More Machining Mysteries

January 19th, 2012

Even Solomon Couldn’t Sift Through This BS

I’m going to get rid of my annoying Clausing lathe. I was a moron to try to save pennies by buying an old lathe with no features. I want something that has a 2″ bore or bigger, and I want metric threads on tap (pun possibly intended) instead of having to perform major surgery on the lathe.

Every time I start to think I know a little bit about what I should buy, I hear a conflicting story.

When I was looking for my first lathe, I was told I had to buy “old iron.” American machine tools RULED, even when they were 300 years old and wouldn’t turn on! They were so BITCHIN’ compared to CHINESE JUNK, only a FOOL would buy anything else!

Then I bought my geriatric lathe, and I started hearing stuff like this:

It’s a cruel trick to witlessly seduce a noob into buying what was once a great machine tool that today is worn-out with broken and missing parts. For a year the poor sap will break his heart trying to get acceptable quality work from a machine that would challenge a machinist of 40 years experience. Then thoroughly dicouraged and thousands of dollars poorer he junks the lot and takes up a lesser vocation.

When a noob asks you a question and you respond from basis of experience you are undertaking a responsibility. I strongly suggest those of you with experience AND strong opinions, set aside your personal preferences and guide your protege into choices he can live with.

PM is a bit zealous on the old iron topic and many there recklessly propagandize the poor noob into believing the old worn-out American junk is superior to new, snug better quality Asian import machines. I delight in scotching their prejudices with personal experience, matching machine to task scenarios, and actual quantified data when appropiate. Tragic to say the noob has been misled in ALL machine shop message boards.

That comes from a guy named Forrest Addy, who is openly worshiped by machining-forum nerds. “PM” means the Practical Machinist forum.

Og said to go ahead and buy Chinese, but I thought the “old iron” people had a clue, so I wasted my money on the Clausing.

I’ve been looking around to see what’s available, and I’ve been thinking the Grizzly 16″ gunsmithing lathe might be a good move. It’s very cheap for this type of lathe, because it’s Chinese, but it’s hyped as having a bunch of special touches, and it looks like the hype has some ground under it. I spoke with a Grizzly tech, and he said the claims are true. It really does have special bearings and gears. It runs exceptionally smoothly. It’s a decent machine.

Shiraz Balolia, the president of Grizzly is a world-class marksman, and he had this lathe created because of his interest in gunsmithing. That’s actually true; it’s not just catalog puffery. It may look like other Chinese lathes, and it may be built in the same plant, but it has improved parts and tolerances. I find that credible, simply because I know how it is to get caught up in a fun project related to a hobby. Also, Balolia chose this lathe for his own use and kept it for a few years. As he has pointed out, he can have any lathe he wants. And you can download the specs and sample measurements from Grizzly.

While I was researching this, a very experienced machinist suggested a different lathe. It costs $2950, which is extremely low for an American 16″ lathe, and it has a sliding gap, which is the only kind of gap which can be used without messing up the lathe. Removable gaps can’t be reinserted accurately without major work or extraordinary luck. Funny how lathe makers don’t mention that in their ads. I found that out this week, so I no longer care whether I get a gap.

Here is the lathe he suggested:

That’s an ancient 16″ Leblond with a sliding gap. There are other photos. The ways are rusted. The compound is rusted even worse. There is so much rust on one of the screws, the surface appears to be eroded by maybe 1/16″. It has clearly been sitting in the rain for a good long time. But this machinist, who is respected by people I respect, said he would buy it sight unseen.

You can see why I’m puzzled. It looks like scrap iron to me. Does the motor run? Is the saddle frozen to the ways? Does it have .125″ of way wear near the spindle? Who knows? I wouldn’t go near it. But if a really good machinist says he’d buy it, who am I to discount his opinion?

I’m not going to buy a piece of junk like that. No way. But you can see how it would be hard to make it fit into my understanding of machine tools. And it makes you wonder: if something that abused and worn can be considered a good buy, what does a REAL junker look like?

I’m learning more about the machining itself. It’s pretty irritating, but it’s better than living in ignorance. Here’s an example.

There are lots of DVD teachers out there, and they give the following procedure for chucking round things in 4-jaw chucks. Stick the work in the chuck. Tighten it. Put an indicator on the part. Turn the part by hand and adjust the jaws one at a time until the runout goes away.

The old guy who suggested the Leblond says that’s wrong. If you do that, it will be okay where the indicator touches it, but farther out, it will be out of whack. So you have to wrap the base of the part in a soft sheet of metal, like copper, and…I don’t really understand this…chuck the sheet and part (chuck jaws touching sheet) and bang around on it until you get perfect alignment all the way down.

I’ve seen lots of people talk about 4-jaw chucks, and this was news to me.

I’ve also learned that you can tram a lathe using a precision angle block. This is just a precisely ground hunk of metal with two perpendicular sides. You put it on the table, put the extended quill against it, and adjust one axis until there is no light between the quill and angle block. Then you do the other side. Takes two minutes. Do this, and you’re accurate to within half a thousandth over six inches. You may want better accuracy for fly-cutting, but for 95% of what you do, this will cut the mustard, and it gives you the freedom to move your mill’s head whenever you feel like it.

The blocks are cheap on Ebay. I found a new one for $60, delivered. This should be a great help, and I can also use it on my table saw, drill press, and band saw.

I’m learning that you can always make machining easier or harder than it already is. There is no end to this stuff.

Yesterday I tried to open up the opening of the follow rest I’m making. I had a tough time trying to find a way to clamp it. I couldn’t get it to fit in the vise with the V-blocks needed to hold it at a 45° angle, so I decided to try clamping it to the table, using parallels as spacers. This is as far as I got.

