BB facing issues - need suggestions

[JuanGrande]

So I am nearly finished building a new cx frame to use for single speed. Went to face the bb and ran into a problem that I need some help with (I have used this bob reamer/facer fives times, it's a cyclus brand, and have not had any issues). Faced the drive side with no problem - turned out great. Started on the non- drive side and immediately got chatter (my term... Almost like it was skipping). Tried increasing tension, relieving tension, backed the facer off completely to check what was going on... Nothing seemed to work. Here is where it is at;
Attachment 47967

Some here are my questions;
1) What caused this?
2) And what can I do to fix the problem? File it flat and start again? I checked the cutter and everything looks normal.

Any suggestions would be greatly appreciated.

Jonathan

[deepsix]

Is that Italian or English?
What kind of bottom bracket are you going to use in the frame?

Get some calipers and get an accurate measurement of the width of that BB shell as it is. Measure in a few spots and find the average.

I prioritize having the correct BB width for modern BB systems as much as having the faces parallel (if the bearings are not the right distance apart, the preload won't be correct). If its wide vs. spec-- get some cutting fluid and use the tool properly with much less tension to smooth that out. Don't take off too much material. If its already narrower than spec, use a thin BB spacer and move on with life.

It looks like you dug in too hard with that tool.

[Dallas Tex]

From the one picture, it looks like someone tried to face that shell using waaaaaaay to much tension/pressure one the cutter. It now has 'waves' of highs and lows. IMHO continued facing will deepen the lows and not correct the problem. Use a hand file and remove the highs, then re-face with minimum tension on your facer. Don't skimp on cutting fluid.

BB facers are designed to remove a tiny bit of material. Use as little tension as possible to accomplish this.

[Eric Estlund]

Indeed. If it's the Cyclus all in one- there is no need to crank that huge spring down. Just enough to hold the tool to the face of the shell. More tension on a hand mill is almost never the right way to go. If this starts in again, pull the tool and assess/ clean/ file, etc.

[steve garro]

Scalloping.
Ease up........
- Garro.

[Tristan]

I use the Cyclus tools and have experienced similar scalloping / chattering. What I've found is that the fit of the guide inside the BB threads makes a huge difference - on frames where the thread diameter is larger the guide is able to move around and rock more which increases the likelihood of this chatter. It would be interesting to measure the ID of both sides of your BB to see if the NDS is larger.

The Park BTS-1 for example locates the facing tool off the actual threads and seems to be a much more secure and rigid:
bbtap_8.jpg

As others have said using minimal spring tension for the first few turns (especially when removing the paint) and going nuts with cutting fluid (fluid = cheap, tool = expensive) seems to work 99% of the time for me.

[steve garro]

The Park BTS-1 for example locates the facing tool off the actual threads and seems to be a much more secure and rigid:
bbtap_8.jpg

As others have said using minimal spring tension for the first few turns (especially when removing the paint) and going nuts with cutting fluid (fluid = cheap, tool = expensive) seems to work 99% of the time for me.

I have that same tool & it works just as you have described - pretty good tool.
- Garro.

[JuanGrande]

Thanks guys for the responses. Definitely think I went in with too much pressure... but I am curious about the play issue. Something just felt "off" from the start. Will try and hit it with a flat file to knock down the high spots and retry. Thanks.

JC

[e-RICHIE]

So I am nearly finished building a new cx frame <cut>

Any suggestions would be greatly appreciated.

Jonathan

I have mentioned other times that I only face a shell once (if at all), and do it before the frame is made. When the industry went away from cup and cone and bearings for the bottom bracket, I saw no real need to use the tool just to use it. This is especially so when the meat and potatoes of the assembly are internal and little if anything at all is affected by the faces. The parts from the casting houses are so precise in their as-delivered state (and have been for decades atmo...) that any hand tool operation couldn't possibly add a better surface to the ones they create during the machining. Full disclosure: I haven't used a facing tool for well over a decade, and it may be much longer.

