The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: bakerlonglegs on 02.05. 2016 21:25

Title: How to extract old bearing cups from headstock?
Post by: bakerlonglegs on 02.05. 2016 21:25

Hi,
As part of my '53 A10 project, I'm swapping the old steering ball bearings for new, better, cone bearings (thank you Priory Magnetos for the advice and the parts!   *smile* ).  Now, how do I get the old bearing cups out the headstock?  There is no lip to push against from underneath, see image (don't know why that looks squished, it's not).  However there is a thread on the inside of the cup - is there a BSA tool that fits this?

Title: Re: How to extract old bearing cups from headstock?
Post by: duTch on 02.05. 2016 21:56

 If you don't plan to use them for anything, run a weld stick around the inside and they should fall out

Title: Re: How to extract old bearing cups from headstock?
Post by: beezermacc on 02.05. 2016 22:32

I usually drift them out with a long drift (chisel?!). You can poke something through one end of the headstock until it rests on the edge of the bearing then knock it out. Officially there is an extractor which screws into a thread in the middle of the cup but I'd be surprised if many people use them. You need to be a bit careful with a long drift; gently tap all the way round, not just from one side, or you are in danger of stretching the seat so bearing fit in the future could be a bit loose.

Title: Re: How to extract old bearing cups from headstock?
Post by: morris on 02.05. 2016 22:36

A machinist should be able to turn you a threaded piece of thick wall tube that screws in so you then can knock it out.
However, if you go for the cone bearing conversion, the bearing cups are of bigger inner diameter, so it will be impossible to ever get them out. I drilled 2 small 4 mm holes opposite sides from underneath in the headstock and used a 4 mm drift to knock the cups out. Once they where out, I threaded the holes to M5 and screwed a 5mm grub screw in with some Loctite to close 'em up.
If ever the cups have to come out again, it just needs to remove the grubscrews and screw in 2 M5 bolts to push them out

Title: Re: How to extract old bearing cups from headstock?
Post by: Greybeard on 02.05. 2016 22:49

I also changed mine to the newer cone roller bearings. I removed my old ones by MIG welding a small bar across from one side to the other then drifted them out from the other end of the headstock. The heat of the welding probably helped them to come out. The same thing could be done if I ever need to change the new bearings.

Title: Re: How to extract old bearing cups from headstock?
Post by: muskrat on 03.05. 2016 21:10

I do the same as duTch. A good dob of weld where the balls run. It will shrink enough to fall out.
Cheers

Title: Re: How to extract old bearing cups from headstock?
Post by: bakerlonglegs on 14.05. 2016 21:37

Thanks for the replies all!