Unknown crankset retention on a "Schuhof" frame

[Michael_P]

Hello all,

I was directed here from another forum as I have (as they described) a "very old and obscure German frame".
So in restoring the frame I need to get the cranks off and replace the old sprocket as it's bent over at 90 degrees.

However I don't recognisr the way the cranks are retained on the shaft as it's different to every bike I own:

This photo shows the dust cap removed, unlike other bikes the thread on the dust cap is internal rather than external.
And then the crank has a square hole to for a almost square shaft:

So any help on what the "correct" method for getting the cranks of is much appreciated.
I did start to use a gear puller but the sprocket isn't very sturdy and started to bend.

Thank you all,

Michael Powell

 

[Roger Henning]

To me it looks like some one tried to booger a square taper crank on some other kind of non tapered bottom bracket. Think putting Chevy parts in a Ford engine and wondering why it is not working. Roger

 

[Andrew Gorman]

Nope, you have the dreaded German "Glockenlager". They tighten up, but have no internal treads for a puller. There is a tool for pulling them, but I have never seen an actual one. A steel bar is threaded for a typical crank puller bolt and is clamped on to the crankarm in two or three places. The Germans say to remove them, "Get a brave man with a big hammer. If that doesn't work, get a braver man with a bigger hammer!" Here is an entertaining youtube video that shows you the basics, and a German page showing a home made tool. Google translate will get you close, but Deepl.com is usually more comprehensible.

Willkommen in der Welt des Radsports - von der DDR bis heute

Willkommen auf dieser Seite. Warum haben wir uns für das Radfahren entschieden? Woran glauben wir? Hier heißen wir dich willkommen und erklären unsere Mission

ddr-fahrradwiki.de

 

[juvela]

-----

Chainset manufacturer likely Thun.


-----

 

[Michael_P]

Evening, nothing more fun than an old dreaded German engineering. They know how to make things last!

Right, looks like a cold punch is the way to go then. Might heat the crank up to, loosen it up a smidge before I start the hammering.
I appreciate the time guys!

Michael Powell

 

[Michael_P]

Thank you all for the assistance, I can confirm I have got the cranks off. Took a cold chisel, a lump hammer and some hefty hitting. But it's off. Going to stick a cottered crank on since I have it laying about.

Thank you all for the assistance!