Question re: Craftsman 618 countershaft lever

JID62

JID62

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Greetings,

I am new to this forum and have been absorbing a lot of great wisdom, so first... a big thank you.

I am cleaning and assembling a 618 that I picked up many years ago and never put to use. This is my first lathe. The counter shaft pulley is actuated by a lever shaft that tensions the pulley belt to the spindle. The lever shaft has "flats" cut into it so that (when rotated) it releases/engages tension back to the spindle. The lever shaft itself acts like a cam tensioner. The motor remains running and the counter shaft pulley and spindle are effectively disengaged.

My problem: The lever shaft with flats and the lever itself are missing. I will need to make one out of ~5/8" stock, cut flats into the correct locations, file the part to allow smooth transition from flat to round (cam action) and add shaft lateral stops and a lever.

My questions: What is the circumstance under which I would need to cam the tension in and out? Is this a simple alternative to stopping or starting the motor? Is there some typical urgent scenario that warrants placement of the cam shaft lever near the headstock? I will certainly proceed to make that cam shaft and lever, but I keep thinking of alternative tension options and not sure if there is a reason this original design was used.

Thanks in advance for any help... and thanks again for the forum and the wealth of great information.

JD
 
Not sure what you are asking exactly but the belt needs to be loosened in order to change speeds, by moving the belt to a different pulley groove. The motor MUST should be stopped when doing this. Doing it with the motor running is not safe.
I'm sure you don't need to duplicate the factory dimensions exactly on the lever as long as it functions properly
-Mark
 
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I think the only purpose of the cam/lever mechanism is to release tension on the belts so they can be easily moved from one pair of pulleys to another to change spindle speeds. Without it, the operator would likely have to loosen the motor mounts to change speeds, which would be a real PITA. Fabricating the missing cam/lever shaft shouldn't be too hard. Do you have the dimensions needed to do so?

An alternative would be to replace the entire motor-countershaft setup with a 3-phase motor and a VFD, and then control speed directly by changing the speed of the motor itself. I've gone this route on my wood lathes and love it, but have not yet done so on the Craftsman 101.07301.

Larry
 
On my Atlas/Craftsman 6 x 18, the countershaft cam loosens both the spindle belt and the motor belt. Ity's purpose is to allow changing the belts to different pulleys. There is usually enough drag to keep the spindle turning, even when the belts are loosened. I do use the cam in some circumstances like making springs or winding coils as a clutch where I can control spindle rotation by tension in the spring or coil wire. Another useful trick when threading to a shoulder is to loosen the belt slightly so that if you hit the shoulder, the belt will slip.
 
There are really three reasons for having the belt tensioner built in and for stopping the motor whenever you are not actually cutting. With the belt tensioned, if you try to change speeds, you are almost guaranteed to break something. And with the motor running, belt tensioned or not, if you try to change speeds you are going to lose fingers. The third reason is that if you leave the belts tensioned all the time, they will tend to take a set, and run rough for the first few minutes.

We do not have the original factory drawing of the M6-76 Rocker Shaft nor of the associated parts. The last time that I checked, Clausing still had the replacement parts in stock. I would recommend that you get the replacement from them if they still have it (and no, I do not that I know of have stock in Clausing). If they no longer stock the parts, they will probably email you a TIF or PDF copy of it. If they do, they won't.

There are two reverse engineered drawings of the rocker shaft in Downloads. They are currently at the top of the list or Atlas lathe parts drawings. Neither one details the 51-52 Handle nor the M6-77 Hub or 51-56 Ball. Those you will have to work out on your own. You should also download the 1950 edition of the 612 and 618 parts manual. It is the cleanest copy that we have, much better than the 1966 one.

However, access to Downloads does require Donor status because the Downloads storage fees are a significant part of the sites monthly bill. So before you can download the two drawings that we do have, you will have to donate at least $10.00 (good for a year).

If you do decide to call Clausing and if they no longer have the shaft, handle and ball in stock, ask them for the drawings, and when you get them, send a copy to wa5cab@cs.com and I will clean them up and upload them.

One other point - there have actually been three versions of the countershaft assembly made. The 618 has used the third version since 1939 or 1940. So that is probably the one that you have. But if not, report what you do have here. The second version was used on the Craftsman 101.07301 up until 1957. No first version has ever been reported.
 
Gents,

Thank you all for the great responses.

For safety sake, I do not intend to ever change speeds with the motor running, but I'm glad for the reminder. Novice operators like me need to hear the safety stuff over and over.

I like the hints about using as a clutch... I have a little side project to make an electromagnet and that is a very useful way to do the winding.

For speed control, I plan to use a DC treadmill motor, but waiting to find a "donor" controller. I flubbed up and tossed the original electronics when I moved 3 years ago. The speed change topic may become moot.

Knowing that leaving the belts in tension will set a kink makes sense. I had not thought of that.

Finally, I am going to get my donor status... good to support the forum and all its members and topics. My lathe is a Craftsman 101.21400, so quite sure my missing part is from version 3 of the assembly.

Thanks again,

JD
 
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Thanks for the donation. It might not matter to you but I should have pointed out that there is one area where making a $10 donation (AKA Silver) does not change a NO to a YES and that is access to selling (note that not shown but all members can buy in the various For Sale Fora). The reason for this is more historical than anything else in that back when the current For Sale Fora were set up, we actually had only one donor level, $25.00, which was simply referred to as Gold Member. Later, when we added the other levels, the code was already set up as $25 or more and we may have spent a few minutes looking at typical asking prices but we decided not to try to change anything in that area. So the statement "access to Downloads requires Donor Status" is true and sometimes saves a lot of typing for me, but it doesn't follow that a $10.00 donation buys you the same access in all areas that the higher levels may.

I will also add here that the donation code, which is an add-on, not an original part of the Xenforo code, is not totally user friendly. So if you should run into any of its shortcomings, like you accidentally chose the wrong amount, either live with it for a year or report it in the site help Forum and one of the Admins will eventually try to help you. And when you get the notice that your donation is about to expire, just wait a week until you get the one that says it has expired before you renew it or change it (if that is what you want to do).
 
One other thing - the 101.21400 is the same as the 618 except for badges and nameplates. That is about 3/4 true of an all-original 101.07301 and somewhat less than that of the relatively rare 101.07300.
 
I was wondering how I might "upgrade" from Silver to Gold in the middle of my membership-year, but presently I do not have anything to sell. Next winter I have an SB 9" lathe to spin up and may choose to post it for sale -> downpayment on a small/mini-mill.

I downloaded the very helpful diagrams for the M6-76 Rocker Shaft and expect I can make it myself. Might have my buddy shave the flats or grind them myself. I will file the camming curves by hand.

Thanks again !!

JD
 
Unfortunately...I still smoke cigarettes. 8.00 to 9.00 a pack now. Like buying 4 packs and Im spending close to 30.00

So...my point...
I like this website and when I look at the enormous amount of money I now waste on cigarettes... Well Hell. I surely can Donate at Least 25.00 a year to keep it running smoothly. Hobby Machinist is a great site. Plus...I hate pop up adds.
 
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