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Geared head vs belt driven lathes
- Thread starter Doc
- Start date
- Joined
- Nov 16, 2012
- Messages
- 5,596
Most shop lathes have at least one belt from the motor to the gearbox so, to some extent all are belt driven. Of course, you're asking about lathes having belts on the spindle. If I had to guess, they originated out of simplicity. Gears were/are harder to make. There are some pros & cons. Belts can introducing vibration as they flap. Gears are harder to keep lubricated. Changing belts for different speeds usually requires some re-tensioning and gears are changed with the turn of a knob or shift or a lever. There's probably a bunch more examples on both sides of the fence.
I've had both and don't plan to go back to belts even though they are quieter.
Ray
I've had both and don't plan to go back to belts even though they are quieter.
Ray
Thanks Ray. I'm still investigating wich lathe to get as a first one, hence the question. Currently looking at a JET 13x40 or an Optimum machine (eastern manufactured German lathe - if that makes sense). However, the JET lathe has a lot of tooling accessories included, so I'm thinking that obviously has to be a better bet for a beginner.
To answer your first question, "belted" power lathes go back thousands of years and are still in use in aboriginal cultures. I got to see one in action in South America where an Indian was turning an arrow shaft which he had wrapped with a piece of animal gut attached at one end to a convenient tree limb ) bowed down and the other end to his big toe and the shaft was trapped in some low hanging limbs when he pulled down with his toe, the shaft rotated in one direction and when he lifted it, the opposite direction. Using a chipped stone edge, he proceeded to very quickly work the shaft to the desired size and went on down the jungle path. Later. civilations used water mills to rotate shafts and transferred the rotation to overhead leather belts Still later (during the Industrial Revolution) we moved to steam driven shafts and still later (late 1800's) electric motors replaced the steam engines. (Still overhead belt driven machines) In the early 20th century we started seeing gear driven machines which were more compact. (still belt driven between the motor and the gearbox) To your second question which is better, they're both excellent systems but it really depends on what you want to do with the machine. If you're looking to a general purpose machine ( like the 13X40 lathe) buy the best you can afford. Don't be lured by cheap as you'll get exactly what you paid for. Buying a high quality used machine in good condition would be my choice. Weiler, Logan, , Hardinge, Takisawa, Mori-Seiki ( Yes they actually made small toom room lathes) As my Hardinge HLV-H is a belt driven variable speed machine I can tell you that the belt system is very, very smooth. All gear driven machines without exception have some degree of vibration/ noise associated which their operation. (Although they're still very accurate and robust) For general purposes, I would have to go with the gear driven machine.
My main lathe is a Chinese SC4, which for the most part is excellent for what I do with it. It has a belt from the motor, but is gear driven just before the spindle.
I have observed a faint radial pattern on workpieces after careful facing, that appears to be a 'print' of the last gear before the spindle. I can count the number of radial 'sectors' and it does match the gear tooth count of the last gear, so it seems to be the case, but I am interested if anyone else has observed this on their gear driven lathes after careful facing cuts. More particularly, if they have seen it on belt driven lathes after the same cut.
If I am correct about the last gear printing on the facing cut, then it certainly is a negative of a gear driven lathe. The pattern is very faint, only a micron or two deep, but it is a bit of a pest when polishing/finishing. The irony is that if the lathe did not have such a superbly smooth cross slide power feed, I probably would not be able to see it!
Am I correct in thinking that one of the most desirable attributes of the Harding HLV is the belt drive, combined with the electric motor power feeds? (Amongst its many other fine qualities!)
I also have a belt driven 9x20, and it shows no such pattern, but then it has no power cross feed either, so it is difficult to achieve as clear a facing finish as my SC4, so it may be there, but masked.
love to hear of others observations.
Cheers
I have observed a faint radial pattern on workpieces after careful facing, that appears to be a 'print' of the last gear before the spindle. I can count the number of radial 'sectors' and it does match the gear tooth count of the last gear, so it seems to be the case, but I am interested if anyone else has observed this on their gear driven lathes after careful facing cuts. More particularly, if they have seen it on belt driven lathes after the same cut.
