RB-250 Tonearm Thread

[PR Audio]

Have always found fellow AK members to be very knowledgeable and always willing to help. I am having problems with fitting a Mitchel Technoweight to my RB-250 arm, there is a problem with the Mitchel thread, not properly done, have heard of others having the same problem. Anyways, I am taking the Mitchel to the machine shop that does all the work for my race car to have them rectify the thread, but before they do that, can anyone tell me what is the counterweight thread size of the RB-250?

 

[PR Audio]

anyone?

 

[ripblade]

^ Your machinist should be able to measure the thread pitch from the old stub, no?

 

[vinylengine]

I had the same problem with mine, but a quick clean up with a thread file sorted it. Your machinist shouldn't have a problem cleaning up the thread?

 

[PR Audio]

^ Your machinist should be able to measure the thread pitch from the old stub, no?

Kind of obvious...Thx

 

[PR Audio]

I had the same problem with mine, but a quick clean up with a thread file sorted it. Your machinist shouldn't have a problem cleaning up the thread?

Tried that, will take it to the machine shop so they can run it thru the proper thread die.

 

[ripblade]

Sorry I couldn't be more help. I have an RB 300 stub in my hand now but no way to measure it.

I can't believe Mitchel cut the thread wrong, but apparently their tooling needs cleanup. Usually the problem is at the top of the 1st turn, where it meets the chamfer.

Just guessing though. I fitted my 250 with the Riggle CCM end stub and CW. It fit without issue.

 

[EasyRiderNYC]

Did you really have to wrestle to get the old stub out?

Can you get it started than it seems forced?

Are you going to rewire the arm while you're at it?