Pulley material ?

[pelallito]

I found this today and thought that I would find an answer for a question that I had. It was headed hard Al vs mild steel-
http://www.homemodelenginemachinist.com/index.php?topic=9651.30
I am still confused!
I recently bought an Atlas horizontal mill, and I very happily took it home. Shortly after replacing the original motor, I started to make a light cut on a piece of steel to cut a hex and my spindle pulley started spitting pieces out of the machine. I started making the pulleys out of pump shaft material that I scrounged up, but it was hard on all my HSS and carbide cutters that I used on it. Plus when I had the largest one started- the motor countershaft pulley- I realized that it would be very heavy compared to zamak.
I decided that the 6061 T6 would work fine after doing some research, and switched to it. After reading the thread, I wondered if I should have tried using something else.
I am making 4 new pulleys for the machine.
Could somebody give me some advice before waste any more time and effort? ???
Thanks for the help.
Fred

 

[Stan]

6061 T6 will still be there long after you are dead. I have bought many used machines and none came with a motor, or if they had a motor they would have the wrong pulley. Many machines use a two step pulley on the motor that is unique to the machine, and frequently unavailable.

If you have round bar of sufficient size for your pulley, use it. If you need a larger size, cut it out of plate. If you need two steps, bolt two pieces of plate together.

 

[steamer]

Considering the original pulley was probably made out of a zink diecast called ZAMAK which Atlas toughted through out their brochures, I think Aluminum is just fine for this application.

ZAMAK "disassembly" of various bits of Atlas products is a recurring song I have heard before.

Dave

 

[pelallito]

Stan and Dave,
Thanks fo the reply. That made me feel a lot better about what I was doing!
I bought round stock in the closest size to the OD that I could to make the 2 and 3 step pulleys.
The original spindle pulley I started on, will be the only steel one.
I am not sure that the Zamak broke because of age or because I did something wrong, because of ignorence. Might have been a little of both.
My machine came with single step pulleys on the motor and the countershaft, instead of the 2 step that is normally there.
Thanks again.
Fred

 

[Tin Falcon]

Modern manufacturing makes pulleys from plastic before that pot metal aka ZAMak and other trade names were used.
Pretty much the same with gears.
You can use just about any machinable material that has reasonable strength properties. to soft or too brittle can cause problems and of course good to excellent machinability.
Tin

 

[pelallito]

Tin,
Thanks for the reply. I guess one of the questions that I had, was whether I should have ordered and used, the stronger aluminum from speedy metal or online metal rather then the 6061 t6 that that I found locally.
Worst comes to worst, this has been a learning experience and I make them again. I have been thinking that I rushed into this project haphazardly! But I really want to use my mill for a bunch of unfinished projects.
I should have taken the dimensions that I was given and changed them to work with a 3L belt all the way around. I might make them again once I have the mill working again. Then again, why fix it if it is working?
Thanks again.
Fred

 

[Maryak]

Then again, why fix it if it is working?
Thanks again.
Fred

In my day it was called Planned Maintenance. :

Best Regards
Bob

 

[pelallito]

In my day it was called Planned Maintenance. Bob,

You are completely right!Thm:


But I will be able to take my time and make them at my leisure if my little mill is making chips on my other projects. I could make one set and install them, then the other set and install them.Right now the pulleys are going to fit a 4L belt size but they will be a little tight.
Best Regards,
Fred