# How To Hold An Atlas 618 Pulley For Machining?



## Curtis (Mar 27, 2015)

Hello guys;

     I am rebuilding/restoring one of these old machines that was given to me by a friend and I ran into a problem that has me scratching my head as to a solution. Specifically, the bronze bushings inside the headstock cone pulley need to be replaced, and I am wondering how, after I have turned and installed new bushings into the cone pulley- how to hold it on the lathe spindle without damaging the pulley so as to finish machine the I.D. of the bushings to a running fit on the lathe's spindle? I am concerned about damage to the pulley because it is a Zamac casting and I am afraid that the chuck jaws will break or crush the pulley.
     For machine tools I have a 9 X 20 Chinese lathe and a Taig mill to work with. I do not see the Taig as being much help here. I am considering using a chucking reamer to finish the I.D. of the pulley bushings (because the I.D. will be reduced slightly after pressing them into the pulley bore), but again- how to hold the pulley without damage to it? Any suggestions will be greatly appreciated.


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## cdhknives (Mar 27, 2015)

Hand reamer and light cuts?


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## Curtis (Mar 27, 2015)

cdhknives said:


> Hand reamer and light cuts?



Well thanks for the reply, but I was not asking how to *cut* the bushing, I was asking how to *hold  the pulley* without breaking it- it is made of zamac.


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## cdhknives (Mar 27, 2015)

You appear (but really you need to clarify the operation you are trying to perform) to be asking how to ream the bushing to final diameter with a reamer after the bushing is pressed into the pulley.  With a hand reamer you would take very light cuts and could hold the pulley in your off hand.  Not everything has to be done on a machine.  You could also lightly clamp the pulley (center, not the lips) to a convenient piece of plywood with a hole to allow the reamer to pass through.

If you are really determined to do this on a machine, you might need to turn a 2 piece ring to slightly over fill the largest pulley groove and (carefully) clamp to that.


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## Curtis (Mar 27, 2015)

cdhknives said:


> You appear (but really you need to clarify the operation you are trying to perform) to be asking how to ream the bushing to final diameter with a reamer after the bushing is pressed into the pulley.  With a hand reamer you would take very light cuts and could hold the pulley in your off hand.  Not everything has to be done on a machine.  You could also lightly clamp the pulley (center, not the lips) to a convenient piece of plywood with a hole to allow the reamer to pass through.
> 
> If you are really determined to do this on a machine, you might need to turn a 2 piece ring to slightly over fill the largest pulley groove and (carefully) clamp to that.



   Cdhknives; Okay, thanks for the reply.  I will have to consider the hand reamer idea.  Filling the pulley groove is a good idea as well. 
                  - Curtis


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## kd4gij (Mar 27, 2015)

While I usley prefer to make most things. Atlas used standerd over the counter oil lite bushings that you can buy at most hardwear stores much cheaper than you can buy the meterial ti make them.


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## Ulma Doctor (Mar 28, 2015)

i would be inclined to finish the bushings by hand on the bench.
you could devise a type of spider for the pulley that could rest in the chuck, or do something stupid like i did here-






the set up above worked like a charm,
but i wouldn't recommend doing what i do 90% of the time ...


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## Curtis (Mar 28, 2015)

Ulma Doctor said:


> the set up above worked like a charm,
> but i wouldn't recommend doing what i do 90% of the time ...



Hi Ulma;
     Lol, if it works and it is safe, then it is ok! I would have held the pulley in a chuck just as you are doing if the pulley was made of steel, but it is Zamac, and as such I feel it would either crack or chip so I can't go that route. 
    I am wondering what kind of chuck that is that you are using to hold the reamer in the tail stock? I am not a "real" machinist- just a muttering, puttering basement shop dweller who pretends to know what he is doing, so there are tools that I do not recognize. And by the way, after looking at that arrangement for a while, I am also wondering if that reamer is free to follow the bore of the pulley using that tool?


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## Ulma Doctor (Mar 28, 2015)

The tailstock Chuck is a double grip drill chuck MT2 shank , it can hold 5/8" to 1/8" tooling.
In the arrangement i had in the picture was rigid, the bore cut in line with the centered tailstock.
A word of caution, if your TS is out of alignment you may ream a taper into your work


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## Curtis (Mar 28, 2015)

Ulma Doctor said:


> The tailstock Chuck is a double grip drill chuck MT2 shank , it can hold 5/8" to 1/8" tooling.
> In the arrangement i had in the picture was rigid, the bore cut in line with the centered tailstock.
> A word of caution, if your TS is out of alignment you may ream a taper into your work



Thanks "Doctor"; I never heard of a double-grip drill chuck, I will have to Google it.  On the rigidity of the setup in the picture; I did not think that the reamer was free floating, so that is why I asked.


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## mattthemuppet2 (Mar 29, 2015)

what about an old piece of 3L belt wrapped around one of the pulleys? it would take some work to indicate it true, but should work for light cuts


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## Curtis (Mar 29, 2015)

mattthemuppet said:


> what about an old piece of 3L belt wrapped around one of the pulleys? it would take some work to indicate it true, but should work for light cuts



That is an interesting idea. hmmm... Thanks for the input!


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## mattthemuppet2 (Mar 30, 2015)

you're welcome! I'll be interested to see what you come up with


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## Strtspdlx (Mar 30, 2015)

You could use the belt or if you have a wood router make a two piece insert to lay in the grooves. May be easier to indicate and steady as you work with it. 


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