Mini Jet heating problem- help please

[Touchwood]

Recently I bought myself a mini jet lathe (not variable speed, alter speed by changing the belts). After waiting patiently until my birthday to open it I was disappointed and worried about how hot the wheel, the threaded bit for the face plate and the head stock got in less time than it takes to turn a pen.

As a cooking teacher my hands are use to handling hot things - these areas were getting too hot to hold. So I took it back - result - "the bearings must be stuffed" so they were replaced and "we ran it for hours and its fine."

Guess What - before I finish a pen the wheel, and all parts to the morse taper bit of the pen mandrel are so hot you can not hold onto them. I am not a slow pen turner, I'm turning wood, the lathe is on full speed.

Help please other Jet owners before I lose the plot - do your lathes get that hot? Any ideas on what it could be so I can take it back again and get them looking in the right place!!!:no:

Jenny

[Dan]

Does it still heat up if you run it without a blank or mandrel loaded in it?

[Touchwood]

As I'm waiting for some glue to dry I'll go and try that ( as I don't usually turn it on with nothing in it) and see.... back soon

Jenny:2tsup:

[Touchwood]

Yes, ran it for about 3 mins and, while it was warm to start with as I'd just been using it, in 3 mins it was once again too hot to comfortably hold onto.

JD

[Barry_White]

I have turned as many as 8 pens on the trot and mine doesn't get that hot. In fact when I am sanding I lean my forearm on the head above the bearing without any problem.

When I bring the tail stock up to the mandrel I push it up hard and tighten the big lever on the tail stock and then wind the handle so that it puts enough pressure on the live tail centre so that it will spin on its bearings and not on the pen mandrel. The tail stock gets a little warm but not so that you can't touch it.

Have you got enough pressure on the belt so it doesn't slip. If so I would guess that it still has a problem. Are you sure they replaced the bearings.

[DJ’s Timber]

Does the shaft spin freely with the belt loosened off completly and with nothing on it?

Your should be able to spin it quite easily with the tip of your finger and thumb like when you click you fingers.

[Touchwood]

Barry White - thanks for the thought - I'll go for broke on tightening the motor down on the belts; as to the bearings, they handed me two bearings that "were replaced". They seemed to be free flowing and no obvious 'grab' could be felt in either.

Off to the shed again ..

Jenny

[Touchwood]

Does the shaft spin freely with the belt loosened off completly and with nothing on it?

Your should be able to spin it quite easily with the tip of your finger and thumb like when you click you fingers.

With the belt completely loosened I can spin the shaft using the hand wheel, however as soon as I remove my hand /force it stops. In this process it would do under a 1/2 revolution. It doesn't continue to free wheel, but it doesn't seem to be catching ot uneven.

Have you got enough pressure on the belt so it doesn't slip.

sigh..... even with lots of pressure on belt, within minutes she was heating up again.
JD

[DJ’s Timber]

I wonder if the hand-wheel has been overtightened putting to much load on the bearings. If you have your manual, it says on page 7 under Belt Replacement under step 8 which is on the next page



Thread the handwheel onto the spindle leaving a little space between the handwheel and headstock. Tighten set screws


Another thing to look for is that the top and bottom pulleys are lined up with each other

[Touchwood]

I wonder if the hand-wheel has been overtightened putting to much load on the bearings. If you have your manual, it says on page 7 under Belt Replacement under step 8 which is on the next page

At this stage I'm willing to try anything, HWMBO wondered something along the same lines - (he's a musician not a shed man) :D ......have manual, will try. Thanks.

Another thing to look for is that the top and bottom pulleys are lined up with each other
These do appear to be in line.

JD

[soundman]

Sounds like a bearing pre load problem to me, unless there is something fouling.

What sort of bearings does it have, ball races, tapered rollers, or something more sofisticated.

cheers

[rodent]

bearing pre loading or miss alighnment .? try slack the belt off then put a piece of wood in front of your shaft and give it alight wrap with a hammer gently does it then spin it up and see how it goes .

[Stuart]

How's the motor heat? Is it transferring? (It would have to be bloody hot to transfer that fast, so you'd know) - The motor should become warm, but you should still be able to place your hand on it for a few minutes without it causing pain.

Mine does not get any hotter than what is being generated by the actual heat from the chisels / sandpaper etc - I would definitely notice an excess of heat.

[Coldamus]

I only had mine for a short time as I bought it to see whether wood turning was for me. It wasn't.

However I turned a bowl with it and, being a newby, that took me several hours continuous. I did not notice any heat at all. The motor may have been warm but none of the working surfaces or controls were.

[OGYT]

I don't have a mini, but that sure sounds like a case of the bearings being too tight, to me. If you can't turn the shaft easily, like the man said, like snapping your fingers, the bearings are probably too tight. I don't know how your manual reads, but there may be an item specifying how to tighten or loosen the bearings. Just a thought.

[Hambone]

Hi Jenny,
I have had a little Jet from the time they first were sold in W.A .I have replaced the bearing once as one was a little noisy I think your problem is the overtightning of the hand wheel .There are 2 small spring type washers one at the hand wheel and one on the other side of the head stock .If the hand wheel is overtightnd these washers will put side pressure on the bearings causing them to run hot. There are 2 grub screws in the hand wheel slacken them off loosen the hand wheel a little untill the shaft turns freely then retighten them .I think that will solve your problem.If you don't tighten the grub screws the hand wheel will rattle and worry you again.

Regards ,
Ron

[Touchwood]

WOW :D thanks for all the advice ... unfortunately the school term has just started again and I'm dragged (kicking and screaming I might add) out of the shed and back to work :~ :~

HOWEVER, I will be heading up with manual and advice as soon as I can to try the various suggestions ... will keep you posted when I eventually solve the problem!! (note the optimism!!!:wink: :wink: )

Jenny