FAQ - What about a lathe?

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Richard Hull
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FAQ - What about a lathe?

Post by Richard Hull » Sun Jul 23, 2017 3:54 am

The average fusioneer may not need a lathe. Some few arrive here owning one already. For those contemplating owning one now or in the future, this FAQ may be of some help.

When choosing a lathe the question comes back to what is the largest item you might wish to turn in future? How much are you are willing to invest? More questions....Will you be working on a lot of long items on the lathe? What about big diameter stuff? All of this determines the bed length and chuck size of the lathe you will have to purchase.

I have acquired my lathes both new and used. I will ultimately attach images here of the lathes I have and use.

99.5% of all of my lathe work is right at the headstock, (chuck). This is when you are turning an item under 2 or 3 inches long which does not require the use of a tail stock. I almost never turn a 12" long item. Thus, for me, a lathe with a 14" bed is overkill. I just seem to never work between centers! (use a tail stock) Yet, due to lucky buys I have 2 lathes with 24 inch beds. What is more important to me and my work is a really good chuck and an over bed clearance to the center line of at least 6" for doing larger items. Even this is not needed for 90% of my work. This is why I have 4 lathes in the lab.

As noted above.....What will you want to do with your lathe in future??

A new lathe, a small one, even from China that is worth having will be about $500+. Grizzly has many good lathes with metal gears and a new one from them will start at $1000+ and go up fast.

A used lathe can be a fanastic bargain or one of the worst decisions of your life. I purchased a classic K9 South Bend lathe (the best of the best) made in the late 40's for $200 I knew what I was getting, too. The three jaw chuck was totally shot. The bed ways and cross slide were all in good order. The large 4 jaw independent chuck was rusty but, otherwise, like new.
Four jaw independents are used on a basis of 1 job with it to 250 jobs with a 3 jaw. This ancient lathe uses a 1-inch wide flat, tensioned belt on stepped, domed pullies so it could be driven in an old factory from overhead drive spindle pulleys. Such lathes were commonly found 20 in-a-row driven from the ceiling on one long shaft powered by a single multi-horse motor.

Luckily, South Bend has an industry standard spindle chuck thread and I purchased a new, fabulous 6" diameter, 3 jaw chuck from Grizzly that screwed right onto the old Southbend for $250.00. This lathe is now used for all of my "big" work and when I am cutting screw threads. This is the only lathe I have with a 4 jaw independant chuck which is a must have for eccentric machining or chucking of square or odd shaped pieces for machining. 4 jaws are a nightmare to work with and I would rather take a beating than have to use one, but they can be lifesavers and are often the only way to get a specific complex job done with any degree of precision.

I would say that 95% of my work is under 2" long and under 2" in diameter. This is mainly where I need to do a smooth cutoff or just "skin" a part down to a precise diameter, bore a precision hole or internally thread a short item. Really, most of my work is under 1-inch in diameter. The largest diameter I have ever worked is about 4-inches and the longest about 10-inches.

I just don't do big stuff.

You must know what your material limits are and what you are planning on doing in future or you will over spend on a big machine, whose capabilities you will never use or live to regret you didn't buy a bigger lathe as larger work comes along.

All lathes come with a standard 3 jaw chuck. As I do a lot of close in to the chuck turning, with no tail stock supporting the work, large diameter, short pieces can very rarely flip out of a wide open 3 jaw!! Dangerous if not deadly to see a big piece of spinning metal come at you or dance around nervously behind the lathe or hit a wall. Thus, I prefer to use only a 6 jaw chuck for big un-supported work close to the head stock. Never had one flip out on me in a 6 jaw! This is charged to lathe operational safety. The novice might want to tailstock support big diameters in their 3 jaw chucks, even if only 3" long.

Many of my hobbies from model railroading to fusion work just needs lathe work on smallish items. I have a "Micro-Lathe II" made for "pin work" 1/4" diameter and smaller. My largest can work all the way up to machining short 4" diameter pipe sections (South Bend).

