Too Big?

[steve garro]

If it's a light press fit, I would install the headset with a bearing retaining compound (loctite 680 or the like) and call it a day. I've done this many times with zero issues. I think it's better than putting the head tube through another heat cycle to flow some brass in there.

Either way, I wouldn't sell it.

For personal use, yes.

- Garro.

[DeeDub76]

I actually did neither. I called CK and got the correct oversized cups.

[Meriwether]

Darrel,
I had this happen and called Park about it a couple of years ago. This mtbr thread goes over the details if you're interested, but basically:

They said the only way to get a precise ream is to use and endmill (on a mill or lathe) so kinda blamed my technique. I was reaming and facing after paint holding the frame by the seat post in a bike stand...so not very secure. They offered to size down my reamer to 43.8mm, and they sent another stock 788 reamer. So i'd do my reams in two steps - the small one first and then follow with the bigger one. Worked like a charm but time consuming. (Someone mentioned it already byt Loctite 680 works like a charm for hand-pressed bearing cups.)

Since then i've picked up Chris King cutters and haven't had the problem over reaming again. To be fair, I also now put a tube block on the downtube and put it in the vise and ream before painting. This is a super rigid setup compared to holding by the seatpost in a bike stand. Lots of cutting oil and a slow steady start and use a rigid fixture. That sounds funny...

Whit

[abbeyQ]

I actually did neither. I called CK and got the correct oversized cups.

This is the best option.

Darrel,
I had this happen and called Park about it a couple of years ago. This mtbr thread goes over the details if you're interested, but basically:

They said the only way to get a precise ream is to use and endmill (on a mill or lathe) so kinda blamed my technique.

Whit

This just isn't true. A reamer will produce a more accurate hole size than an end mill in any setup. If you are hand reaming the setup is pretty moot as the speed of the cutter is so minimal there's not much to go wrong. Reamers cut an accurate hole because they cut on several sides of the hole at the same time. This makes setup less of an issue since the tube isn't deflecting under cutting load. It also means the size of the reamer is critical. You can't compensate for an undersized tool like you can with an end mill. With an end mill you're only cutting at one point on the hole and setup becomes pretty important. The other big thing that comes into play is the starting size of the tube/hole. If you are just trying to ream out weld distortion that's not a great situation. The hole really needs to be undersized so that you can take a complete cut inside the head tube. The Paragon head tubes are designed like this and work well.

[Andrew R Stewart]

Not sure if this comment is applicable to this thread but I've found that the more material I ask a reamer to remove the greater the chance to cut to a size not intended. Andy.

[steve garro]

Just a side note that much of the pain of reaming from fillet brazing is eschewed if you do a proper pre and post heat cycle.

And, ream, chase & face the entire bike before paint!

- Garro.

[Rody]

Good golly this thread has been painful to read.

Want professional level results?

Turn the headtube ID to a couple thousands under in the lathe.

Control your heat when joining.

Efficiently clean up the ID prior to paint with the reamer.

There simply is no one tool, no one single step or process, that can match doing it right.

r

[progetto]

I guess the OP original question was, Is it him or is the reamer over size? Yes, correct process will give accurate consistent results.

Good golly this thread has been painful to read.

Want professional level results?

Turn the headtube ID to a couple thousands under in the lathe.

Control your heat when joining.

Efficiently clean up the ID prior to paint with the reamer.

There simply is no one tool, no one single step or process, that can match doing it right.

r

[steve garro]

I guess the OP original question was, Is it him or is the reamer over size? .

Yep.

And people told him to measure it.

The only reason the thread went beyond that is so everyone could have a pet theory, or to seek affirmation.

Just like every F'Building thread.

- Garro.

[michäel2]

i just my new cyclus reamer and ended up with a king head set that i can just push in by hand, i use a true temper head tube, had the frame firmly mounted i used cutting oil and toke it easy, using verniers to measure the head tube i get a bore reading of 44.10-isch. i used the same verniers to measure the cutter and they seem to be spot on 44.00. both king and canecreek stipulate a bore diameter of 33.95-44.00 max.
im contemplating to have my cutter resized and want to ask if any one here has done this and to what size ?i dare say park tool wont touch o.p. cutters and i am a bitt hesitant to send it to a local tool sharpening mob.