Is this lathe worth buying for constructing small engines.

[Jasonb]

Ply screwed to the back and both sides will do a lot to firm up what you have.

You need to get it to red heat to be able to harden it which is about 800deg c but it will burn you long before that.

Hardening does make the metal brittle that is why you mostly temper it after hardening.

[gipetto]

plywood is or was at least really expensive. I'm thinking i should go for a tripod table design, as that would be more stable than a 4 leg. I figure that it should be composed of triangles for stiffness, so each leg would have a strut at its foot that goes over to the base of the neighbouring leg. the struts can be welded to each other where they cross.
that leaves the problem of how to fit a rectangular table on top of the triangular base, maybe an angle iron or box frame around the perimeter of the rectangle, and more struts from the foot up to the frame.

[gipetto]

I was inspecting the 4 jaw chuck and it turns out the 3 jaw chuck key does not fit it, despite being an oem part. (sighs)
also can someone explain why optimum sent an mt3 arbor and mt2, despite everything on the lathe being mt2. what is it for, i checked the lathe pdf, it's meant to be there.

[internal_fire]

optimum sent an mt3 arbor and mt2

It is typical that the taper in the headstock spindle is larger than the tailstock taper. Have you checked to see if the mt3 fits in the spindle?

Gene

[Jasonb]

The manual I linked to the other day says the spindle is MT3

Quite common that a 4-jaw of a similar diameter needs a smaller key than a 3-jaw. Usually the key is supplied with the chuck so check the box.

[ShopShoe]

You definitely want a table that doesn't wobble.

If you use wood, use wood sturdier than you might for just a table. I have used 4x4s for legs and top of laminated "two-by" boards. I use shiplap or tongue and groove joints on the sides of the boards and use long threaded rods through the cross-dimension to hold the top together. I also have used plywood or particle board, but doubled or tripled and glued together.

Steel is also good. I like legs made from square tubing and cross members of angle or channel. I suggest bolting rather than welding as it allows for modification later and avoids distrotion that might happen during welding. (Be sure your stock is straight before using it. It is also helpful to be able to dis-assemble your bench for moving or storing.

You might be able to find a suitable table or stand from a used furniture dealer or junk shoppe. (I have one small table on wheels that came from an office-equipment dealer: Possibly it was a stand for a heavy-duty printer.)

Whatever you do, try to have adjustable feet so you can level the table in its final location.

ShopShoe

[gipetto]

optimum sent an mt3 arbor and mt2

It is typical that the taper in the headstock spindle is larger than the tailstock taper. Have you checked to see if the mt3 fits in the spindle?

Gene

I tried but it rocks, perhaps it only fits securely with the chuck removed, which i have tried to remove and failed, it keeps turning when i fit the wrench to the nuts. perhaps if i make a lever with an axle that i can tighten the chuck on, it will solve that issue.

I should clarify that the mt3 is not an arbor, but an mt3 dead centre. my memory tricks me. I am unfamiliar with the necessity to turn between two centres, surely this would not be practical, due to weak transmission of power? my apologies if i have asked the question about the mt3 part before, i may have forgotten.

The manual I linked to the other day says the spindle is MT3

Quite common that a 4-jaw of a similar diameter needs a smaller key than a 3-jaw. Usually the key is supplied with the chuck so check the box.

I found the key since you mentioned it would be in the box, it was in a recess in the foam. included were a few allen key screws that look quite difficult to install in the chuck. Is it customary to convert these chucks to use studs and nuts instead, like an exhaust manifold would use?

@ShopShoe
I am about 10 miles drive away from a iron metal dealer so it's usually cheaper to construct my own stuff than to buy used. Levelling the lathe would be awkward, I had not considered it since i thought it would be unimportant. is it simply that the level necessary for coolant pumps to operate or is there something else i'm overlooking. I will make do with manual oiling since the work i will be doing is limited. I can of course add some levelling bolts to some or all of the legs.

[Jasonb]

Put the chuck key into one of the sockets in the chuck and hold that with one hand, spanner in the other to undo the nut.

It will rock as your chuck only has a 22mm through hole, the fat end of an MT-3 taper is 23.825mm so it won't go into the taper with the chuck in place

Turning between ctrs is quite common, it is usual to drive the workpiece with a "dog" have a google for lathe dog

No it is just the way your 4-jaw mounts without a separate backplate. Just use the screws and the existing nuts and washers that are holding on the 3-jaw plus hopefully the makers supplied an extra nut and washer.

Just use the "leveling" feet to take out any wobble from an uneven floor. That don't have to be special feet, just drill the box section steel clearance fir some bolts and have nuts top and bottom to lock the position. You could tack weld a nut to the frame if you wanted.

