Got an old steel frame that I’d like to use. Problem is it’s 116mm spacing and I’d like to use a modern wheelset.
The frame is in great condition so it’s not likely to fracture.
The other issue is the lack of a mech hanger, as it has the old semi horizontal dropouts.
Though I could run it singlespeed.

SS, 120mm track hub?

I was thinking of cold setting it even if I went singlespeed and using a budget 700c wheelset with singlespeed converter on the freehub.

It’ll go I’d have thought. Stud bar and tighten two nuts from inside the frame to push it out. You’ll have to over do it to account for it springing back.

20mm is asking a lot, it’ll be okay for a while but…

It’s only 7mm per side.

Track hub and ss it its only 4mm you will prob just manually squash it in. I used to run my cx with 130 spacing with a 135 mtb hub, and that was an aluminum frame so steel will be better

yup no problem done a few old bikes now
if you have a look on sheldon browns site it shows the proper way to coldset with a bit of wood
me i just stand on one chainstay and pull the other one up a bit then turn the frame over and pull the tother one a bit.
if you want a mech hanger i have probably got one in the shed you can have

20mm is asking a lot, it’ll be okay for a while but…

And what?

and it’ll giver way and crack, at least thats my experience

it will be absolutely fine.

Done two first one broke apart brazing on the seat stay brake bridge..the second I G clamped this bridge and the chain stay bridge(awkward I know) came out well.
Good luck