Broken Atlas 10F Countershaft Pulley 560-060 / 9-427

[mmcmdl]

@mmcmdl Don’t go to the dark side! You did the honorable thing. I can’t stand seeing a parted out vintage machine on eBay. I try not to hurl my full judgment at the screen. It’s not like I have blueprints and can prove when they had a 100% whole machine. But I unload a good 90% of my judgment on the seller when I think it was whole ha

That machine went to a very young man starting out in our hobby , and I didn't need the lathe . We both made out great . He got the lathe , I got the extra space in the garage . And it all went for $400 , he was quite happy .

 

[WCraig]

I have not used mymachineshop.net, but i can say that the aluminum pulley would be a better choice than the OEM zamak pulley.
I’d personally pay the extra $50

For a pulley, Zamak and Aluminum (depending on alloy) would likely be more similar than different, no?

In fact, my impression is that Zamak provides a harder surface and thus would not wear as quickly along the walls of the pulley where the belt rubs. Wikipedia says that Zamak 3 is the most common alloy and has a Brinell hardness of 97. Aluminum hardness is all over the map depending on alloy and heat treat. Of course, I'm not a metallurgist and don't even play one on TV!

Craig

 

[Ulma Doctor]

For a pulley, Zamak and Aluminum (depending on alloy) would likely be more similar than different, no?

In fact, my impression is that Zamak provides a harder surface and thus would not wear as quickly along the walls of the pulley where the belt rubs. Wikipedia says that Zamak 3 is the most common alloy and has a Brinell hardness of 97. Aluminum hardness is all over the map depending on alloy and heat treat. Of course, I'm not a metallurgist and don't even play one on TV!

Craig

Zamak can’t take impact, aluminum is superior in that aspect as well as aluminum is not prone to crystallization like zamak.
The Oem pulley was poorly designed and prone to breakage due to thin castings

 

[Ulma Doctor]

I had an 1953 atlas TH42, that was hurt bad by the PO.
Almost all of the zamak components were either broken or crystallized.
I spent a pretty penny to replace the poorly choiced zamak

 

[kcoffield]

I agree with the commentary. There's pros and cons to Zamak versus aluminum. For my Pulley project...

Atlas/Craftsman Lathe Motor and Countershaft Pulleys

I converted my 12” bench top lathe to a under drive cabinet model, and mentioned in my intro and refurb thread here: https://www.hobby-machinist.com/threads/new-caretaker-of-two-12-craftsman-lathes.87335/ …when I bought the lathe cabinet surplus, I got everything except the 2-step countershaft...

www.hobby-machinist.com

....there were a couple other factors. Since I was lost foam casting, Zamak has a considerably lower melting/casting temp so wasn't sure I'd be able to vaporize the foam effectively. I have lot's of experience with aluminum and they were easy parts to cast with that method. The Zamak would potentially have better as cast mechanical and wearing properties. I'll have to heat treat the A356 but 60-70 Bhn(c) hardness should be easily achievable and it will machine and wear much better at that temper. Wrought alloys would be even better.

Best,
Kelly

 

[markba633csi]

Ebay is both a curse and a blessing. If you need a part it's great, but buying whole machines has gotten tougher and much more expensive
It's affected Craigslist too
-Mark

 

[Grinderman]

Maybe I'm the odd duck out there but I really haven't seen the need for the two step pulley system. I have the original large pulley and it's very wobbly so it had to go. I split the difference between the two sizes and went with a 8" single pulley up top and a 3" on the motor. You can get aluminum at most any hardware store or if you can weld the farm stores have hubs and steel pulleys in most sizes. Between the 4 speeds and the back gears, I seem to have all the speeds I need for the stuff I make.
On a side note, I purchased an all steel upper compound slide for my 10F from mymachineshop and am very pleased. Joel is a good guy to work with and makes a decent product from my experience.

 

[JPMacG]

Good comment Ginderman. I never use the smaller sheave on the large pulley.... maybe I did once for turning wood. A single-sheave pulley to match the large diameter would work for me.

 

[WCraig]

Zamak can’t take impact, aluminum is superior in that aspect as well as aluminum is not prone to crystallization like zamak.
The Oem pulley was poorly designed and prone to breakage due to thin castings

Are you referring to "Zinc Pest"?

Zinc pest - Wikipedia

en.wikipedia.org

AIUI, this was strictly due to lead impurities being present in the Zinc component of the alloy. Certainly, there are tonnes of Atlas machines still in use out there that are working just fine. I'm sorry that you had a problem but I don't think it is widespread among remaining machines.

The OP mentioned how his pulley had survived 70 years before an encounter with Dr. Bozo. Trying to remove any large pulley that is tight on a shaft by pulling on the rim is...maybe not the best strategy.

Craig

 

[wa5cab]

Zamak, or more specifically Zamak V or 5, is an excellent die casting material except fir the Zinc Pest problem, which is caused, as Craig indicated, by contaminated feed stock. So only a relatively small percentage of total production would be affected. And basically, if the parts haven't already crumbled, they aren't going to. I will also remind all that were it not for the availability of Zamak or something similar, there would be no relatively plentiful supply of Atlas machines around because they would not have been sold in anything like the quantities that they were. Had Atlas Press attempted to get into the machine tool business competing with South Bend and Clausing without the advantage of all of the cheap to produce die-case parts, they would most likely have been out of business before the beginning of WW-II. And this Forum wouldn't exist. As it was, Atlas tried to make a few things out of Zamak that they shouldn't have. The first group they corrected fairly soon. About 43 years later, those people were probably all dead and the second mistake appears to have been the main reason for shutting down production of the 6" Atlas.