Gallery, Projects and General > How do I??

Turning a bearing

(1/3) > >>

vintageandclassicrepairs:
Hi All,
I'm not 100% sure if this is the right place to post this, but if it needs moving please go ahead

As part of a rebuild project on a 1923 Harley Davidson engine that I am currently involved in, the crankshaft drive side main bearing required attention
Originally the factory setup was a bearing race fitted to the alloy crankcase, 1/4in rollers sat in cages in two sets and ran directly on the crank main shaft. In order to set these up properly several sets of rollers are needed in steps of 1/10,000in.  :scratch:
The last person who was at this engine fitted a pair of R16 ball bearings one with a seal that's wider than the other,
When I refitted the flywheel assembly into these and checked to timing side for run out, it was "wobbling" :Doh:

I removed the flywheel assembly again and rechecked my work on aligning it, and all is good !!
I went back and re read the factory book on rebuilding these engines and one section in it goes on about "setting" the alloy cases to get the bearing housings in line
This involves setting bars and a big hammer :bugeye:
I found another publication where the author modified the casing and shaft  to fit a metric  self aligning roller bearing 22205, by boring the casing from 2in. to 52mm and grinding the shaft from 1in. down to 25mm
I decided instead of modifying the case and shaft I would see if it was possible to machine the bearing to imperial outer and inner dimensions

To hold the bearing inner and outer rings absolutely true would be vital to make this a success
I chucked up a piece of 75mm round alloy bar and bored a recess in the end face that was a tight fit on the 52mm outer race, a tapped hole in the centre of the bar held an alloy disc to clamp the bearing against the recess. I have some DCMT tool tips in P25 grade that will machine the  bearing race steel
I then cut away the alloy that was holding the bearing true, I took it really easy cutting the bearing ring, 5 thou off the diameter per cut, making a ball of steel wool in the process !!

To hold the inner race I made another alloy disc, relieving the outer part a little, this was held  by four 6mm bolts threaded in the end of the alloy bar outside the bearing outer
I turned a 10mm length at the end of the 75mm bar down to 25mm a tight push fit for the bearing inner, then clamped the bearing in place
I then drilled and bored the alloy out of the inner race
I did not have a boring bar to take the DCMT P25 tips,  :bang: so I hacked an old boring bar to hold one.
Taking very light cuts and taking lots of measurements as there was only 0.4mm to remove I snuck up to the 1.000in size, It was difficult to see into the bore when the boring bar was in there

I was really happy to achieve the sizes required without scrapping the expensive bearing   :beer: :beer:
The photos hopefully show the progress through the job,
Tomorrow, onto the phosphor bronze timing side plain bearing

John

pycoed:
I love that - great stuff! (But can you imagine the next owner's predicament when he takes this bearing into the bearing shop for replacement & finds they don't exist?)

awemawson:
Sometimes you just have to do what you have to do  :clap:

Nice job  :thumbup:

Joules:
Well done without grinding, that swarf looks evil.  In years to come when it comes back for repair, this will be a Harley Didsumfing  :scratch:

seadog:
I did something similar with a Commando engine I rebuilt. The drive side crankcase was split where a gorilla had driven the main bearing in. I had it welded and re-machined and started to pop it back together. Strange, when I tighten the crankcase bolts the crankshaft stops turning  :Doh:
After a bit of measuring, it transpired that the bore wasn't deep enough, so the outer race was nipping the bearing up. Rather than give it back to the engineer and wait another 4 weeks for him to correct the problem, I went for the quick and easy (dirty) solution. Pop next door to the injection mould manufacturer and borrow their surface grinder   :thumbup:

Sold the engine to a french chap a couple of months later for a hefty profit :ddb:

Navigation

[0] Message Index

[#] Next page