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Another Paddleducks build log

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kvom:
I'm curious to know how the bearings are working out.  Is the crank pretty "free spinning", or is there still a bit of friction?

spuddevans:

--- Quote from: kvom on August 29, 2009, 04:36:14 PM ---I'm curious to know how the bearings are working out.  Is the crank pretty "free spinning", or is there still a bit of friction?

--- End quote ---
They are pretty free at the moment, and I have done absolutely nothing to the bearing blocks apart from boring the holes. No lapping or anything. I have a bit of friction with one bearing block when it is clamped down tight. I cant lap the bearing blocks as when boring out for the ball races the bore's do not go all the way through  ( if you know what I mean ). I might get all the bearing blocks clamped together with ball races installed and a 5mm rod through them, and then gently polish the bottom with some wet-n-dry on my granite surface plate to see if that will reduce that friction.

Having said that, it is only when that particular block is tightened up well that the friction appears, so I reckon that whatever differences that exists between the blocks can only be very slight. With that block's mounting screws just slightly loosened up the crank is quite free spinning. I have some edges of the bottom plate that need filing to give a better clearance for the crank-webs, and without the eccentrics having a grub screw to fix them, they tend to rub and cause a bit of friction too.


Tim


EDIT

Since this post I have bored the bearing blocks completely thru @8mm, and then Lapped them as per the plans, but using a length of 8mm ground stock and some T-Cut. This has made the whole bearing/crankshaft assembly exceedingly free and smooth, even with the bearing blocks completely tightened down.

If I was to do it again I would just bore the bearing blocks all the way thru at the required diameter for the ball races, if needed you can always make up a little packing bush to seperate the 2 ball races in each block.


Tim

arnoldb:
Tim, you're doing well  :clap: and  :bow:

I'm scared - very, very scared... - I think you are infecting me with  :proj:    :doh: :doh:  :bang: :bang: :bang:

 :beer: , Arnold

spuddevans:
Thanks Arnold  :thumbup:

--- Quote from: arnoldb on August 29, 2009, 05:20:16 PM ---I'm scared - very, very scared... - I think you are infecting me with  :proj: 

--- End quote ---


Dont be scared,  :proj: is nothing to be afraid of, just keep a healthy stock of barstock and keep making chips  :dremel:  :lol:

Tim

bogstandard:
Tim,

For the low block, just shim it up with layers of bacofoil, it might only need one or two. But get it before you have done the Sunday roast in it, less crinkles.

If you start to try bringing the others down to match the low one, you just might make it even worse.

John

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