mini metal lathe -- tool post for woodturning

I just purchased a used Clarke 7x14 mini metal lathe. It appears to be one made by the same company that makes the Grizzly and/or Harbor Freight.

I'm going to take some training from a Machinist on it ... have zero experience! Just finished reading O'Brien's "How to run a lathe ..."

I do woodturning ... therefore I would like to have a tool post for it to allow me to be set up - when not doing metal -- as a station to turn pens using my EWT carbide cutters. Has anyone made a tool post for this size lathe?

Thanks
Gerry Stover

Wood dust is not good for metal lathes. It tends to wick up oil and rob the sliding precision surfaces of lubrication. Also certain woods, especially roots, can have a lot of sand/grit in them which won't do the precision surfaces any good. Oak contains rust-inducing tannins so you may want to avoid it.

On the rare occasions when I hand turn metal on my lathe, I improvise a rest by mounting a length of metal in the boring bar holder. This arrangement allows the rest to be easily repositioned by simply turning the holder.

Metal lathes generally run at speeds much lower than those used for wood lathes. Will you have enough speed to turn small diameter wood such as pens and get a good finish?

Marv is correct.
Machine tools depend on sliding surfaces and lubrication far differently than woodworking equipment. Incidental use is feasible if; 1] The ways are fully shielded by plastic such as food wrap, oiled for adherence of desired surfaces. 2] Sufficient RPM is available for the small diameters of pens. 3] Duty cycle of motor isn't exceeded. 4] Lubrication and cleaning are attended to accordingly.
All manner of examples pertaining to homebuilt wood lathes are in HMT.net. They shouldn't occupy much space, power requirement, or cost. You'll find yourself better served by two machines, I think.

Wed 10 Aug 2017 0753;
A recommendation occurred to me in respect to this topic. I'd move carriage far right and place tailstock [if needed to work between centers] inboard, and use 1 thru 4 detailed above. This solution would require a self supporting toolpost, independent of crossslide/ compound, quite like a wood lathe uses normally. This alleviates far more issues connected to dust, lubrication, and fitted surfaces.
ultralightflyer allows daughter to use lathe for wood turning in post #4 with restrictions. That achieves many positives; including the 'grooming' of a craftsperson, maybe even a tradesperson, but a new maker none the less.

I've always believed in STEM education, yet feeling it falls short of creating and reinforcing the critical work force to support it.

Little Machine Shop sells a wood tool rest and center for the mini lathe. I just bought 1 for my daughter to use on my mini lathe. To prevent any problems I INSIST that she cleans up and wipes down the whole area and lube the bed and anything exposed to wood particles when she's done. Here is a link to LittleMachine.Search For... - LittleMachineShop.com

Attachment 19117
This is a small tool rest I made to turn up some odd jobs. As said by the posters before me if you do clean thoroughly and oil after use.

Hi Gerry,
Little Machine Shop sells parts for these lathes, and has all kinds of accessories and tooling! They are also the go to for information and projects plans pertaining to these. Chris is a wealth of knowledge.
Cheers,
Rick

Thanks ... I will abandoned that idea for wood but what about acrylic?

Yes, it turns nicely, some years ago I turned several intermittent positive pressure valves from acrylic bars, acrylic is not abrasive. Regarding turning wood on a metal lathe, don't avoid doing it. We all use tool post grinders to precision grind round parts, covering the ways and compound with rags. Grinding swarf is much worse than anything found in wood, except, maybe industrial diamonds. I have been grinding on my South Bend 9" lathe occasionally for the past 67 years, with no harmful effects.
Since you are not generating red hot sparks, slightly oiled rags will do a great job of trapping particles, while lubricating the ways and compound. Just don't store oiled rags
bunched up, indoors, Hang them over something preferably outside, to avoid heat building up heat leading to spontaneous combustion. In the shop, oily rags are stored in a steel drum with a tight lid.

I agree. Turning wood isn't the issue, the effects are. A bit of preparation insures those won't cause problems.

As far as toolpost grinding I differ soundly. While an old practice and recommendation, rags are not reliable. Rags, oiled or not, are generally ineffective barriers to abrasive grit, the bonding resins, and metallic fines [particles] produced. The density of cover material has to be higher than the smallest particles. Examine back side of an engine air or oil filter!
Oiled, I use wax paper, newsprint, plastic food wrap etc to attain a far more effective 'seal' against particle invasions. Drape over required surfaces in the same manner shingles are laid to shed unwanted material, to be removed in the reverse they are applied.

So far, I've been able to avoid grinding on the lathe altogether. While I realize there are jobs that may require it, it still seems like a process fraught with hidden possibilities.

One thing I've always wondered about...What, if any, are the dangers of lathe motors ingesting airborne metallic dust created during grinding? Many small lathes have the motor axis quite close to the spindle axis so, if they have a cooling fan, as I expect many do, they are all set to eat whatever dust is coming off the work. This could be an issue with sawdust as well.

