BCA jig borer spindle adjustment

[Andrew Knowles 2Participant @andrewknowles2]

Just wondering if there are any machine tool experts with experience of adjusting the spindle bearings on a BCA jig borer.

The bearings are adjustable bronze bushes but I am not sure how tight to run them

Any advice would be most welcome

Many thanks

Andrew

[Andrew Knowles 2Participant @andrewknowles2]

[William SParticipant @williams]

Hi Andrew

The technique I used on my first BCA was to do it at the dead of night in complete silence and listen to the oil squidding about with me swinging about on it, nipping the bearings until there was minimal noise but not excessive drag. it was a well used machine so that may have contributed to the fact I got that spot on first go as I can recall.

I have since tried that method on my next BCA which is in immaculate condition (scraping marks still on both bronze bushes!) and it works as it should, The manual states the bearings will run warm which mine do with the above method, so I guess it works!

One important thing to mention is to not heavily pack the thrust bearings with grease they don't like it. I did and on top lick the spindle would suddenly stall but immediately restart so I can only assume this was the cause. Since it has now splattered most of that grease around the shed walls/me it seems to have stopped doing that trickery!

Its good practise to get the spindle warm before making any adjustments. I'll try to find the post which links to a copy of the manual which gives very vague lubrication and adjustment details, if you don't already have a copy.

Really it comes down to not running hot and the other extreme of chatter it use. So just experiment and keep an eye on it.

William

[Andrew Knowles 2Participant @andrewknowles2]

Thanks William

I will run it for a while to warm up then check again.

It sounds a lot happier now after my initial adjustments but I will keep an eye on the temperature.

I also made the mistake of greasing the thrust bearings which resulted in one of the ball cages breaking up. Luckily Simply Bearings managed to find me replacements. Now I use only 32 weight hydraulic oil on the BCA and the Myford

Kind regards

Andrew

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