Drilling/threading a steel fork crown

Lumen

I have a new steel fork, rigid, for 700c wheels, but with disc tabs.

It has a threaded hole at the back of the crown, for a mudguard. I have fitted a mudguard, so the hole works.

I have a light like this:



I want to attach the light to the front of the crown. There is no hole.

I own an ordinary handheld drill, and a Dremel.

Ideally I'd like a threaded hole, or else I'm going to have to drill out the thread at the back and use a single long bolt. I don't like losing a thread for no good reason.

How difficult is it to put a threaded hole in a steel fork crown? What tools would I need? How much would a shop charge?

langdang

Lidl had a tap and die set recently I think. The "tap" is what you need to make a thread in a hole.

Keep_Her_Lit

Lumen wrote: »

How difficult is it to put a threaded hole in a steel fork crown? What tools would I need? How much would a shop charge?

A handheld drill will do fine for that job. I think it should be safe to drill that hole, since many fork crowns are drilled the whole way through as standard. PM me if you want a lend of the tap, handle and required drill bits - probably M5 or M6?

Lumen

Keep_Her_Lit wrote: »

A handheld drill will do fine for that job. I think it should be safe to drill that hole, since many fork crowns are drilled the whole way through as standard. PM me if you want a lend of the tap, handle and required drill bits - probably M5 or M6?

Many thanks, PM sent!

TinyExplosions

Lumen wrote: »

Many thanks, PM sent!

IS this for the hub geared, winter fantastic bike?

Lumen

TinyExplosions wrote: »

IS this for the hub geared, winter fantastic bike?

Yes. The build is proving a complete ballache somewhat of a challenge.

doozerie

Personally I wouldn't hold a drill free-hand while drilling that out. It's certainly doable but it can be tricky to hold a drill steady enough that you keep the bit from walking, drill the hole perpendicular to the surface, etc. By preference I'd use a pillar drill if you have access to one or else a portable drill stand that fits your drill. I have a pillar drill which is not at all portable or I think I still have a portable stand that you can borrow if I can find it (it's cheap and clunky but helps).

If doing it free-hand I'd start with a smaller bit on a slower speed just to create enough of a hollow for the larger drill bit to sit into so that it doesn't wander.

TinyExplosions

Lumen wrote: »

Yes. The build is proving a complete ballache somewhat of a challenge.

What problems are you having? I know you alluded to issues with the 11speed IG hub, but I'd be interested to know some more details of it!

What frame are you using? The Pompetamine?

Keep_Her_Lit

doozerie wrote: »

Personally I wouldn't hold a drill free-hand while drilling that out. It's certainly doable but it can be tricky to hold a drill steady enough that you keep the bit from walking, drill the hole perpendicular to the surface, etc. By preference I'd use a pillar drill if you have access to one or else a portable drill stand that fits your drill. I have a pillar drill which is not at all portable or I think I still have a portable stand that you can borrow if I can find it (it's cheap and clunky but helps).

If doing it free-hand I'd start with a smaller bit on a slower speed just to create enough of a hollow for the larger drill bit to sit into so that it doesn't wander.

A light tap with a centre punch will locate the drill for the pilot hole and eliminate any risk of it wandering off. A pillar drill (or portable drill stand) would improve the precision, agreed. However, there shouldn't be any problem keeping a handheld drill within a couple of degrees of perpendicular which I think will be fine for a hole used for fitting accessories. A second pair of eyes can be useful in that situation, to verify that the drill angle is there or thereabouts before starting the hole.

Lumen

TinyExplosions wrote: »

What problems are you having? I know you alluded to issues with the 11speed IG hub, but I'd be interested to know some more details of it!

What frame are you using? The Pompetamine?

Yes, the Pompetamine.

Most of the problems are down to either my ignorance of disc brakes and geared hubs, or the complexity of squeezing disc brakes, mudguards, chain case, and 35mm slicks into a confined space.

Off the top of my head, issues are:

- Lack of documentatoon from Shimano about 11sp Alfine and dynamo hub dimensions, making spoke length calculations a bit of a punt (fix: cross fingers for Holyboy's wheelbuilding skills).

- No mounting point for front light (fix: drill and tap it)

- Front disc caliper interfering with front mudguard stay (fix: epic bodge with super long bolt, will post pic when build is done)

- BB7 6-bolt disc rotors not compatible with Shimano centrelock hubs (fix: buy an adaptor)

- Disc caliper snug to rear frame, blocking access to adjustment bolt (will probably just make setup harder).