[steve garro]

Thanks guys for the responses. Definitely think I went in with too much pressure... but I am curious about the play issue. Something just felt "off" from the start. Will try and hit it with a flat file to knock down the high spots and retry. Thanks.

JC

Well....................are you brazing round shells into ovals?
I'd suspect so.
After full brazing of a frame on a Paragon shell I can just spin the tools in with very minimal pressure (the chasers)
sometimes fingers only.
How many frames have you brazed, and are we talking lugged or lugless.
- Garro.

[progetto]

Well....................are you brazing round shells into ovals?
I'd suspect so.
After full brazing of a frame on a Paragon shell I can just spin the tools in with very minimal pressure (the chasers)
sometimes fingers only.

- Garro.

Steve, You don't use heat sinks when brazing, just fast pace and proper sequencing? Tis a skill that comes with experience.
Bill

[steve garro]

Steve, You don't use heat sinks when brazing, just fast pace and proper sequencing? Tis a skill that comes with experience.
Bill

Nope.
I *do* preheat the entire shell evenly, however, so it does not shrink and contract unevenly - this is the true key.
- Garro.

[JuanGrande]

This frame was lugged (previous was lugless). Definitely didn't over-cook this one - though I know that could be an issue. This is frame #9. As I mentioned, the drive side went in nice and smooth, and the non-drive seemed to be catching right away... which led me to increase the spring tension. Then as I thought about it, I backed off the tension, but the waves (chatter marks) were already done. I wondered if it was do to the threading portion of the tool not being fully interested into the shell (it was 95% in with just a couple of threads showing when I started to face). I had my new shop assistant with me supervising (my 2 1/2 old daughter who likes to watch daddy work) which also led to me being distracted at times. Just a couple of life lessons learned/reaffirmed - always start small, and keep the distractions to a minimum (its tough because I want my daughter to come out into the workshop with me, so I will have to work on this).

JC

Well....................are you brazing round shells into ovals?
I'd suspect so.
After full brazing of a frame on a Paragon shell I can just spin the tools in with very minimal pressure (the chasers)
sometimes fingers only.
How many frames have you brazed, and are we talking lugged or lugless.
- Garro.

[steve garro]

I wondered if it was do to the threading portion of the tool not being fully interested into the shell (it was 95% in with just a couple of threads showing when I started to face).
JC

Is this possible?
You mean the opposite side?
- Garro.

[JuanGrande]

With this tool, yes. So on the drive side, the threads fully inserted, but on the non-drive side, they didn't fully insert. When I backed out the drive side a turn a turn or two, I was then able to get the non-drive threads to fully insert.

[steve garro]

With this tool, yes. So on the drive side, the threads fully inserted, but on the non-drive side, they didn't fully insert. When I backed out the drive side a turn a turn or two, I was then able to get the non-drive threads to fully insert.

Were you bottoming out on the ends of the chainstays that you can see in your picture?
- Garro.

[suicideking]

Hitting the CS, or the BB is less than a 68 measured in its current state.

[Doug Fattic]

Just to add to what others have said, a sharp tool under too much pressure will cause the waviness. The extra spring pressure makes the cutter start to dig deep and then it can't continue to hold such a big cut and it retracts some as continues in the rotation. My solution for this problem was to use another cutter with a different amount of teeth which would level the face again. Just today one of my customers dropped by with a concern that the face of his bb shell was wavy after just having it faced at another shop. A few minutes with my facer under just enough spring pressure and all was right again.

[JuanGrande]

So I got some time this afternoon in the shop with my little helper and fixed the problem. I knocked down the chatter/waves with a large file and then came back and refaced it with a much lighter spring tension. Worked like a charm. I also made sure that the threads for the chaser where fully into the shell, and used even more oil than usual. Thanks everyone for the advice. Looking back, I think it was a combo of not having the reamer threads fully into the shell and using way too much pressure.

JC

[Tristan]

My solution for this problem was to use another cutter with a different amount of teeth which would level the face again.

Simple and brilliant - that's why you're paid the bigbucks Doug.