Lathe not reaching full speed

[Tiger]

My lathe which is a MC900 clone from H & F seems to have a problem reaching full speed. If I'm not mistaken, it seems to have a problem on all speeds ie a 1 on the handle which should be 500 feels like about 300 rpms, 10 which should be 2000 feels like about 1500 rpms. Anyone hazard a guess as to why this is happening?

[RETIRED]

Motor is possibly on the way out.

[unicorn]

Hi, there; I have (yet another) clone, about 12 years old.
I found the belt wears out on the sides, effectively reducing the width, and dropping further into the pulleys, reducing the speed.
A check of the belt should tell you.
(Be VERY careful, the pulleys are extremely fragile)
Have fun, regards, Raul

[hughie]

Most likely its the belt,especially if its the original belt. The Chinese belts arnt worth a cracker, flog out in no time, Ithink from memory A25 .

[Tiger]

Opened up the lathe, I noticed that there is a bit of slack in the belt, it is not frayed but seems to have stretched slightly. It is not the original belt, I bought it from a bearings supplier about 3 years ago.

[joe greiner]

Very, very likely it's the belt. My Harbor Freight 34706 is also a MC900 clone. Higher speed adjustment recently seemed to REDUCE the speed, because it lost side traction. I replaced the belt, and it was almost like a new lathe.

Belt nomenclature is all over the farm. And Reeves drive is sensitive to actual belt length. The 34706 manual lists "M23" (whatever that means), but somewhere I learned that 3/8" x 24" is better. Someday, I'll measure the actual speed. In any event, 25" seems too long (assuming that's what "A25" means). "A" cross section is 1/2" x 5/16", according to Machinery's Handbook.

And while you have it open, be sure to lubricate the pulley shafts. DAMHIKT.

Cheers,
Joe

[WOODY70]

My lathe which is a MC900 clone from H & F seems to have a problem reaching full speed. If I'm not mistaken, it seems to have a problem on all speeds ie a 1 on the handle which should be 500 feels like about 300 rpms, 10 which should be 2000 feels like about 1500 rpms. Anyone hazard a guess as to why this is happening?
Hello Tiger,

You will need to remove the pulleys and belt. Then clean and lube the shafts on the head stock and motor.

You may have to replace the pulleys and belt.(This would be best)

You need to keep this area clean and lubricated at all times as the pulleys need to move freely, This is very important on the motor set as the spring keeps tension on the belt at what ever speed it is set on.

Cheers
David
S/E Qld Woodworking Supplies

[Tiger]

Thanks guys. I am going to try a new belt, even though the current belt looks in reasonable condition.
David, why do you suggest the pulleys need replacing? The pulleys seem to be in good condition. By the way I agree with all the comments regarding keeping the spindle well lubricated, that's why I made up an easy access panel so that I can easily spray the spindle and avoid grime build up.

[WOODY70]

Generally you find that if the machine is of some age the pulleys wear and they become brittle.
When you remove them be very carefull not too break.
Good Luck.

Dave

[Tiger]

Have bought an M23 belt from BSC and given the shafts a good clean, speed seems to be back to what it was, thanks to all for your help, not so lucky with the Bandsaw though. Moral of the story always have a spare belt on hand.

[joe greiner]

Thanks guys. I am going to try a new belt, even though the current belt looks in reasonable condition.
David, why do you suggest the pulleys need replacing? The pulleys seem to be in good condition. By the way I agree with all the comments regarding keeping the spindle well lubricated, that's why I made up an easy access panel so that I can easily spray the spindle and avoid grime build up.

Could you please post a picture of your access panel? It would be a valuable modification.

Cheers,
Joe

[munruben]

Pleased to hear you solved your problem. :2tsup:

[Rifleman1776]

Yes, a good belt is essential. I understand the belts used on industrial air conditioners are the best there are. Might take some shopping to find them. When I had a Reeves drive lathe I found belt wear was inconsistent. Probably dependant on the quality of the belt. In six years I replaced belts three times. But one only lasted a few months. Lubricating the shaft occasionally is important. I used a Teflon based gun oil and found it worked very well.

[Tiger]

Could you please post a picture of your access panel? It would be a valuable modification.

Cheers,
Joe

Hi there Joe,

I have posted a picture of this before. I'll have a look for it and give you the link.

[RETIRED]

There yago Joe and Tiger.
http://www.woodworkforums.com/f8/mc900-modifications-102036/

[Tiger]

There yago Joe and Tiger.
http://www.woodworkforums.com/f8/mc900-modifications-102036/

Thanks, , you beat me to it, again :;.

[joe greiner]

Thanks to both of you. The wing bolts are great by themselves. I haven't been able to figure out how to use cabinet latches at the other connections.

Cheers,
Joe

[cultana]

As mentioned belt notation is all over the place.

From what I have found out the best alignment notation wise with the Chinese 'O' notation is the SPZ series.

Also with the A or M series you can get either a slightly higher or lower speed vs the original using the Chinese provided belt.

In my case I had a O-625 this comes out close to the SPZ-630.
An A-23 has a pitch of 620 vs the A-24 of pitch length of 640.
A M-24 has a pitch of 635 vs the M23.5 of 625
the other issue is that both the M and A series don't sit in the pulleys as per the original O series.
So you may get close to the correct pitch length but the belt will either sit high on the pulleys of sit low due to its profile. Hence odd speeds.

A good reference for belts is this from Naismith:
Naismith Engineering Naismith Catalogues Index (http://www.naismith.com.au/on_tools/naicats/index.htm)
the "Poly-V, V-Pulleys & Belts" catalogue section starts at page 14.