[gipetto]

I mentioned before that i am going for a tripod design though, so even if the surface is not 90degrees to the center of gravity of the planet, it will still be stable, assuming the floorboards also are. levelling screws may be necessary on a 4 legged table but on a 3 legged one?

[MMan]

Hi Gipetto,

If you are comfortable using a welder, steel section makes great workshop furniture. I used 50mm square section and made straight sections that then bolted together to make an L’. As Jason says, levelling feet are easy - a nut welded over a hole and a bolt or foot to the floor works great. In the end it is your choice but strong and stable is what is needed.

The other levelling that may be being mentioned is to ensure that the lathe is not twisted, so not really levelling at all but making sure that headstock and tail are on the same slope. There are various ways to do this - examples can be found on YouTube.

All the best,

Martin

[Jasonb]

Given the long rectangular foot print of most lathes I would say 4 legs would be more stable. When did you last see a dining table with three legs that was not round?

For the tripod assuming two front feet and one middle of the rear, then the two back corners will not be well supported so leaning against the machine may tip it and out of balance work rotating could set up a rocking motion.

[gipetto]

alright then, 4 legs it is.
Another question, suppose i have a thread that i wish to copy but don't know the size. In the frugal past, to check if two bolts have a compatible thread i have intersected the threads of each bolt by holding one over the other in opposite directions. if there's no daylight showing between the threads then i'm usually ok, though there were some occasions when both bolts were compatible but one bolt was clearly of larger diameter.

My set of taps are not large enough to measure some bolts. from what i have read, threads are described by the width of the thread or the turns per inch, which is to say they are the directly related much like frequency and wavelength are related as well as the diameter of the bolt to the top of the thread.

If i were to grab an unidentified bolt and found a tap from my set that intersected perfectly with the threads could i read the turns per inch or the thread pitch described on the tap and using a callipers measure the diameter, and would that give me an accurate reading.
obviously that might not work with taps i do not have such as whitworth, but maybe it could?

[Admiral_dk]

You can get 'Feeler Gauges' that has a different Thread Pitch on each 'Blade'. These are avialable in both Imperial and Metric versions.

Both the above and Taps or Bolts (of known Pitch) can be used as you have found out - though nice to have exactly same 'Shape' (Withwort, Acme and the rest) that isn't important, but confirming that peaks and walleys has the same distances is !

Yet another methode that can be used, is a Vernier Caliber - here you place one 'Leg' @ a peak and the other 'Leg' 11 peaks further away (equals to 10 revolution) and divide the result by 10 to get the Pitch. This isn't as accurate - but should get you into the ball park - or close enough to find the standard Picth it is. Admittedly some Metric and Imperial are so close as to cloud matters a bit - but then the Diameter should point you to the correct one.

Per       

[ShopShoe]

gipetto,

Threads in imperial (US, etc.) are described by the size of the hole or shank of the rod and the number of threads per inch. (For example 1/2 - 20 is one-half inch and twenty threads per inch.)

Metric threads are size and distance from peak to peak of each thread. (For example 6mm x 1mm is 6mm with 1 mm from peak to peak.)

As you are starting out, probably either of those systems will meet most of your needs: Less-often used thread systems may not come up very often and you may be able to create a work-around when they do.

Your appproach of using known-size nuts and bolts as standards is perfectly acceptable for routine work.

As was said by Admiral_Dk above, thread-pitch guages are useful tools to have.

If you REALLY want to know a lot about threads (and other machining concepts) a good reference source is helpful. You can find many online or purchase books. In the USA, "Machinery's Handbook" is the ultimate reference. There are older versions available to consult online for free. I don't have that link handy because I actually have the book. Old versions are useful for most hobbyists because most of us aren't using state-of the art expensive industrial processes to build things to current world standards.

I will also suggest that a good magnifier (or several types) is very helpful in checking things out and in checking the quality of your work.
Mrpete on YouTube has a video on the subject at:

<a href="https://www.youtube.com/watch?v=f7zwFG_uzJA" target="_blank">http://www.youtube.com/watch?v=f7zwFG_uzJA</a>

The magnifiers I like are an optivisor for hands-free use  (Mine takes interchangeable lenses from 1.5X to 4X), a 2X magnifying glass, a desk lamp with ring-light surrounding a 6-inch magnifier of about 2X, and 10X small loupes with high-quality lenses, both with and without built-in lights.)

ShopShoe

[gipetto]

I finished the 4 legged table. it's a massive weight will have trouble getting it up the stairs, would post a picture if i could find my camera fone. i used 2 inch box for the frame and 1 inch box for the stays. the top surface and shelf is 4mm iron. it has nuts welded on the end of each leg to screw in cup bolts for levelling.