The turbocharged 14.5

So far I've only run it 460 and whatever the next step up is. As long as I stay within the design limits, I don't see a problem. The issue will be if I can't get it slow enough to turn a large object.

The driven pulley is fixed. The drive pulley has a large internal spring, the belt tension wedges it open. Adjust the motor down, the pulley opens, and you get a lower ratio. But I have to get the motor off the floor before I can try more.

This seems to be what I have, if a bit shinier.

http://www.speedselector.com/

http://www.speedselector.com/engineering/index.htm

Ah I see, so it's an internal spring. Well that belt looks like it has seen better days, try getting one that is shorter. That would allow more range to lower the motor

The flat belt is pretty knackered also. I'm going start there with a belt at my measured 62.5". Current is 65". we'll see what happens from there.... might end up replacing the pulley set, as I just thought of one issue with the over drive. I may be running with the back gears constantly in.

The driven pulley looks too small so someone trashed it.

A shame they torched the door so you now have a shopping list.

Suspect some clown wanted higher speeds and murdified it.

Do pull bearing caps to inspect.

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AHa! You have the venerable "Reeves Drive" type variable speed control. You adjust speeds by changing the diameter of the lower pully with a small motor and gear attached to the lower shaft. The pully opens and closes, changing the diameter and pully ratio. Looks like you are missing the lower drive motor to change speeds. I think you could buy the drive motor and retrofit.

These are very common in industrial settings, such as conveyor systems that need to be slowed and speed up for different work loads. Not so much on lathes. Google " South Bend Fourteen" lathes. These were built with the same style VS system in the 70's and 80's, but I suspect SB made their own proprietary drive, as mine at least is not a Reeves brand drive.

Also there is a SB Fourteen rebuild thread either here on the SB thread, or over on .Chaski that will give you some info on the drive unit. My SB Fourteen turns from around 50 RPM to somewhere near 2000+, however, the upper drive pulley connects to a two speed transmission, and has a Hi/low lever for switching between the two basic speed ranges. Because these work with a transmission, I doubt you will be able to find different size pulleys, if you wish to alter the speed range. Do you have such a transmission? This is how you would achieve a full range of speeds.

The belts are actually not flat, but thick and wide v belts. The edges of the belt are cut at something like 22 degrees to grip the countours of the pully. Readily available online from gates and several other respected manufacturers.

One other thing - change out the belt if it makes noise, or doesn't hold RPM whilst turning. particularily listen for a vague thumping sound, like a bearing starting to go bad deep inside the machine, or pre load on the spindle out of adjustment. It's not. It's the belt. ( As I found out after weeks of trouble shooting). The rubber and biase eventually gets stiff and inflexible and impedes performance. New belt makes a world of difference.

Glenn

For what it's worth, this is how my heavy ten is set up from the factory. Your 14 should be the same just bigger.

You can see that the lower pulley on the motor is a "V" pulley. It has 2 sizes for High and low speed. The upper pulley is also a 2 sized pulley but it's flat and the inner part of the "V" belt rides on that flat. I have never had it slip.


Here it is with the belt installed. I put a new cloth wrapped power equipment belt on it and it works well. I think as it is now that it's on the high speed position.

Great!!! Thanks!

The flat belt I'm replacing is the original SB drive, not the v-belt on this primary drive. I'm used to this style drive from my days at the track. Old F440 (440cc snow mobile engine) used an inertia controlled variable drive; basically a very primitive CVT. Little old two stroke screaming at 7000rpm from 0 to 140mph. I'll dig further into this drive when I get time. Way to many irons in the fire right now. As long as I can get the speeds needed for the jobs at hand, it functions.

BTW, the hack that did this modification was the engineering department at Penn State.

Here's what I did for the flat belt. There's lots of options but I chose this because I can source an automtive serpentine belt cheap and cut it to the needed length. They don't slip either, run quiet too the way that I joined it. I have not had much luck with any kind of glue, but this has held up well. I even had to cut the stitching and remove the belt to move the lathe when I moved, just put it back on the same way.

I used this braided picture hanging wire because it was cheap, available at the local big box store, and it flexes without breaking or kinking.

I tinned the end with solder so I could pull it through the holes I drilled in the belt without fraying it.

I drilled the holes far enough away from the edge that they won't tear out. I did it so the wire would lay in the grooves and not make contackt with the pulley's

Flipped it over and put a drop of solder on it to secure it.

And this is how it looks on the pulley's.

Again, your 14 is just bigger with 4 pulley's instead of my 10L's 3, but you can still source a belt that is wide enough for your pulley's. Just measure the width and loop a string around the pulley's and measure it to get the length. Really easy and it works great. Pluse if you ever need to remove it you won't have to buy a new belt, just re stitch it.

Funny about the hack, lol. I work a part time job in a power equipment shop as a counterman. Ever try and sell parts to a engineer!

Thanks Greg. Right now I am seriously time-poor. Cleaning out the in-laws estate, building amother-in-law suite, moving into said estate and building the shop. And a full time job and a home business. So I went with a flat belt off ebay for right now. I have a bunch of turning coming up, all in the 1.5-2.5 range. I should be fine for right now.

And conversely, ever tried to get useful concrete engineering data out of the salesman?