Drilling & reaming bearings in situ

[SignalFailure]

• Can someone help offer advice on this basic question please....
  
  I need to mount a 1/4" shaft horizontally through two standards/bearings. If I make the standards together (sweat or glue them) then drill/bore/ream, the resulting holes will be parallel. However, once they're mounted on the baseplate any error in the position of the mounting holes will throw them out.
  
  It seems to me that if I:
  
  Make the standards (simple steel rectangular blocks) together and make holes for the bearings.
  Mount the standards on the baseplate in their final position.
  
  Fit a centre drilled brass 'plug' in each, turn the whole on it's side and mount it on the mill/drill
  Drill and ream straight through both bearings.
  
  ...the result should be good. The question is, will the drill find the centre on the second bearing or is a hole needed on the 'lower' bearing at all as the drill will be guided through the first?
  
  What's the proper way to do this?
  
  (For info my gear is limited ;D, the standards are about 1" high by 3/8" thick mild steel, the brass bearings will sit in holes about 7/16" dia)
  
  TIA
  
  Paul

 

[Twmaster]

Why not use a shaft as the alignment tool? Mark out and make your mounting before getting too involved and have to work around other parts?

 

[SignalFailure]

Mike, do you mean make the 2 standards together, fit bearings, put shaft through then clamp to baseplate and drill holes into standards? I did try this once but although standards and bearings were all lined up, as a whole they were fractionally out of sqaure to the base

 

[Twmaster]

You could possibly make the mounting holes in the base slotted a bit or slightly oversize allowing for adjustment? Using the shaft as an alignment tool just seems the most simple way...

Otherwise it sounds like great care needs to be taken to ensure proper alignment.

 

[vlmarshall]

What about line-boring the standards,bolted in position on the baseplate, on a lathe?

 

[steamer]

What about line-boring the standards,bolted in position on the baseplate, on a lathe?

I agree.

There are two inversions of this. Mount an angle plate on the faceplate and mount the parts on that., or mount the baseplate/standards assembly on the cross-slide and bore them with a between centers boring bar......

Either way would be the method of choice as it dials out ALL the errors you mention.

Dave

 

[SignalFailure]

Thanks fellas, someone did suggest this to me ages ago but I have no means to mount it on my minilathe. I reckon a makeshift boring table would be do-able though.

 

[Kermit]

I think the first suggestion you got was the best one.

put the shaft in the finished standards and place on your base and mark the holes for the standards. You will need to have the mount holes go completely through the standard so you can center punch the base plate through it. then drill the hole in the base plate and THEN go back and tap the holes in the standard and enlarge the hole in the base to clearance size for the screws on the bottom.

I will be doing the same thing described above when I get my crank shaft completed on the Hasbrouck #6. That is the way Ray described the work needed to mount the standards.

Kermit

 

[Deanofid]

How small is your lathe, (or how large is the work piece)?
These were done on a Taig lathe. Not known for being a large machine.

Something holds the compound to the cross slide on the mini lathes.
Use that to mount a jig plate and mount your work piece to the jig plate, then
align bore the needed holes.


Dean