820 countershaft repair

Just a quick check of my van Norman Mill. I’m not sure I have enough vertical travel. I need to mount the boring head and have an 8 inch part and the length of the cutter/reamers does not leave me a lot of vertical travel, if any. I may have to figure out how to do this horizontally with the mill in the horizontal mode


Sent from my iPhone using Tapatalk
 
Doesn't your Van Norman have a universal head? If so you could turn the head 90 degrees mount the casting right to the bed of the mill and shim the casting parallell to the mill spindle . Then bore to size . Use the same set up to fit the shaft to the bushing. Bore the bushing with the same sit up . Then no expensive reamer to buy. It's just a shaft running in a bushing. Should be do able on your mill.
 
Yes it does have a universal head and that’s what I was referring to in my post above when I meant the horizontal position.

I’m quite new to this and have not done much creative blocking and shimming of work on the mill. I primarily of use vices. I was hoping to bore from one side for both holes but again I may not have the Y axis travel for that. Keeping the bore properly aligned (especially on the shaft bore) will be a challenge I have not delt with before.

John


Sent from my iPhone using Tapatalk
 
It might be helpful to clamp the casting to the mill table and indicate off a shaft through the pivot holes rather than trying to align to the
worn surfaces.
 
I was thinking the same thing. I am quite sure I will need to bore from each side. I could align first 1” bore using a 3/4 inch shaft, then turn part around and using a temporary collar at 1 inch with 3/4 center boar, use that to align my second bore. Then do same thing with for the final shaft bore just with smaller bar for alignment. Does this sound realistic?

John


Sent from my iPhone using Tapatalk
 
You should be able to buy replacement bushings from Logan. Or at least find out whether they ever shipped any machines not already bored for the bushings.
 
I have two Logan lathes, a 1948 MW 2136 which does have bushings. And this 1947 820 that did not. If the bushings on the 2136 are any indication they would not be thick enough to compensate for the wear on the pulley side. It is almost 1/8 inch wallowed out at worst point. So I assume I need to make thicker custom bushings.

I also suppose it’s possible it did come with bushings and someone in the past removed them/completely wore away , but the non pulley side is still quite a close fit.

Sent from my iPhone using Tapatalk
 
Well, that would seem to answer the question of whether some machines were shipped with no bushings. If it were mine, I would bore out the good hole for the stock bushing. I would bore out the bad hole and install a steel bushing with Locktite. After the Locktite cured, I would subsequently bore the steel bushing for the bronze Oilite bushing.
 
I hadn’t thought of that approach, thank you. That way future bushings could be stock. Makes sense.

Two questions on tolerance.
How much clearance for the loctite? I have not used loctite before other than for threads. What loctite product do you recommend?

How much interference fit for the factory bushing?

Thanks for all the help everyone.


Sent from my iPhone using Tapatalk
 
I had very much the same problem. I drilled oversize on a drill press (sorry no pictures) doing my best to try to get the bit to follow the original bore not the egged out bit. I still had a slight misalignment mostly because I had to drill each side of the yoke independently from the outside. I corrected the misalignment with a reamer. Yes, this means that each of the bushings are reamed slightly off center, and there is a slightly excessive clearance on either side of where I had to correct the axis. I'm not worried, the Oilite bushings are still better than the shaft running in iron, and even at the tender age of 49, I doubt I'll live to see them worn out again.
 
You must log in or register to reply here.
Back
Top