Pilot . P-40 Warhawk

[SkyknightJohn]

Now for a question:

The head tube is 32.7 mm I.D., standard on these older frames.

Modern 1-1/8” threadless headsets are press fit for a 34.0 mm cup.

I have the die tool to cut & face the headtube for an EC34 headset. I would lose 1.3mm of 5.3mm wall thickness (0.65/side of 2.65mm/side) leaving it at a wall thickness of 2mm (or 0.078”).

That’s about the same wall thickness as headtubes I’ve bought raw for frame-up building.

Think this would work fine? Has it been done before?
Would it remain safe?
(I know there a some conversion headsets out there @ 32.7mm.)

(~edited for typos & math)

 

[LukeTheJoker]

Now for a question:

The head tube is 32.7 mm I.D., standard on these older frames.

Modern 1-1/8” threadless headsets are press fit for a 34.0 mm cup.

I have the die tool to cut & face the headtube for an EC34 headset. I would lose 1.3mm of 5.3mm wall thickness (0.65/side of 2.5mm) leaving it at a wall thickness of 2mn (or 0.078”).

That’s about the same wall thickness as headtubes I’ve bought raw for frame-up building.

Think this would work fine? Has it been done before?
Would it remain safe?
(I know there a some conversion headsets out there @ 32.7mm.)

If I am reading right, the current wall thickness is 2.5mm and you would be removing .65mm?
1.85mm wall is fairly thin for a headtube, but I have seen that and thinner on some bikes.

If you are worried you could cut two 12mm (1/2") sleeve rings to weld outside the headtube to add strength back.

 

[Captain Awesome]

If you are worried you could cut two 12mm (1/2") sleeve rings to weld outside the headtube to add strength back.

 

[SkyknightJohn]

Corrected my late night bad math a little in the post above.

I kind of hate posting both metric and imperial measurments, but so many of the materials/parts are listed as either one or the other, so I end up converting for my own clarity...

>> if math makes your head tube hurt, you may want to skip this next part <<

The current wall thickness is 2.65mm and the die would cut the cup portion down to 2mm. Looking at Nova Cycle Supply, most head tubes are 1.0 or 1.1mm. Of course they're Chromoly. In past builds, I've opted for less expensive plain tube 1.5" x 0.083" as head tube material. 0.083" = 2.1mm wall thickness. 1.5" x 0.083" leaves an I.D. of 1.334" or 33.88mm. Cutting for the 34mm bearing cup removes 0.12mm or 0.06mm/side, leaving a wall thickness of 2.04mm.

>> End of the Math <<

So, between what is commonly sold, and what I've done in the past, I feel that a 2mm wall thickness at the bearing cup would be enough & safe. Whether I make that irreversible change to the frame in order to use a modern sealed bearing headset and a different/better fork, I still have to decide.

 

[OddJob]

Sounds like you'll be fine.
Just my .02 mm's.

 

[SkyknightJohn]

 

[LukeTheJoker]

View attachment 95008
View attachment 95010
View attachment 95009

Firefly reference?

 

[SkyknightJohn]

Yessir. Kaylee can be my mechanic any day!

 

[kingfish254]

Hard to be a good CWC. Getting incorrect tanks to fit and look right is tough. You will quickly find out that there are more differences than similarities.

I think I may have a spare cwc tank like the one that rustygold showed. I will check tomorrow.

 

[SkyknightJohn]

Hard to be a good CWC. Getting incorrect tanks to fit and look right is tough. You will quickly find out that there are more differences than similarities.

I think I may have a spare cwc tank like the one that rustygold showed. I will check tomorrow.

Thanks KF! I've been mulling it over and would hate to modifiy a perfectly good tank to the point of no return. Of course, I'm considering modifying a frame to the point of no return, so, incosistent logic. On that point, home again after a work trip, should have some update later tonight or tomorrow.



Yes. Yes it is!

 

[Glen]

Happy birthday

Can't beat the Beatles

Glen.

 

[SkyknightJohn]

My fork selections. The new Surly disc (1-1/8”, L), the original, then the BMX style (Rt).

Head tube before & after Reaming & Facing for the 1-1/8” fork. Still plenty of material wall remains. They built them thick back then.

Pressed the headset and I like the look. Better proportion than the fatter fork and a nice curve.

Is that a long steerer tube or is it just happy to see me?
15”.
I might need to buy a few more spacers!
Or cut it down. <— yeah, that one.

 

[LukeTheJoker]

Nice work on the reaming!
What tool did you use?

 

[Chad T]

Great build. Love the modern parts on the vintage bike scenario.

Nice work on the reaming!
What tool did you use?

That does look good! Lot's better than the last one I did with files and some emory cloth taped to a socket on a drill..

 

[SkyknightJohn]

Nice work on the reaming!
What tool did you use?

I used the middle tool, a Cyclus Head Tube reamer/facer (dies for both standard 1” & 1-1/8” headsets). Right tool is a seat tube reamer for 27.2mm pins, also Cyclus. Left is the Park Tools headset/BB cup press. Funny, it’s the only one without blue.

My bike fanaticism path went like: e-bikes > they don’t make a good ebike frame > I can do better > need to learn to weld > need special tools > collect underpants > ... “ ___ “ ... > profit!
> hmmm... no profit? > old bikes are cool > RRB forum > Build offs are fun!

Bought about one expensive tool per year along the way. Tough on a budget, but the number of headsets I’ve pressed, removed (have that tool too) and pressed again, ... so nice compared to the hammer method after enough repetitions.

The frame dies are probably only worth it if you’re building from raw tube more than once or twice. Obviously the head tube reamer paid it’s dues again on this build. Wouldn’t have done it had I not had the tool. Not sure the LBS would have been willing.

 

[SkyknightJohn]

Also, received my seat post today. 5/8” pin with 7/8” top for the seat.

Pretty long insertion (“long is the theme of my parts today!”)

5/8” thick wall tube, should be plenty strong. Of course, one person’s 5/8” is another person’s 21/32”, so I have a bit of fit-up to fix. No worries though.

 

[Chad T]

I used the middle tool, a Cyclus Head Tube reamer/facer (dies for both standard 1” & 1-1/8” headsets). Right tool is a seat tube reamer for 27.2mm pins, also Cyclus. Left is the Park Tools headset/BB cup press. Funny, it’s the only one without blue.

...tool .... alert!

Interesting progression how you ended up here. Those tools are the business.

 

[LukeTheJoker]

My bike fanaticism path went like: e-bikes > they don’t make a good ebike frame > I can do better > need to learn to weld > need special tools > collect underpants > ... “ ___ “ ... > profit!
> hmmm... no profit? > old bikes are cool > RRB forum > Build offs are fun!

 

[SkyknightJohn]

A little fit up today. I ground a smidgeon off the seat pin so it fit and then tried some handlebar/stem combos to figure out where to cut the steerer tube.

1. Chrome stem & flat bar with about 1” of spacers. Too low for me.

2. Chrome stem & flat bar raised. Feels good. I’ll need about 4” of spacers to make that work.

3. Chrome stem & wing bar raised. Will hit my knees in turns.

4. Chrome stem & wingbar low/tilted. Not comfortable on the hands.

5. Black stem (long & riser) low & wingbar. Feels good.

6. Black stem high & flat bar. A bit of a stretch.

#2 & #5 are the best feeling fit, for now. 4” of spacer is a lot. Might look into using a single piece of tube. Or go with #5.

 

[SpikeFC]

#2 & #5 are the best feeling fit, for now. 4” of spacer is a lot. Might look into using a single piece of tube. Or go with #5.

#5 looks cool