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Increased HP on Jet Mini

W

Wayne Spence

Joined
Jun 13, 2009
Messages
217
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Location
Denver, Colorado
I have a Jet mini lathe, 1/2 hp (questionable) with the bed extension. I have turned two pedestals each about 40 inches long and bases 8 and 9 inches. They were rather light being of spalted pine. What do the experts think of raising my hp to one on the condition I can get a 1 hp motor that will fit.?The belt seems a bit on the thin side to transmit the extra hp but I am guessing. Am I better off just getting a lathe with greater hp? Comments are appreciated.

Wayne Spence
 
Ideally you would change the pulleys to a 6 land from the current 3. Then put a 1hp motor on. Anyone know what size belt the 12" minis are using. I've turned on one and they have 3/4 horse motors but I didn't look at the belt driving them.
I'm planning to change my Nova Comet to 1hp VFD motor and controller. I haven't started looking for the pulleys yet but had planned to go with a pulley with fewer steps but more gripping power. I think I might be able to squeeze a 3 step 6 land pulley in the space I have. 3 steps with VFD should give me enough range and power. My lathe will have about 40" between centers.
 
Motors, belts, bearings, machine frame, etc., are typically designed/selected as a matched set. Change one, and everything else goes to pot. At best, you will shorten the life of the belt and bearings, in exchange for a modest performance "improvement." A Volkswagen Beetle with a Hummer engine will run great for a while, but a very short while - possibly even immediate failure.
 
Joe I have to respectfully disagree. Now if we were changing from 1/2 horse to 3 horse yes. I don't think doubling the horsepower on lathes this small will hurt the bearings etc. They have a 1" spindle just like the 16" 2hp lathes. The bearings might be a little smaller and not handle as big a load but then the lathe is 10" or 12" swing and that's probably the limiting factor.
If you buy a 6 land pulley it will be designed to take that load as well as the motor and shaft. The only limiting factor in my mind would be the size and type of bearings and the size of the shaft where the pulley and bearings are supported. However the shaft size is probably the same as a larger lathe because they still have a 3/8" through hole and #2 morse taper. That narrows it down to just the bearings. On the Jet and Rikon mini's the bearings are extremely easy to change so upgrading would be easy if necessary.
All being said and done the best bet obviously is to step up to a bigger lathe but in my case I'm trying to keep this lathe small for travel purposes. I already have a large lathe.
 
I think by the time you spend the money, time, engineering, shipping charges for special this or that. A new lathe might be cheaper. and less down time.imo
 
My first mini was a Jet VS and I could stop it with my hand. I doubt seriously it had more than 1/4 hp, no matter what they claimed. I'm now using a Delta 46-460 with a real 3/4 hp and over 12" swing. Several places are selling them for $600 or less. Save your time and effort, and just get a 'real' small lathe!
 
motor change

my suggestion is to watch the curb or garage sales for treadmill. a little research and only a couple of bucks will make a dc controller for it. ie a good dimmer switch and a rectifier from radio shack. a minor mod usually to the original motor pulley and you are set.
 
john lucas said:
Joe I have to respectfully disagree. Now if we were changing from 1/2 horse to 3 horse yes. I don't think doubling the horsepower on lathes this small will hurt the bearings etc. They have a 1" spindle just like the 16" 2hp lathes. The bearings might be a little smaller and not handle as big a load but then the lathe is 10" or 12" swing and that's probably the limiting factor.
If you buy a 6 land pulley it will be designed to take that load as well as the motor and shaft. The only limiting factor in my mind would be the size and type of bearings and the size of the shaft where the pulley and bearings are supported. However the shaft size is probably the same as a larger lathe because they still have a 3/8" through hole and #2 morse taper. That narrows it down to just the bearings. On the Jet and Rikon mini's the bearings are extremely easy to change so upgrading would be easy if necessary.
All being said and done the best bet obviously is to step up to a bigger lathe but in my case I'm trying to keep this lathe small for travel purposes. I already have a large lathe.
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OK, I probably overstated it. But the belts in particular are selected for HP ratings. Bill B is better qualified to do the math, and a more robust belt cross section might provide a longer time to failure, with pulleys to match. Formulas at Machinery's Handbook, 24th edition, p. 2285.
 
There's obviously a fine line between how much time and money you are willing to spend to upgrade a lathe vs just buying a new one. In my case I love my old mini lathe and upgrading it is the better option because a new lathe that does all I want to do does not exist. Besides, I think I love tinkering almost as much as turning.
If you want to upgrade a jet or rikon you could easily spend more money than if you simply sold the machine and bought one of the new bigger hp models. I think you would be talking $200 to $300 max. on the difference unless you just couldn't get anything for your old lathe. Mini lathes seem to hold a good resale value.
 
I have to aggree just upgrade, next you are going to want more swing, etc... if you mod it and it has less value. You can sell it now and upgrade for not to much money. Also I don't know anyone who had modded them so I don't know what woudl break but I would guess it might be ok, but if you crack a berring mount or something you are out the lathe and startign over.
 
Thank you all for your comments. In 1956 I moved to Los Angeles, bought a 34 Ford coupe and put in a 48 Merc v8 with some modifications. It went like the roadrunner when it went. I believe my choice has been made as I just received a check for my prized Swiss super accurate Olympic pistol.
 
john lucas said:
Bummer, I'd love to have the pistol.
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John-After your comments I am going to modify my shopsmiths. I bought two for $50. They are now arranged so they are almost butted tailstock to headstock end. The toolrest is on the headstock end (part that noes notpivot)of the second smith. I have turned a 30'' piece this way but the piece must be verywell balanced to begin with. The next modification is to reduce the rpm to under 250. Will send in a photo when complete if promises are to not laugh.
 
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