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-   -   Knob puller (https://www.vintage-radio.net/forum/showthread.php?t=166975)

Bobdger 20th May 2020 1:09 pm

Knob puller
 
5 Attachment(s)
I have an old Bush AC41 that the knobs are refusing to come off. Inspired by a post here about a American knob puller for musical instruments I designed and built a small puller.
The outer tube is a offcut section of 63mm clear plastic pipe. The claws I designed around some M8 coach bolts, this meant that I could slide the jaws open to pass over the stuck knob, slide the jaws together and then hand tighten the retaining nut. The jaws would stay at 180 apart.
I had the jaws punched and bent at my local sheet metal shop. They could not punch these until the following day so meanwhile I cut out a 68mm circle from a piece of 10mm thick poly prop sheet with a hole saw. This gave me a centre 6mm hole to place a bolt through so that I could hold it in the lathe chuck. I then machined the disk down to 65mm with a 2mm locating rebate that fitted snugly inside the clear tube. The next day the jaws arrived with me, the 8mm slide was a little tight so I opened this up with a file, now works well. The parts were assembled with a M10 nut as a spacer to allow for the end of the square on the coach bolt. On the puller outer end I fitted a m8 penny washer and a M8 wing-nut.

Bob.

merlinmaxwell 20th May 2020 1:58 pm

Re: Knob puller
 
That's a proper job, you could rent it out!

ex 2 Base 21st May 2020 5:56 pm

Re: Knob puller
 
Hello Bob, I like your idea and will make myself one. Thank you for posting the pictures and the description. Next I need to locate a piece of clear plastic. Ted

stevehertz 21st May 2020 7:00 pm

Re: Knob puller
 
Yep, it was my original post back in 2015. Here's that post plus info re another home brewed one:

https://www.vintage-radio.net/forum/...d.php?t=116962

Excellent job Bob.

stevehertz 5th Jul 2020 7:30 pm

Re: Knob puller
 
Just bear in mind if you're making one of these that on the commercial one I bought the main tube's bottom edge is 'protected' with a rubber strip. If you don't fit some kind of softish protection like this then if the knob is stuck and a lot of pressure has to be applied, then the rim of the tube can dig into the finish of the radio/whatever.


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