giving you a lot of material to remove.  Bromptons don't; it's a design fault which eventually (we're talking a decade of daily use, maybe) leads to ovalisation of the head tube and a loose lower headset cup which is expensive to sort out properly, since the lower tube needs building up with brass and reaming, at the very least.

Therefore a Brompton is easier to face because there is much less material to remove - just the head tube itself, with no lugs or reinforcement.

[rogerzilla]

Just to add, now I have the tools I have done this on a Harry Quinn where I wanted another 1.5mm for a cartridge headset and a brake hanger.  Easy enough - the Cyclus tools go through steel very efficiently*.  Best to take 0.5mm off the fork crown seat and 0.5mm top and bottom of the head tube, rather than just attacking one surface and making it look a bit wrong.

This is the crown after cutting down from JIS to ISO.  It's rather neat.

20180821_121614 by rogerzilla, on Flickr

*they're not just for removing paint: new handbuilt frames always need cutting and facing, and metal WILL need to be removed.  Factory frames may be milled or turned on big machines these days.

[Brucey]

if you take more than a small amount from a fork crown you will find it very difficult to fit light brackets and even some brakes.

It is nearly always the best idea to get a headset that fits the bike rather than to bully the frameset into accepting a given headset.

cheers

[rogerzilla]

Lots of 1990s forks out there cut right down for 32mm Shimano cup and cone headsets, which are no longer made.  Tange Passage is often the only option, and it's a bit meh.

Fork crowns vary a lot.  I have one here that doesn't have a crown seat as such - the race sits on the flat crown itself - but there's masses of clearance around the brake.

[drossall]

Well, I'm pleased to say that I've still got the original bike from this thread, and it has held up just fine.

It hasn't seen as much use as I hoped because, a year after the thread started, I was made redundant and, since then, I've been commuting into London. That means a folder. After a few years of using a Dahon, that broke, and I took another trip up to see loadsabikes and buy his Brompton

Still, it's good to have the original bike, which was originally badged as a 501 Marlboro, still running.

[rogerzilla]

Was it advertised by a long-dead-from-lung-cancer cowboy?

[drossall]

Hah! It came from an obscure bike shop. I've forgotten where. It was quite a nice blue originally.