- Inteference between chain case and Alfine bash ring (fix: remove bash ring, get shorter chainring bolts from Holyboy).

- Lack of clearance between Thorn accessory bar and handlebar (fix: maybe buy a more extreme angled accessory bar)

- Rear mudguard mounting point is perpendicular to that required by SKS mudguard sliding mount (fix: remove sliding mount, drill mudguard).

- Insufficient chainstay length for chain chase (fix: modify chain case).

- Inability to find pitlock-compatible seat clamp in 29.8mm size (fix: will probably use solder to fill in the seat post and saddle bolt heads).

TinyExplosions

Lumen wrote: »

Yes, the Pompetamine.

...list of problems...

Why didn't you just buy it made up?

Still, sounds like a fun project!

Lumen

TinyExplosions wrote: »

Why didn't you just buy it made up?

Because AFAIK neither On One nor anyone else sells an 11sp Versa-equipped bike yet, and if they did it wouldn't have the dynamo hub, mudguards or fancypants rims I want.

TinyExplosions

Lumen wrote: »

Because AFAIK neither On One nor anyone else sells an 11sp Versa-equipped bike yet, and if they did it wouldn't have the dynamo hub, mudguards or fancypants rims I want.

That's an acceptable reason then... carry on.

What rims you going for? This could be a nice build when (if!) it's finished

niceonetom

Have you summoned the courage to tot up what this project will have cost when finished? I'm curious.

Lumen

TinyExplosions wrote: »

What rims you going for?

Stans ZTR Crest 29er.

niceonetom wrote: »

Have you summoned the courage to tot up what this project will have cost when finished?

No. It will be a big number, though I'm telling myself that I'm being parsimonious by using a £230 steel frameset rather than some custom unobtanium curation.

TinyExplosions

Lumen wrote: »

Stans ZTR Crest 29er.



No. It will be a big number, though I'm telling myself that I'm being parsimonious by using a £230 steel frameset rather than some custom unobtanium curation.

Ah, this is the 29" abomination I was hearing about... no wonder you're having problems

I'd have stuck to 700c myself, bish bash bosh, job done -easy like!

Lumen

TinyExplosions wrote: »

Ah, this is the 29" abomination I was hearing about... no wonder you're having problems

I'd have stuck to 700c myself, bish bash bosh, job done -easy like!

700c is 29", right? Or else I'm completely screwed.

TinyExplosions

Lumen wrote: »

700c is 29", right? Or else I'm completely screwed.

My bad... I thought there was a slight difference between the two.

Carry on with your monstrous plan, and god speed!

Coronal

Lumen wrote: »

700c is 29", right? Or else I'm completely screwed.

I always saw it referred to as 28". It's probably fine...

Holyboy

Lumen wrote: »

700c is 29", right? Or else I'm completely screwed.

700c, 28", 29er its all the bloody same, seems like you have had a busy day!

cdaly_

Keep_Her_Lit wrote: »

A light tap with a centre punch will locate the drill for the pilot hole and eliminate any risk of it wandering off. A pillar drill (or portable drill stand) would improve the precision, agreed. However, there shouldn't be any problem keeping a handheld drill within a couple of degrees of perpendicular which I think will be fine for a hole used for fitting accessories. A second pair of eyes can be useful in that situation, to verify that the drill angle is there or thereabouts before starting the hole.

In this case, I would use a small drill through the hole at the back of the fork crown to start the hole at the front. Once that breaks through, you can drill from the front at the correct size.

That said, given that the plan is to tap the hole, you want to be very sure it's perpendicular...

Holyboy

BTW, I'd have a look at options before drilling anything!
Headset mount or even bolted where fender is with a mount that runs under the fork crown, if there's room of course!
Drilling would be my VERY last resort.

http://www.bumm.de/produkte/mehr/scheinwerferhalter.html

Lumen

Holyboy wrote: »

BTW, I'd have a look at options before drilling anything!
Headset mount or even bolted where fender is with a mount that runs under the fork crown, if there's room of course!
Drilling would be my VERY last resort.

http://www.bumm.de/produkte/mehr/scheinwerferhalter.html

None of the headset mounts listed on that page fits the B&M IQ Cyo. I also looked here, and the only option that I could see was on the fork leg, which is too low and looks hideous.

Are there any off-the-shelf products like your "mount that runs under the fork crown"? Would have to be thin as I don't want to lose mudguard clearance.

What's your concern with drilling?

Holyboy

Drilling holes just makes me think of Homer Simpson and his speed holes! But I suppose it may end up being the best solution, unless a custom mount could be fashioned:)