I can appreciate that, but for the newbie evaluating a garage-sale machine, there's no way to tell if that bronze bearing has been run dry and galled, with some STP to smooth it out for the sale. Yes, you can do that with a roller-bearings spindle, but if it's bad, you can buy bearings and change them out.
Well, I don't usually do heavy stock removal on big projects. Maybe I'm ruined for life by starting out on an Atlas 10" with blitzed babbit bearings. After taking a cut with a radiused cutter making a 1/8" wide chip and having the lathe dance acros the floor with a noise that could have been heard literally a block away, you get timid!
And, maybe, with time, I'll learn to take more advantage of the capabilities of this lathe. Much of the stuff I do is cutting down small spacers, threading little adaptors and such. I looked for a long time for a larger lathe that had higher speeds and a good spindle bore, so it could do everything on one machine.
And, I AIN'T complaining. But, if I had known at the beginning it was going to take 22 months on an off, I would have found a different way to do it. But, once I started, I pretty much had to finish.
I have a lot of positive-rake tooling that I got comfortable with on the Atlas. I will have to try out some neg rake tooling some time.
Jon
.250" on the diameter, it is an 8 TPI screw, so .125" actual feed! But, I rarely look at the dial, as the machine came with a Mitutoyo DRO. I took the scales apart, and was glad I did, they had a LOT of crud in them, but it hadn't done any damage yet. Anyway, I haven't had too much chance to do precision bearing fits with the toolpost grinder since I got the Sheldon running, but I'm sure it will be a lot less tense to make precise interference fits than on the Atlas. I did some shaft couplings in the last couple weeks and some of them came out with air-bearing class of fits over the full length, so it is really working great.
Everything on this machine is "to die for", except maybe moving it. The carriage feed handle has a bit of a heavy feel to it, maybe the Moglice on the carriage slide has too much area or something, or maybe I'm using too heavy an oil since it now has the Moglice. Sometimes that is a slight annoyance, but the handle is huge, and despite a fair bit of drag, you can still move it quite precisely. I was really worried I wouldn't get the carriage properly aligned when it all went back together, but it really came out as dead on as I could possibly measure.
About the only drawback to owning a tool like this is I'm afraid to let my kids touch it! They couldn't get into too much trouble with an Atlas, but this thing could KILL! Also, I wouldn't want to risk them having a major crash and seriously wrecking it.
Jon
Crummy ones, but yes :
Negative rake is the key to moving material. Unless you get involved with some very strange, large chip breakers in carbide, positive rake usually won't come close to taking a cut like I described, and even then you'll suffer a short tool life. Roughing with positive rake is generally an invitation to failure---in general due to chips damaging the cutting edge. That's almost non-existent in negative rake.
If you haven't experienced negative rake tooling, the next time you have some material to remove, give it some thought. Be certain that you match the grade of carbide to the job at hand. That can be a serious issue when you put the tool to work.
Harold
That's really the best of all worlds! I would be inclined to ditch the DRO-----but that's me. I see no need, and can do .0002" work on a lathe, as long as the lathe is willing. Sounds like yours is.
As long as you can position the carriage as required, that can be a good feature. I've run a lathe that was too loose, and caused a drunken thread by the carriage handle traversing across center at the apex of the curve. I should have known better, but I'd never experienced anything like it. It was a great way to learn a lesson, however. The returned part, a coarse Acme threaded shaft for the aero-space industry, was embarrassment enough for me to last a lifetime.
That's the price you pay for owning an industrially rated machine. They are, indeed, easy to damage, and can be killers-----that's why machinists aren't found on every corner------and why a guy that has played on a machine in his garage, making a few pounds of chips, shouldn't see himself as a machinist. Those of us that have worked in the trade have spent a lot of time learning to operate the machines in a safe and sane manner, with the hopes of turning out good work in the process. None of that comes easily, nor does quality *and speed* come without considerable experience.
Judging from what I've seen and read, you made some good choices, landing on your feet. Said another way, you did good.
Harold
I remember those - what a trip at the time. I own a Sheldon 11x44. Nice lathe - Dad and I bought it together in a Hardware store and had it delivered. The tools..... we put into the car. Thank goodness for the new fangled RED Station Wagon !!! wow color. And what is this storage area for - fold down bench seat... Storage for tools!
Maritn Mart> Wes wrote:
According to :
[ ... ]
You mean "this newsgroup"? "Site" refers to a web site, where there is a single system which hosts it -- or perhaps one or two backup system as well.
