How do I fit this bushing?

[JW714]

Hi all, I have a '77 Harley transmission that I need to replace the 4th gear bushing.I have the bushing installed in the gear, now I need to size it to the mainshaft. I have a 9" South Bend lathe but I don't know the correct procedure for boring the bushing to size.What measuring tools are needed? I have a set of inside spring calipers but not much else for inside measuring.The clearance that I am shooting for is .0007-.0012..Thanks,John W

 

[irishwoodsman]

i would use a small boring bar but it really is going to have to be centered perfect, as far as what you need to take off you could use your dials on your lathe if they are right on or you could mount a indicator on your cross slide and use it to determine how much your takeing off, i think what i would do is when you chuck the gear instead of centering the gear put your indicator on your bearing to get it indicated exact:thinking:

 

[pjf134]

It seems to be a press fit, so I would polish up the shaft first, then take a measurement of each and see what you need to take off the bushing to get it to spec., maybe boring or reaming needs to be done if out enough, it's hard to say without knowing the dia. required for final spec. A polish might work too if close enough.
Paul

 

[JW714]

I was going to indicate off of the bearing surface on the outside.My problem is measuring it.Are my spring calipers good enough?Thanks..JW

 

[JW714]

It seems to be a press fit, so I would polish up the shaft first, then take a measurement of each and see what you need to take off the bushing to get it to spec., maybe boring or reaming needs to be done if out enough, it's hard to say without knowing the dia. required for final spec. A polish might work too if close enough.
Paul

The bushing press fits in the gear. The clearance is .007-.0012 between shaft and bushing.Shaft is 1" I have a new shaft for this. Thanks...JW

 

[Highpower]

Inside and outside micrometers highly recommended.
2nd choice: outside micrometer and a telescoping gauge.

You only want to have to do this ONCE. Make the best of it and beg, borrow or st..... errr, buy the proper tools IMHO.
-or- Perhaps take the parts to a local automotive machine shop and have them size the bushing for you.

 

[JW714]

Would a dial bore guage be a good tool? Theres one on E-Bay #170750476334 .

 

[British Steel]

Might be easiest to make a temporary go/no-go gauge?

You know the maximum and minimum bore sizes (the 1" shaft plus 12 tenths and plus 7 tenths), so turn and polish a piece of scrapbinium to 1.0012" at one end, 1.0007" at the other, use to check the bore as you go along - if the 1.0007" end goes in but the other doesn't, you're where you want to be! This has the advantage that you don't need to measure the inner of the bushing to tenths, with a 0-1" tenths external mic' you'll probably be able to measure to a few thou" over, and you'll be able to verify the shaft diameter really *is* 1.0000"

To be more cautious, you can turn a few smaller (by a couple or three thou" a time up to 0.997", then a thou" to 1.000") steps on the 1.0007 end, to give an idea how close you are on the bore, and *be sure to break the sharp edges* (however smooth it feels after turning) with a very smooth file, fine abrasive paper or a stone so you don't raise burrs on the edge of the bushing.

Just my ha'pennorth,
Dave H.

EDIT: I meant smaller, so the measurements should have been smaller!

 

[JW714]

Hey Dave this sounds like a great way to do this . Thanks I'm going to do it . I'll report back on my success...JW

 

[gary.h]

Hey Dave this sounds like a great way to do this . Thanks I'm going to do it . I'll report back on my success...JW

looking forward to the results one thing about them harley 4 speeds if its to much tolerance you can still run em! they make all sorts of strange noises when wore out but they,ll still get ya down the road...