Boom sheave

[PabloPicasso]

How do you replace the captive sheave inside an aluminium boom?

I can see the end of the spindle going sideways through the boom end. How is it held in?
The visible end is just flat, so presumably not threaded. Is it an interference fit? How do you remove it to replace the sheave?

 

[Poecheng]

I had this problem and the riggers did it.
Think you would heat the boom and then press it out.

 

[mrangry]

I did this on a z spars boom and it drifted out. I think it only goes one direction which should be obvious on close inspection.

 

[Chiara’s slave]

Hopefully you’ve solved this problem. Mine pressed out by hand, a bit of help with the flat of a screwdriver blade as the lines were still reeved. I now have 4 cream crackered sheaves, 35mm dia, 11mm thickness, 8mm pin. I don’t mind at all shelling out for roller bearing ones instead of the plain bearing nylon things I’ve got. But they carry the reefing lines, it’d be nice to have them run easily but the loading is important! Has anyone seen these for sale? I’ve been looking for a couple of weeks now.

 

[Boathook]

Hopefully you’ve solved this problem. Mine pressed out by hand, a bit of help with the flat of a screwdriver blade as the lines were still reeved. I now have 4 cream crackered sheaves, 35mm dia, 11mm thickness, 8mm pin. I don’t mind at all shelling out for roller bearing ones instead of the plain bearing nylon things I’ve got. But they carry the reefing lines, it’d be nice to have them run easily but the loading is important! Has anyone seen these for sale? I’ve been looking for a couple of weeks now.

Can you buy the sheaves (35mm dia by 11mm thick) and then a roller bearing for a 8mm shaft and get the sheaves machined out for the bearing ?

 

[Chiara’s slave]

Can you buy the sheaves (35mm dia by 11mm thick) and then a roller bearing for a 8mm shaft and get the sheaves machined out for the bearing ?

I can't buy any sheaves of that size so far.

 

[Daydream believer]

I can't buy any sheaves of that size so far.

Surely you can get 12mm ones & get .5mm skimmed off each side

 

[rogerthebodger]

Most Engineering workshop could machine one the size your require from a suitable material

I have had several made to my spec as I make my own blocks

 

[Chiara’s slave]

Surely you can get 12mm ones & get .5mm skimmed off each side

Most Engineering workshop could machine one the size your require from a suitable material

I have had several made to my spec as I make my own blocks

One of these ways is what I’ll do if I can’t get any off the shelf. I have now found a Selden ball race sheave, but I have no spec, and they’re £38. I need a minimum of 6!

 

[Pye_End]

Hopefully you’ve solved this problem. Mine pressed out by hand, a bit of help with the flat of a screwdriver blade as the lines were still reeved. I now have 4 cream crackered sheaves, 35mm dia, 11mm thickness, 8mm pin. I don’t mind at all shelling out for roller bearing ones instead of the plain bearing nylon things I’ve got. But they carry the reefing lines, it’d be nice to have them run easily but the loading is important! Has anyone seen these for sale? I’ve been looking for a couple of weeks now.

Are roller bearings suitable for this application?

 

[dgadee]

I used a press to remove mine but the owner (an elderly fitter) said a good vice can produce 10 ton of pressure.

I am looking for bearings, too. Hard to find correct sizes.

 

[rogerthebodger]

I used a press to remove mine but the owner (an elderly fitter) said a good vice can produce 10 ton of pressure.

I am looking for bearings, too. Hard to find correct sizes.

I fitted deep grove ball bearings into some of my sheaves using a hydraulic press, but a good vice could also be used.

I don't think needle roller bearings or any roller bearings are any good as roller bearings do no locate the pully sideways.

I have deep grove ball bearings in both my top and bottom mast pullies

 

[Chiara’s slave]

Are roller bearings suitable for this application?

Possibly. Clearly it’s a lot of load. Which is why I don’t want to pay £38 without being 100% sure they are up to the job.