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My Lathes.......

1. K9 South Bend.... Big work and odd ball screw cutting 3-jaw and 4-jaw chucks. Metal change gears for threading. Belt speed selection
2. Kennedy combination lathe (Grizzly) giant 9-inch over center swing (18" diameter) with a 6-inch, 6-jaw chuck....Larger materials and large diameter disk skinning. Belt speed selection. All metal change gears for threading. A sharp eye will notice, in the photo below,
that this is a combo lathe, drill press and milling machine!!! You might do well to by this Grizzly item as it might serve all your needs in one purchase. I have a very large milling machine and two large drill presses, already. So the head with this extra on it is merely swung out of the way in the photo and has never been used by me. I purchased this lathe solely for its monsterous over bed swing. It was on sale for $999 in the year 1998.
3. Micro-Lathe II.....Pin work...It can't chuck over 1/2" diameter pieces. Model Railroading, tiny work and for easy cutting metals. Belt speed selection. can't be used for screw cutting as the work is always so small that common taps and dies are the choice for threading here. I have taps and dies from SAE 00-80 up to 3/4 inch, including metrics.
4. Harbor Freight Chi-Com lathe..... 3-inch, three Jaw chuck. 12" bed, only 6" of which is usable with tail stock. I have permanently removed the tail stock which tends to get in the way. (see photo) 1.2 inches is the largest diameter it will support. Vastly variable electronic speed control. (nice!) ....Metal drive gears, but plastic change gears for screw cutting pitch. I haven't used this lathe for screw cutting yet. Only one complaint...The large black traveler knob is too close to the chromed cross slide handle. They do not go afoul of or jam into each other, of course, but hand clearance between them is less than I am used to. But, hey, it is a small lathe and the chinese are small people. Hamfisted Americans may have issues.

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I bought the harbor freight lathe when it was $495.00, a couple of years ago. It is now $569.00. I used a Sunday only, holiday, 25% off coupon, and paid a bit under $400.00 after taxes.
A really sweet little lathe for smaller work.

Which lathe sees the most action? The little Harbor Frieght lathe. Why? It is the perfect size and I can set the speed precisely to secure the fastest cuts with the least tool wear without farting around with belts and gears. As noted, this little lathe works extremely well with easy, free cutting metals, Aluminum, Brass, Bronze, Zinc castings, etc.
Next would be the Kennedy mostly due to its fabulous 6 jaw, self-centering chuck. Grizzly said it couldn't be done, but I mounted their big, heaavy, 6-jaw chuck on my own custom made face plate! I made the face plate on the South Bend! (Using tools to make tools)

Next, the South Bend. It is great for big, longer items and threading. I turn a lot of pipe fixtures on this big boy.

I rarely use the pin lathe except for really fine and tiny work. (Although the harbor freight lathe has taken a lot of work away from the micro lathe.)

If you buy a used lathe to save money, try to purchase it from a machinist. They know their stuff and have probably maintained it well, although like my K9 southbend, it might look rough. Older lathes of high quality are to be recommended as the price is usually right. Just make sure the bed and ways are in good order and the traveler and cross slide are in good condition. A good, used lathe should come with a set of change gears and a metal plate table permanently rivited on the side cover, giving data on the gearing set up for screw cutting.

This is my experience of 40 years with lathes. I am not a top level machinist by most any standard, though I do machine stuff often. I am 100% self-taught by first reading and then doing for 40 years. The hands-on imperative at work.

Richard Hull
Attachments
micro-Lathe.JPG
Yes it is small but is great for tiny work on easy cutting metals. A great hobby lathe.
South Bend.JPG
Ugly, old, well used, but still a winner with its new 6" chuck. South Bend = Quality!
Harbor Freight.JPG
The Harbor Freight lathe, My most often used lathe. I love it.
6 Jaw Kennedy.JPG
The nice lathe with largest over bed swing and a beefy 6 Jaw chuck which I added, later. (Grizzly)
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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