I finally realized I was reinventing the wheel in order to avoid lifting my 10″ rotary table from the floor to the mill. I decided to face the risk of an episode of incontinence, and I picked the 120-lb. table up and stuck it where it needed to go. Then I learned that my clamping stuff won’t work with it. The T-slots are narrower than my mill’s slots. So I had to get a whole new clamping kit, plus several additional T-nuts. That’s on the way from Grizzly. Also ordered some lathe dogs, finally. I don’t know why some lathe dogs cost $40 and others cost $3. They seem fairly primitive. I ordered the $3 kind, so I guess I’ll learn the answer.

I realized I needed a THIRD rotary table. The tiny 4″ one won’t hold a big part, and I really don’t want to lift the big one more often than I have to. I figured 6″ would do. I checked Ebay and the other sources. Used ones are getting hard to find. I was surprised. And Asian prices are creeping up. I’m glad I bought my other tables a long time ago.

Enco has an insane pricing structure. I checked 6″ tables, and it turned out 8″ tables were considerably cheaper, so I did what I had to do. Same company. Same quality. Go figure. This happens a lot at Enco.

I keep checking lathe prices. I don’t know if I’ll go with Grizzly, but whatever I do, I’ll know a whole lot more about lathes than I did last year.

I still think you have to be an idiot to buy old American machinery that isn’t like new. Last night I realized it perverts the whole business. You buy machine tools so you can make things from metal, but then you find you spend all your time wet-nursing a senile machine that deserves to go to its final reward. Machine repair is not machining. Two different things. You can buy a car from the junkyard and make it run, but most people just want to drive, right? Same idea.

I guess if you have 40 years of machining behind you, you can make any machine work. I don’t really know. I don’t know how you can take a lathe with .005″ of wear by the chuck and flat ways 10″ away and make a straight part 15″ long. It must be magic. I can’t do it.

Don’t buy a worn-out machine unless you or some helpful buddy who lives under a mile away is a complete machining wizard. That’s probably the bottom line.

I thank God for letting me do all this incredibly cool stuff. It amazes me that I get to do so many things I’ve dreamed of.

9 Responses to “More Machining Mysteries”

  1. og Says:

    Properly constructed gap bed lathes have taper pins that allow you to properly and accurately relocate the gap insert. We’ve had the one in and out of the Nardini a dozen times, and it’s fine.

    As for the tables, you need a Ruger hoist.

    http://www.rugerindustries.com/

    You can make one easily enough out of a cheap engine hoist and some scrap iron. The difference between this and a regular engine hoist is the counterweight in the back instead of the “Arms” in front.

    A scissor lift table is probably nearly as useful, and may even be less dangerous to use.

    http://www.google.com/products/catalog?q=lift+table&hl=en&gbv=2&rlz=1R2DMUS_enUS353&gs_upl=1219l3797l0l3969l11l10l0l2l2l0l328l1843l0.2.5.1l8l0&um=1&ie=UTF-8&tbm=shop&cid=16978041117563782903#

    A Jet one like this is about the single most useful piece of equipment a home shop can have.

  2. Steve H. Says:

    I wonder if that’s because Nardini is a higher-end lathe. The Grizzly manual says it’s “nearly impossible” to put a gap back in their lathe without losing precision. They actually use that phrase.
    .
    A scissor table or hoist would be great, but I have to place conservation of space above sparing myself effort. If I could just find a convenient spot over 3 feet off the ground, I’d be okay. I don’t have any trouble lifting the rotary table, but it makes me nervous. It’s more than heavy enough to cause an injury if I make a mistake. Starting with the rotary table on the ground makes it much more likely that I’ll have a problem.

  3. Onmilo Says:

    Grizzly offers some very good products at very reasonable prices.
    Just having the ways scraped on that rust box lathe will cost an easy $1000

  4. Steve H. Says:

    Wouldn’t they have to be ground, since they’re hardened? I wouldn’t even be able to guess how you’d set a 60″ lathe bed up for grinding. I’m pretty sure there is no such thing as a surface grinder you can park a giant lathe on and push a button.

  5. og Says:

    “I’m pretty sure there is no such thing as a surface grinder you can park a giant lathe on and push a button.”

    You need to come to IMTS this september.

    That grinder is called a mother machine, a machine that makes other machines. I’ve seen them 16 meters long and three wide. They usually don’t bring those to IMTS but sometimes they do.

    And yes, it would be ground and also probably scraped or flaked.

    If the Grizz isn’t pinned in place you can always add pins. tapered pull dowels and tapered reamers are cheap.

  6. Steve H. Says:

    The “push a button” part was what I was hanging my comment on. The closest one of these things to me is probably in Ohio, and I’ll bet you have to totally dismantle the lathe and do all sorts of weird setting up on the grinder.
    .
    I didn’t know you could scrape hardened steel. For that matter, I wonder how deep the hardening goes.
    .
    Doesn’t matter. I wouldn’t take this lathe if it was free and came with a coupon for a cruise.

  7. Onmilo Says:

    Most especially don’t accept the free cruise coupon if the Captain hails from Italy, just sayin’,,,,

  8. Steve H. Says:

    My current target is new Grizzly or works-as-new Japanese, Korean, or Taiwanese. The cost of a G0509G MIGHT get me a very nice Whacheon, Webb, Kingston, Mori Seiki, or Namseon.
    .
    I have to give the folks at Eisen Machinery credit, though. They sell good new Taiwan machines so cheap, they’re very tempting. Unfortunately, “cheap” means $14,000.

  9. tom Says:

    Get the Grizzly, good support for parts and that help with problems.