Now I understand why no one changes belts 2

Downwindtracker2

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Here's Dr Fiero 's http://www.hobby-machinist.com/threads/belts-and-why-nobody-changes-them.13084/

Same lathe but I'll add some extra notes. I have a sad belt and leaky seals, so I have the same problems. He mentioned a plug. I thank him for his heads up. On mine to pull the jackshaft, I had to clean the putty off where the pivot shaft goes into the housing, there was no plug. Instead I got lucky, there was a threaded hole in the shaft, 8mm. I cleaned the threads up and used a 8" long piece of 8mm redi-rod and a 6" long piece of 3/4" pipe as a puller . Don't forget the set screw on the underside, above the motor. If you doing one,make sure you grease the redi-rod. It was a hard pull and the nut/redi-rod will gall . The jack shaft was just a push out. I'll replace the Polish bearings. #6204ZZ . Twenty-five years is good service.

Tomorrow I'll tackle the back gear shaft.
 
The belt on my Clausing 100 MK3 got changed about 30 years ago. Not wanting to use a hammer on some of the pulleys I used some 1/2" all thread and a bunch of u shaped collars to dis-assemble and reassemble. Not an easy job, time consuming etc.. Don't remember much, but did use spacers to avoid stress on the headshaft housing to pull and push gears and pulleys off. Really don't want to do it again.
Have a good day
Ray
 
Today was the backgear shaft's turn. This went easier than expected. The eccentric shaft is housed in two bushings. I tapped them back and forth from the outside to loosen them, then tapped the one on the end flush with the casting. The one on the bed side I took out by hand.

Next is the spindle, but I'm stuck at the moment. I'm awaiting a 1/10 dial indicator to measure the bearing clearance from the factory. The spindle shaft bearings are on what I call K-tapers, so I did measure the distance from the shaft end to the first lock nut. The jam lock nut came off easy enough with a hook spanner.
 
The spindle came out with a surprise. It has just cup and cone bearings, like Timken . Much easier to set up. I did find that the clearance was only 1/10. When I took the belt into the Motion Canada, a bearing store, the used First Rope Taiwanese belt B-33 was the same length
as a Gates B-30. Which was shock. Thankfully before buying a B-33, I had it checked !

Now I'm waiting on seals, belt and sheave. , three of the four seals are 12mm, another special order. I'm changing the motor out to a 3 phase for VFD. The 2 hp Baldor has 5/8" shaft instead of a 3/4" that is on the original motor, so I have to make up a two step sheave. The solid hub larger sheave comes from States.
 
I am having a flash back to earlier in the year. I purchased a belt for my milling machine around March based on the original code being "B-35". I replaced this with a cogged belt, a BX-35 - which was too big. I just went to check and you will not be surprised the belt was
First Rope" company and it was made in Taiwan like the milling machine.

You could purchase or make a spacer for the new Baldor motor and cut out a section for the key. You will need to make a deeper key.

My milling machine also had original 3/4in shaft on the non-standard motor. The seller had replaced with a 5/8in dia shaft motor and made a spacer and deeper key. He thought the original motor was going to die as it had a noise. I took it apart could not find anything and replaced the original motor since it runs quieter than the replacement.

If you were on this side of the border I would send you the spacer, but it is expensive to ship across the border.
 
Thanks for the offer. But if I was still working, I'm retired now, I would have suggested replacing the sheave. It looks rough and there's black dust on the motor. It's a 25 year old lathe. If I was desperate, I would use a couple of 5/8x3/4 bushings., an off the shelf purchase, and just cut out for the keyway.
 
Well it's back together now. I haven't tried it out, I have yet to install the VFD and tach. But the wrench pulling is over. For the motor sheave, I'll use two cast iron solid hub sheaves, it's two speed off the motor. I'll cut, then mill the hubs off and bolt the two together . Voila, a correctly stepped pulley.

Since I had the spindle out, I decided to replace the bearings, they are only cup and cone roller bearings. Nothing fancy or expensive. I used Timken instead of Polish made Tam . # 30211 and #30212. One was marked as 7212, the 7200 series is angular contact ball bearing. I guess they got a deal on mismarked bearings. The spindle comes out and in on the bed side. For the bearing cone, I heated it under a heat lamp and put the spindle in the freezer. It slid on. Remember to oil, it helps your karma.

The back gear is on eccentric which also adjusts the backlash .

The jackshaft bearings are #6204 ZZ, I used SKF brand. The heat lamp and freezer again.

While most of what I worked on was "loose", easy to put on and more to the point , easy to assemble at the factory, the pivot shaft required a hammer. I think there was some misalignment . It had been hard to remove as well.

The seals are metric ,#55x75x12, #60x80x10, #65x85x12, #80x100x12 . If you notice three of them are 12mm thick, standard thickness for seals is 10mm, so they were special order.

The covers had glued paper gaskets. They were also the retainers for the cups. So I used paper gaskets and Permatex , instead of a lazier RTV gasket maker.

When I checked the belt against the old one, the B-30 Gates he had sold me was one number off. He had measured the old one at the bearing dealer. It really a B-31 . The First Rope it came with was marked B-33. Again they must have gotten a deal on mismarked belts or they were made poorly.

All in All, not too bad to rebuild the headstock. Simple ,almost crude, acceptable machining quality.
 
Apparently belts were originally thought to last forever. My Fosdick jig borers look like I would need to totally take apart the spindle, half the top, and front end to replace the belts. No markings on any of the belts, they could very well be from the 40's.

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Most engineers think the machines they design are so well designed as to be tool proof. Yeah right. They should be made to work on them. As a millwright, engineers and machinists didn't usually make my Christmas card list.

A couple of times I've seen the use of split top bearing, I think they were Cooper ?, so the belts could be changed on jack shafts. But those were Finnish designed machines.50Hz vs 60Hz on a pulp bleaching system. The Cooper bearings were so good that over my working life, I installed three sets because ordinary roller bearings were failing regularly. Problem solved.

Those belts look like they could be 3V series. 3V and A are about the same size, it's just that V series have a different side profile. There are a few different series of V-belts , high performance newer 3V,5V and 8V, the old letter series, A,B,C. My lathe was one of these. and metric. I don't know much about the metric ones. On washing machines and cars you would find the fractional horsepower L series 3L,4L. 4L were the same as A except with a different numbering system. Then there are the toothed timing belts.
 
Somewhere on my to-do list, is to clean and grease all the bearings, and possibly replace the belts. Four heads, equals six teen belts. I guess they went with the 4 belts, so the tension is not as critical, since there is no way to adjust the tension. 1HP 3 phase motors, geared down to 110 RPM for the lowest speed, gives it gobs of torque to transmit through the belts.

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