propshaft bearings

[George Malcolm GriffettParticipant @georgemalcolmgriffett72482]

[George Malcolm GriffettParticipant @georgemalcolmgriffett72482]

Continuing the rebuild of my vintage model I have now discovered that the propshaft bearings are to worn to be used. The coupling end has a small roller bearing and the prop end is bronze or similar, the problem is how to replace them or remove the tube altogether which is 20″ long with a 3/16″ shaft. In such an old model well made in wood with such a long tube well glued and fitted, it may cause to much damage to attempt removal. Any ideas?

[ashley needhamParticipant @ashleyneedham69188]

Geoff, Difficult. Heat may loosen the bearings in the tube sufficiently to pull them out, could try a self-tapper screw in the bearings and pliers? or drill the bearings out, or grind them out using a dremmel or similar? if the tube was cut off either end could a smaller tube be inserted in the shell of the existing?   Ashley

[Bob Abell 2Participant @bobabell2]

I would try using a 3/16″ rod and longer than the prop tube……..turned down at one end to about 1/16″……so that you have a good shoulder.

 

Slide the shaft up the tube and catch the bearing with the shoulder….and tap it out!

 

Bob………………..Eng (retired)

[George Malcolm GriffettParticipant @georgemalcolmgriffett72482]

My thanks to both Ashley and Bob for your suggestions and success!  I removed both bearings with Bobs idea, which if anyone else has a similar problem works very well. I used the old prop shaft and turned down the end on my lathe which was then just long enough to work. All I have to do now is find where I can get replacement bearings?

Cheers Malcolm.

 

[Ian GardnerParticipant @iangardner62867]

Hi,

If you have a lathe why not turn them on that? You could get a length of phosphor bronze from a supplier.

I found that using a D bit makes a nice close fit rather than drilling the whole diameter. Making a D bit is described in ‘Using the Small Lathe’ by LC Mason which was an MAP publication. You require a piece of silver steel  the same diameter as the shaft . While your’e at it you could make a new shaft as well.

Just a few suggestions. Have fun.

Ian Gardner

[Phil AbbottParticipant @philabbott79958]

Rather than a “D” bit I would ream the hole, nice fit then, as Ian has said turning up a couple of bearings would be the way to go, at least you know they will fit the tube.

Phil

[Bob Abell 2Participant @bobabell2]

Hello George

 

If you are goung to remake the prop shafts…………..I recomend you change to 5mm……………Imperial sizes are very expensive these days

 

Just a thought………………..Bob

[George Malcolm GriffettParticipant @georgemalcolmgriffett72482]

Thanks to you all for your help and advise, I  shall have a go at machining one myself for the prop end in bronze but the coupling end has to be a roller bearing because of the end fitting on the shaft.

Bob you may have a point as I tried to find a supplier this afternoon for this roller bearing, having quoted the number,  it appears to be a now very rare size but did find one in germany for £14-50 plus postage & tax, so your suggestion to alter to metric and go to 5mm may be the best option.

I also like the idea of having a go at making the new shaft myself and will give it a try.

When I have put these ideas into practise I will post and give results

 

Malcolm.

[Bob Abell 2Participant @bobabell2]

Hello George

 

Still don`t think you need a roller bearing at all………Make a brass one the same size as the roller and simply fit that!

 

Bob

[George Malcolm GriffettParticipant @georgemalcolmgriffett72482]

I must admit you got a good  point there Bob   Hmmmmmm…………….

 

see if I can find a piece of bronze big enough!

 

Malcolm.

[ashley needhamParticipant @ashleyneedham69188]

I would like to say Bob has shown his colours as a TRUE engineer. Hit it with a hammer. Oh yes

How about nylon or something for the bottom bearing? This end runs in water, and would thus be self lubricating. Stainless shaft of course.

 

Sometime ago i put a Honda front hub on my Francis-Barnett motorcycle to provide me with some decent brakes, and needed a couple of bronze bushes to bush the brake stay. I went to a local(ish) bearing place and asked about same, 1/2″ bore 3/4″ length and he said yes we can get those..how many 200,,,300… i said er, no 4 would be a good number. he didnt blink an eye and within a week had the required amount. Always worth enquiring at a bearing factor, they may have JUST what you are looking for!!  (or something very close)

 

Ashley

[George Malcolm GriffettParticipant @georgemalcolmgriffett72482]

Thanks Ashley but as I mentioned earlier I did try quite a number of bearing supply people with no luck with one exception that tract one down in germany.The problem I understand is that there is no call for this particular small size anymore, it is afterall over 50years old and even had stamped on it   Made in Great Britian  can you belive it !

 

Malcolm.

[Eric Moffat 1Participant @ericmoffat1]

I agree with Bob, roller bearings and water, particularly salt water don’t mix well. Go with brass or bronze.

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