I'm planning on building a Tach Drive Distributor from a Core a friend of mine gave me. Its one of the early ones with out the hole on the backside of the Tach Drive. The internal surface looks to be in good shape were the thrust area is. I have read a number of the Threads on the subject. This question is probably for Lars or anybody else who has done this. So what happens if the shaft binds on the new bushings ? Everybody sez it will need to be honed. OK, how to do that ? You must be useing a Mandrel between the two bushings.

 

If you use the insert tool and drive the bushings gently you "should" have no issue. But....there's always the exception.
Drive the lower bushing in with the tool. It should easily seat when the tool bottoms out against the housing.
The top bushing is a different beast.
Drive it in with the tool but tap ever so slowly making SURE you don't drive it too deep.
You need to pay close attention to the height to allow for the breaker plate install.
Drive it too deep and you'll be buying a new bushing set.
So leave it a bit "proud" when you first install it then tap tap tap to get it exact - you can always tap deeper but you can't pull it back up.
I have an old main shaft that I use to install/align the upper bushing as this lets you align the upper bushing with the lower during install and you can see the breaker plate height.
If you get this far and there's no bind on your main shaft (test test test) then you're probably good to go = beer time.

As to your hone question: I had one that was tightly binding on the main shaft.
Yes they make a reamer/hone/tool and a machine shop blah blah blah $$$ could'a fixed it.
BUT: I had a spare bushing set and figured that the worst that could happen was I would need to start over.
So I "honed" the bushings using a drill bit just under size of the bore and taped a wrap of oiled 2000 grit sandpaper chucked in a 1/2 drill.
A bit like honing a block cylinder and repeatedly tested the main shaft for fit until I was satisfied.
This worked amazingly well.

 

I have been under the belief that using abrasives on bronze bearing surfaces is not recommended because the grit can embed in the bronze and then abrade the shaft. Cylinder honing is different because the abrasive won't embed in the cast iron. Have I been misinformed?

 

You're not misinformed - you've just got more money
Sintered/oilite bronze bushings (vs solid) can capture grit so reaming is the preferred method.
Yes they make a reamer/hone/tool and a machine shop blah blah blah $$$ could'a fixed it.
Wasn't willing to spend $$$ on a one use tool for a $20 part.
Rebuilt that distributor +18 years ago (due to tremendous upper busing wear = breaker plate slop)
and had a chance to inspect it a couple years ago, still looks like new.

 

So this is how I did mine. The new Bushings were tight on a new shaft right out of the box. They were snug when pressed in the housing. For the most part the Shaft really didn't want to go in at all at first. I took a piece of round bar and turned it down on my lathe until it was loose to fit. Then I took a Cut of Wheel and scored a line down the shaft 3 inch's or so. Then with a Drill Motor turning the Mandrel the scored line acted as the cutting surface and it slowly opened up the bushings. The bottom of the top bushing where the 1/2 moon is cut out needed the most attention. It took about 30 minutes of Honing a little at a time to open things up. If I was to do this for a living I would get a real Mandrel.