too big?

[DWFII]

I have a Jet mini 1014 with a half horse motor--not variable speed. Today I roughed out some black locust that had been curing for about a year. The largest piece (of three) is about 9.5" in diameter and maybe 8" thick.

Has anyone turned that large a piece on the Jet mini? I'd like to hear from anyone who has. I don't want to damage the lathe (it's brand new) nor do I want to overload the motor or set up a dangerous situation. I will be roughing out the bowl between centers...at least at first.

I asked this question...more or less...on WoodCentral, too. But although there is some crossover, it seems like there is a little differnt mix on each forum. I'm just looking for some words of wisdom from people who own and turn on this lathe and who might have thrown that big a chunk on it.


DWFII
In the High Desert of Central Oregon

 

[Jim Carroll]

It will all depend on how heavy handed you are when making your cuts.
Start with your slowest speed then increase as you get the peice in balance. I assume by the depth of the peice that you are going to create a hollow form. You may want to drill out the centre on a pedastal drill with a forstner style bit. Do not try it on the lathe as the weight of the peice and the surface area of the cutter will stall the motor. These motors do not have a lot of tourque down on the lower speeds, because when using forstner or sawtooth bits you need the speed down fairly low to stop overheating.

You then take small and easy cuts with whatever tools you are using . Try to get the speed up to a safe level. The faster the peice is turning the more torque you have and also the easier the cut will be. Remember not too fast as you do not want the peice flying past your left ear.

I would use the Supernova 2 chuck with the 100mm power grip jaws to hold a peice this size. This way I would have a decent spigot to hold onto.

 

[oldgriz]

With that Jet as stated you need to take lighter cuts on a piece that big... especially on something like dry black locust which cuts like concrete... black locust is a very hard wood when dry and even on my 1236 I take lighter cuts than I would on something like green locust or walnut... when these woods are dry they are hard to cut

 

[dkulze]

I've turned many pieces that large on my Mini and have only run into three problems. One is that, if you stall out the spindle but the motor keeps turning, you'll burn flat spots in your belt. Before you know it, you've got a vibration you can't get rid of except by changing belts.

The second is that the low speed is about 500rpm (do you have the VS and will that go lower?). Large, out of true pieces are tough to start out at 500rpm so be careful.

The only other problem I've run into with pieces that large is breaking the tool rest. Watch out for those catches and take gentle cuts.

Past that, the Mini is a kinda bomb proof lathe. By my experience, they way over built it, which I'd consider a very good thing.

Have fun,
Dietrich

 

[DWFII]

Today, I got a few hours and I put one of my semi-green black locust bowl blanks on my new Jet mini for rounding and rough shaping of the exterior.

I am a bit troubled by the results. The blank was about 8 1/2 " in diameter by 4 to five inches high. I set the speed for 500 rpm. But the motor didn't seem to have enough torque. I had a pretty small drive center and it ended up boring itself into the wood, so that may have been the source of the slippage. But even after I tightened the tail stock, it would slip. Increasing the speed to 850 rpm helped a little.

The blank created some vibration...enough that the lathe was shaking a bit and would not remain in one place but not like it was gonna shake itself apart. But bottom line is that I felt the lathe was a bit over loaded.

I finally got the blank rough rounded and partially faced (hard to face between centers when you can't get your banjo under the wood) and I guess I will go with a faceplate to cut the tenon although I can see now that a screw chuck is the way to go in these situations. I'm kind of wondering what lathe speed would be the best for finishing out the bowl?

I appreciate the help and advice I received here...I am a bit worried about the larger blanks now, though.


DWFII
In the High Desert of Central Oregon

 

[Jim Carroll]

How small was the spur drive. It should be at least 1" .
One problem with the spur drive once it slips is that even when puting more pressure from the tailstock this may not fix the problem because the spur drive is not getting any better a grip.
You are better of taking the peice of the lathe and taking the spur drive out and puting the spur drive on your centre position and hitting it into the end of the timber.
This gives the spurs a deeper impresion and better grip. If you just rely on puting it between centres and using tailstock pressure the spur drive does not get enough grip.

Any work that is between centres should have the spur drive hit into the centre of your turning to get a more secure grip on the peice and more positive drive.

With it shaking and rattling on you this is where you learn to rough down your peice very fast. You are trying to get the peice in balance as quick as possible so do not dilly dally. Work quickly but as in your case with the small motor you can only take light cuts .

 

[Rick-U]

Remove bark and use a soft faced hammer

Also... When you "set" the spur drive it should be with a soft faced hammer. I just use a rawhide mallet, but if you need to go buy one I would suggest one with rawhide (replaceable) faces and steel behind (for weight). Hard steel on hard steel can present a hazard, and you don't want to mushroom the end of the spur either. Also, make sure you chisel off the bark and punky wood before you "set" the spur or it will just drill out a plug and use it to clog the spur so it won't bite.