If I am correct about the last gear printing on the facing cut, then it certainly is a negative of a gear driven lathe. The pattern is very faint, only a micron or two deep, but it is a bit of a pest when polishing/finishing. The irony is that if the lathe did not have such a superbly smooth cross slide power feed, I probably would not be able to see it!
Am I correct in thinking that one of the most desirable attributes of the Harding HLV is the belt drive, combined with the electric motor power feeds? (Amongst its many other fine qualities!)
I also have a belt driven 9x20, and it shows no such pattern, but then it has no power cross feed either, so it is difficult to achieve as clear a facing finish as my SC4, so it may be there, but masked.
love to hear of others observations.
Cheers
- Joined
- Nov 16, 2012
- Messages
- 5,596
Have never seen or heard of this but I have no reason to doubt you... Have you taken it apart and see if the gear can can be adjusted, replaced or possibly polished?
Interesting problem to solve...
Ray
Interesting problem to solve...
Ray
- Joined
- Nov 21, 2012
- Messages
- 793
Traditionally belt drives have been used to isolate vibration from the drive to the headstock. Most expensive lathes will have 2 - 3 belts from the motor to the clutch / headstock in order to provide a superior finish at high speeds.
When higher speeds are required the lathe may even have the option to change to a belt drive from the clutch to the headstock / gearbox, further reducing vibration. If anyone reports poor finish due to belt flapping, this may be the result of poorly balanced belts, loose belts, worn or old belts, or unmatched belts (although modern belts from the same manufacturer won't usually need to be matched).
In the example of the Colchester Chipmaster:
http://www.lathes.co.uk/chipmaster/
you can see how the drive and headstock / clutch / gearbox have been seperated using belts. When a heavy cut is required and high torque is needed, the option is available to change to gears. This option is often not available on cheaper machines that are belt driven and therefore these machines can suffer from belt slipping. this is often the reason why these machines have a higher low speed than machines that can be changed to gear drive. A nice thing about belt drive on high speeds is the reduction of gear noise which can be quite loud.
Nothing I have written is a hard and fast rule however the many lathes I have seen tend to follow what I have noted.
Paul.
When higher speeds are required the lathe may even have the option to change to a belt drive from the clutch to the headstock / gearbox, further reducing vibration. If anyone reports poor finish due to belt flapping, this may be the result of poorly balanced belts, loose belts, worn or old belts, or unmatched belts (although modern belts from the same manufacturer won't usually need to be matched).
In the example of the Colchester Chipmaster:
http://www.lathes.co.uk/chipmaster/
you can see how the drive and headstock / clutch / gearbox have been seperated using belts. When a heavy cut is required and high torque is needed, the option is available to change to gears. This option is often not available on cheaper machines that are belt driven and therefore these machines can suffer from belt slipping. this is often the reason why these machines have a higher low speed than machines that can be changed to gear drive. A nice thing about belt drive on high speeds is the reduction of gear noise which can be quite loud.
Nothing I have written is a hard and fast rule however the many lathes I have seen tend to follow what I have noted.
Paul.
I have the same radial spokes when autofacing on a belt driven Boxford.
It took a completely superfluos and expensive and difficult change of main bearings before i counted the number of spokes 24.
There are 24 teeth on the rear end of spindle for driving gear train to norton box.
Handfeeding No spokes
There is only one lathe Schaublin and it has a belt driven spindle and electric feed drive.
It is regretably out of reach for my pocket.
Niels
- Joined
- Jan 1, 2013
- Messages
- 185
The problem with belt drives is they invariably have backgears for the slower speeds, and it is an inferior gear drive. Not well lubed or protected and a general PITA. But in the general scheme of things, belt drives are okay for the home shop. Would not think of buying one for professional shop use.
Bill
Bill