I’ve built two frames and both of them with striaght headtubes one is 1" and the other 1 1/8" so 30 and 34mm ID and the OD is 31.8mm and 36mm.
I’ve not used any lugs and am a little concerned about the wall thickness.
What’s the thinnest wall you would be confident with in a headtube?
Neither of them are painted so I can still solder a reinforment ring on to them, but I don’t want to do it if it’s not a safety issue.
What kind of bikes are they? I don’t like to go under 1.1 or 1.2 wall without doing a ring.
-Walt
In short they are gravel bikes. The 1 1/8" will see quite a bit of luggage and the 1" probably some xc/singletracks.
So by your standard I guess a reinforcement ring is probably a good idea 
Reinforcing would be a good idea.
I have the same concern, and see I should most likely to the same. Where to you guys find reinforcement rings?
I used too thin a headtube on my first frame (looks like 0.9 or 1mm) and the lower thinned out too much when reaming. Got some tube to make reinforcement rings for my second frame, 1.5” x 0.035. I got the head tubes from Henry James years ago and didn’t know what I was ordering. I’m guessing these are meant to be used with lugs?
I think reinforcement rings are getting harder and harder to find, especially for 36mm (1 1/8 headtubes). I think it would be cool to see the straight steerers pick up again.
I don’ think Nova makes them anymore: https://cycle-frames.com/products/201980-3600-nova-oversize-head-tube-reinforcing-ring-for-nova-oversize-head-tube-46-4mm?_pos=1&_sid=4bf44f543&_ss=r
Solid bikes used to have a cool 44mm headtube reinforcement ring.
Metal guru also appears OOS Metal Guru IS47 Lower cup, 46mm ID – Metal-Guru.com
First post and just gathering tools and tubes for my first frame. The forum came along at the perfect time for me, so much good info here. I was wondering the other night if my head tube that I ordered is to thin. I ordered a 46.4mm x 660 long tube from Nova. From the conversation above it sounds like I will be ok for a short travel 29er hardtail mountain bike.
Waltworks waltzing in here with the definitive answer. Chapeau!
I personally add reinforcing rings to all headtubes for a few reasons;
A little while ago I put together some details of what I do for headtube rings and that write up can be found here. This was before the design was finalized so take the actual ring profiles with a grain of salt. Since then I still machine all of my headtube rings so I can control the fit and finish of them. I also machine them slightly oversize of my final dimension so I can go back in and machine them to the final dimension after brazing.
I also add in some details like axially filed grooves to help with wetting out the joint and some punch marks to get the fit dialed for fixtureless brazing.
Post-machining of the HT ring also makes the final product look pretty good before powdercoat/paint which always helps your final finish.
Great idea! I also machine rings for all my headtubes and normally have to futz around with something to hold them flat for the first dab of silver.
@Ian at The Lost Workshop makes some of the most beautiful reinforcement rings for both 36 and 46 headtubes!
Thanks for all the inputs!
Because I hadn’t thought about the reinforcements in the first place I welded the DT and TT so close to the end of the HT that it was a bit difficult to put in a reinforcement ring. Had about 3mm clearance from the end of the bead to the end of the tube.
I started by turning a tube to over the HT and filled it to fit around the TT/DT. Then I ate lunch. When I came back I felt that the thin section was a little to thin (1.2mm thick and 2.5mm tall). If I was gonna spend time and energy on reinforcing might as well try and do it right so and went back to the lathe and made a new set with some extra material (2.7mm thick) at the top/bottom of the ring.
This is what it looks like after a little shower. Happy with the outcome and pretty confident that this will be strong enough even with the thin section at the tube joint. Would you agree?
Also made reinforcemnt rings for the 1" HT build but didn’t get any photos of it.
Just orderes tubes for the next couple of frames and got some reinforcement rings with the order 