It's not the motors that can be damaged, but the ways of the lathe. If you do use a tool post grinder on your lathe cover as much of the ways as possible WO creating a situation where the cover could be caught in the grinder. Afterward remove, clean & re-oil all the wipers and give the ways and cross slide a cleaning like none other.

mklotz wrote "One thing I've always wondered about...What, if any, are the dangers of lathe motors ingesting airborne metallic dust created during grinding? Many small lathes have the motor axis quite close to the spindle axis so, if they have a cooling fan, as I expect many do, they are all set to eat whatever dust is coming off the work. This could be an issue with sawdust as well".

Hadn't even considered motor ingesting grind dust. Commercial equipment normally are TEFC, and/or shrouded by castings immune to such dietary intake.
Never ground on a lathe, mill or non-grinding machine I've paid for. My floor plan provides a room enclosed and ventilated just for abrasive pieces of work.
Not including in-laws...

I have a mill that I've owned for over 25 years. I work on whatever with it. Wood, metal, plastic, I grind sometimes. Just clean and oil your machinery regularly and you'll be far ahead of what most production equipment is made to deal with. Tools are made to be used. Anyone that tries to tell you anything different is a fool. They'd all have heart attacks if I ever took them to E P Heller's shop. He works all in carbide. Someone's gotta. Talk about abrasive grit.

thank you for info

OK, I am a retired Toolmaker with 42 years in the shop. Here are a couple of thing to consider.
My favorite machine is the lathe, but it is by far the most dangerous machine in the shop. On industrial lathes you can be running high HP motors with very high torque, and they will wind up a shirt faster than you can blink. I don't mean to imply anyone is dumb, but I have seen some people that have 15 years in the shop and had their shirts tore right off, one time he was missing 2 fingers, and a broken arm, shoulder, and 2 cracked ribs. Another one was using a file without a handle and it ended up embedded in is arm wit just the last inch sticking out.
First off, keep your work as close to the jaws as possible. I used to cringe when I would see Adam off of Mythbusters have a piece of plastic hanging a foot away from the chuck.
Second, if you want to cut any type of plastic, use a really sharp tool, not an insert unless it is an insert specifically for turning plastic. Have a good sized radius on the tool, (IE 0.015"). A sharp point will give you a bad finish, and has a tendency to grab, sometimes breaking the work piece. A good rule of thumb is to set your feed the same size as the radius of the tool for rough-out, and just under the radius for the finish. If you get chatter, increase the feed.
Use an indicator to center your work. I have a 3" X 4" piece of brass I use to tap the work piece while it is running and that usually bets it in close enough to work. Remember if you measure 0.001" run out, you are in 0.0005 total OOR, (out of round).
Most 3 jaw chucks don't have the 3 set screws to center your work, so tapping them will get pretty close. With a 4 jaw chuck you have to indicate every piece, but a 4 jaw holds very tight.
I have used several tool post grinders, and they can (or rather the debris from the wheel) can mark up your ways. I used to use wet rags (water) to keep as much as I could from getting in the ways. Use a good way oil, and use extra (to flush) oil when grinding.
I personally have never had an issue with dust hurting the motors. Grinders have the same type of motors, and all they do is grind. Most motors have sealed bearings with the shields, so dust isn't an issue. I am not familiar with the type of lathe you have, but I doubt it has a large HP motor on it, but it can still be very dangerous.
Make sure you center the tooling. Usually just sighting the end while the work is turning, or if the tailstock is indicated in, use it.
I'd be happy to help any way I can. feel free to write.
Smiles,
Bill

There is a good thread on this subject at (Non-TEFC motors, Metal & Wood dust?). Essentially metal grinder dust can, over time, cause shorting in open motors and additionally cause brush/commutator wear in universal or dc motors. On the other hand, wood dust will clog and eventually overheat (but not likely short out) open motors and can even clog the external fan housing of TEFC motors.

I don't have a tool post grinder, but suppose that those hobby machinists who do - have a lathe with a totally enclosed motor and sealed bearings.

Journal bearing-equipped machinery like my first Shop Smith woodworking machine (circa 1950) are also susceptible to airborne metal or ceramic dust - I stupidly jammed up the bearings cutting ceramic tile with a dry diamond blade many years ago and had to rebuild it. I didn't have a wet tile grinder at the time, but do now.

After this experience (now being gun shy) I moved my old Sears dry grinder into my garage workshop, away from my metal working shop in my house basement and purchased a Tormek wet grinder for drill, cutting bit and woodworking tool sharpening.

Gary (kngtek)
Calgary, AB

Thanks for that, Gary. It's about what I expected but, lacking experience, didn't want to volunteer, hence the question.

I might point out here that the OP was talking about a 7 x 14 mini lathe. I expect that such a lathe and many of similar size will lack TEFC motors, hence my concern about grinding on such machines. OTOH, from what I've read, the motors will probably long outlast the electronic speed controls on these built-to-price imports even if used exclusively for grinding.

Thanks for bringing that to our attention, I should have mentioned not to use just a single layer. I like rags for the top layer because grinding swarf does not bounce off, like it does on a smooth or hard surface. The rags provide a labyrinth to trap particles,and the oil is sticky, oil can not be used where sparks are generated, you don't want to start a fire. Unless the motor is totally enclosed, fan cooled, (TEFC), it must be protected, always including the shaft so nothing gets past the seals or into the bearings.