A usenet newsgroup, however, (you may *think* that you posted to a "Googlegroup", but you posted *through* Google's web-based interface t a usenet newsgroup) is hosted on thousands of news servers around the world -- and while Google gives you access to it, it is far from the best way to access it. :-)
Will *all* be aluminum, or will you be making these in other materials as well?
It can usually -- check the travel of your compound to make sure, since I don't have access to a Logan of that size to check (and
1.6" sounds a bit long for that) -- but that is a reasonable way to go only for a few at a time. It is a lot of cranking and your hand will get tired quickly.So -- if you can find a taper attachment, it will significantly improve your productivity.
Also -- look for a collet closer system for your machine. Lever style would be nicer, but you probably will only find a handwheel one. The collets to fit this machine will probably be 3C collets, not the larger 5C ones which my Clausing uses. But -- they should be adequate for stock up to 1/2" diameter at least. With this, you could feed long stock through the headstock to make a part, part it off (cut it off), advance the stock after loosening the collet, and make another just as the previous was made. You'll want some kind of guide to keep long stock sticking out the headstock from starting to whip. PVC pipe in a support will do quite well for this. If it *does* start to whip, it can be quite dangerous.
I gather that both the OD and the ID will have the same 5 degree taper. The ID could be done with a custom reamer (or maybe a standard reamer, such as for taper pins might be the right taper -- you will need to check on this). You could drill the hole, and turn the taper with a boring bar in the toolpost and using the taper attachment, and then switch to an external cutting tool to cut the taper towards the headstock prior to parting off. This has the advantage that both operations could be performed with the same setting on the taper attachment.
Do you need to then make a blunt cone on the small end of the ferrule, or will it be cut square across?
If you make the OD taper first, and then part off before making the ID taper, you will have to come up with some other way to hold the now tapered workpiece prior to cutting the internal taper. (I would use a chuck with two-piece jaws and mount soft jaws on the master ones and turn the taper in the jaws to hold the tapered workpiece.)
Welcome, and good luck, DoN.
I can't imagine the lathe in question couldn't deal with your project, assuming you don't expect high volume production from the machine. It's not designed for that purpose, and would not be well suited for that application.
You didn't make mention of the diameter of the hole, which can be important, and probably is.
Using the compound rest for such a taper isn't reasonable if the smallest diameter is quite small, for you'll have considerable trouble with tool clearance and tool rigidity when boring, perhaps making the job difficult, of not impossible. That would be particularly true if you're new to machining and don't understand the tricks of the trade, and understand cutter geometry such that you can grind appropriate boring tools.
May I suggest to you that you explore a tapered reamer for your application? I'm not normally a reamer fan, but there are applications where they excel, and this could be one of them. You'll get uniform results hole to hole, assuming you hold a constant depth, and it would be much faster than boring. Depending on your particular setup, could be the finish would be superior as well, although that may not be the case in practice.
You mentioned steel. If the entire end is made of one piece, perhaps leaded steel would not be a great choice (12L14), but it would be a great choice for machining, assuming it develops the physical characteristics necessary for your application. It would not be an acceptable choice if there is any welding involved with the tips you'd make. It machines exceedingly well, and will yield better tool life and surface finishes than mild steel or alloyed steel. I know nothing about arrows, so if my comments make no sense, I apologize.
Harold
...
Also, it can be difficult to keep a consistent feed (you need to crank the handle at a consistent speed). When I used the compound to turn a taper, I took off the compound crank handle and chucked the shaft with my cordless drill. Much faster, less tiring, and more consistent than hand cranking.
Bob
Hey Bill,
Hmm....Don't know why nobody else said it, but......
Well, Welcome to RCM !!!
I see other's have thrown you some advice, and I think you will get lots of use of the Logan for your hobby(??). There is a guy here that does pool cues with one.
And I don't know, but..... wmhinkley ... sure rings a bell. Wonder why? You on any other newsgroups or lists? Michigan? SW Ontario? N.A.M.E.S.? Something........???
Take care.
Brian Lawson, Bothwell, Ontario.
I am a HSM and I wouldn't be without my 11 inch Logan. Not as pretty as a Monarch or hardinge, but I have been amazed at the uses I have put mine to. Never expected to use it as much as I needed to. Parts are available, too. Mine was pretty old when I got it, but the spindle bearings are good and I can hold good tolerances(1 or 2 thou)if I don't hurry the job. Only problem I have had with it is the clutch sometimes gets finicky and doesn't pull in all the time.
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