Aerzon

I found these small vertical cracks in the lug of the headtube. I don't know enough about bikes/frames to know if this is a major issue or not. It doesn't appear that they extend up above into the top of the lug. (What looks like dirt along the top ridge of the lug there is a network of paint cracking that doesn't appear to be an extension of the cracks that run vertically up the serial number)

I can't even quite tell if the vertical cracks are limited to the paint, or if they actually extend into the structure of the lug. Just looking for some opinions, I know it's very hard to give any definitive answers based on two pictures. (1987 Panasonic DX1000 is the bike in question)

Thanks

gugie 

It would appear that the junction of the lug and top tube rigth above the serial number was not brazed, paint is partially hiding this. The fact that the crack goes right through the serial number stamping "1" makes one think that this was a stress riser, and a thinning of the material right near the end of the non-existant braze. I'm wondering, however, how structural this is. It's odd since Panasonic was considered a fairly high quality frame shop, if indeed it were built there.

Removal of paint in the area is the only way to see if indeed it is cracked.

Aerzon

That's a good observation, I see what you mean now. Paint removal would definitely give a better answer, and it would be in a small enough area that I could clean it up nicely so it doesn't look too shabby. I wonder if it was just not completely brazen? You often see gaps around lugs where the area was just partially filled if I recall correctly.

gugie 

A wire wheel chucked to a drill would make quick work of the paint in that area if you were thinking of getting the gap filled. If not, and this were the only area of concern, I'd be inclined to ignore it, but would like a second/third opinion from others such as @bulgie, @JohnDThompson, who have brazed more lugs than they could probably count.

JohnDThompson 

Before ruining the paint, I'd pop out the headset cup and look at the inside of the head tube to see if the crack extends into the tube or is just in the lug.

Aerzon

I've had it out recently and can confirm that the tube looks good inside. Nothing but light surface rust and a small mark from the stem expander wedge at some point, no cracks or anything inside.

gugie 

Hmm, stem expander wedge would mark the inside of the fork steerer, not the headtube. Unless the expander wedge was really horked down and dented the steerer so much that it rubs on the inside of the headtube...

Aerzon

That's my mistake, not thinking of the anatomy of the bike properly. I'm thinking of the steerer that comes off of the fork, not the headtube itself. I'd probably have to take the fork out then to get a look at the headtube, since that steerer is it's own tube that rests right inside the headtube?

79pmooney

Yes. You will need to pull the fork out. Then you will have to knock the headset cup out to see the headtube/lug interface and inside of the headtube.

Mad Honk 

From here a thousand miles away, it looks more like a paint crack and not anything structural. Until the crack seems to expand I would just ignore it and think about it as a paint blemish. JMHO, Smiles, MH

gugie 

Correct. The fork steerer pivots on the headset bearings. To look at the head tube you need to remove the fork.

repechage

I would be tempted to remove the headset and face the headtube, the appearance suggests that the lower headtube is not fully in contact with the headset cup.

the overall appearance suggests crack check dye time to me.

and chemical paint removal, wire brush can smudge things a bit.

icemilkcoffee 

What kind of bike is this? Did somebody jam a 30.2mm OD ISO headset cup into a 30.0mm ID JIS headtube?

Bad Lag

Tap it and listen Brazed will have one sound, two unbrazed items will sound differently - tinny, damped, two tones.

gugie 

The question is what do you do about it if it isn't brazed on? It appears that it's just the front edge of the bottom lug. The critical part of the braze is at the junction of the head and down tube. As a mental experiment, what would happen if that little lip part of the lug wasn't there?

As long as the head tube isn't cracked, I'd let it be.

@repechage has good eyes. I looked again and it does appear that the bottom headset cup isn't pressed all the way in.

smd4

Hopefully that's just an odd reflection.

merziac

Maybe the cup didn't want to seat all the way for galling or the seat being to tight, possibly stressing it and cracking the paint or?

smd4

Using a proper headset press, I can't imagine it going in that far crooked.

merziac

You would be surprised and with a proper press you could do more damage if you force it or try too especially if the HT was poorly reamed and faced.

smd4

If it went in that far, a good headset press would have assured it would have gone in straight. In my experience.

merziac

Maybe so, in my experience you never know what hamfisted butchers are capable of, until its too late.

Plenty of them can ruin the workpiece and the tool regardless of how foolproof they may be.

smd4

True.

If it is in crooked, I can see that being easily accomplished with a piece of wood and a hammer by said hamfisted butcher...

Aerzon

It's an 87' Panasonic DX1000. It being an ebay bike, anything is possible. It seems like I find something new everytime I check it over.

Some days I wish I would've gotten a project bike to build up on my own. Then if something is wrong, I know I put it there and how it got there in the first place. The only thing I've done on this bike is change the seat, tires, and install a Cateye Velo.

droppedandlost 

are you talking about The Bike Butcher of Portland?

merziac

Not him, he's the fixer of such things.

I'm talking about all the hacks I have followed, working on cars, bikes and mc's for over 50 years of wrenching.

Bikes since 12 yo, riding and drag racing mc's for 40+, cars professionally for 35+ and more.