So I recently got myself a used matal lathe. It came with a pretty good selection of accessories, but I am looking to fill what I don't have that I may need.
First, I have almost no experience, so I have been studying. I have several books including MH and "Machine Shop Practice." To firm this stuff in my brain, I ordered the 5-DVD set from
"Lathe Learnin'" made by Precision Measurement in San Antonio. Good Stuff. I learned a lot that willl save me much wasted time.
In two sections near the end, he uses a faceplate that, rather than being on the lathe spindle has its own spindle that is then clamped in the lathe chuck. At one point the spindle has a point as it is used to drive a dog for taper turning. Later, what appears to be the same faceplate, is used to set up a piece clamped off of the lathe for drilling and boring. I couldn't tell, but it seems that the center point would be in the way for this operation. No mention was made either time about the face plate and spindle itself.
So -- this seems useful -- the question: Are others doing this? Can I easily buy a faceplate/spindle that I can clamp in my chuck. With/without a center point? If so what do I look for and where to find it.
A faceplate held in the lathe chuck would be marginally useful IMO.
You can in general get *anything* for any normal lathe, whether it has a threaded spindle nose, a D-n spindle nose, or an L-n spindle nose. Just look on ebay.
Lathe dogs are excellent to buy imported. They are low precision items.
Buy a copy of "How To Run A Lathe" by the South Bend Lathe Works. Read it several times. That book is a gem. Any edition is fine. Lindsay reprints it but there are bazillions floating around used. I bet I own 4 of 'em.
Its advantage is that you can move a project between the lathe, milling machine, and drill press. But, you can do the same with an adaptor machined to duplicate the lathe spindle nose on a rotary table on the milling machine or clamped to the drill press.
And -- if you can't easily find a faceplate for your lathe's spindle, you could use it there -- with the disadvantage that the faceplate may be more off center (in a 3-jaw chuck), or may require tweaking (in a 4-jaw chuck), -- *plus* -- that moving the faceplate a greater distance from the spindle nose increases the likelihood of chatter.
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Neither did I. I didn't because different sets of lathe dogs need different numbers to cover a given range. So -- start out with
*whose* lathe dog sets -- and the answer will be in front of you in their catalog.
If you buy them used from eBay auctions, you will likely get them one or two at a time. Beware that the tails of some may be too thick to fit the slot of the dog driving plate for your lathe, so you may have to grind down the thickness of the tail, or widen the slot.
Fork-tail dogs or straight-tail dogs are used with plain faceplates, where a screw is fed through one of the slots in the faceplate, and secured to the tail of the dog (if a straight tail dog), or passed between the tails (with a fork-tail dog).
There are all kinds of designs. Straight-tail, bent-tail, forked-tail. The older ones have a longer square-headed screw, which has been superseeded by shorter slotted headless screws, because the square heads are more likely to catch in a sleeve, and pull you into the running machine. The slotted headless screws are shorter, so they cover a smaller range, needing more to cover the whole of your range.
There are also bar-type dogs, which consist of two parallel bars, joined by two square-headed screws, and a bent tail from one of the two bars. One of the two bars will have a 'v' at the center, and this will cover a much larger range (given long enough screws. But it is normally used on a dividing head for turning a mandrel for something like slotting the teeth in a gear.
To go with that, I've seen centers which had a T-bar at the pointed end, with slots in the ends to steady the tail of such a dog as in the paragraph above. The slots each had a screw to clamp the tail into a fixed position. (Sometimes, lathe dogs were tied in place with wet rawhide, which would then shrink as it dried, holding the workpiece firmly against chatter.)
I've seen ones which were obviously made for a single diameter workpiece, with two U-shaped slots on the ends for screws to attach it to the faceplate. Those have a very short setscrew.
So -- I hope that you at least now understand why you aren't getting a fixed number for the size range which you specified.
Mounting a face plate on a spindle in the chuck is, for the beginner, a questionable procedure. The whole idea of turning between centres is accuracy. Lathe chucks tend to have less than optimal accuracy when requiring tight tolerances. Also, by moving the "centre" or point as you referred to it, farther from the bearings in the head, you tend to decrease rigidity in your setup. By using a spindle mounted faceplate and a soft point MT5 (if that is what your spindle is) centre to do you "between centres turning" you will have a setup on which you will be able to produce the most accurate work your lathe is capable of producing. Buy the largest faceplate your lathe can swing, and a small dog drive with a couple of drive dogs.
I have a document for a similar lathe, but I see that it doesn't match mine exactly. One option in those pages shows MT 5 for the spindle. My measurements seem to agree with MT 5 pretty close, so I think it is correct.
To be sure, I guess I should buy an MT 5 center and try it.
I asked because I don't see much need for turning between centers now, and popping in something to the existing chuck would save time.
Maybe a bit of sacrifice in accuracy, but it could work for me.
Looked good in the video. He did several things that broke the rules, like turning threads without using the compound feed.
No, don't do that. There are spindle adapters that permit the use of smaller centers, which should be your objective. Look for a #5/#3 adapter, and use a #3 center, or one the same size as the tailstock center, if it's different.
Well and good, but is that in your best interest? Wouldn't you prefer to learn things that are useful instead of things that may not be?
I worked as a machinist for 26 years of my life, including running my own business for 16 of those years, and never encountered any such a setup. Frankly, I wouldn't be too interested in one, either. If for no other reason, on small machines, the more you add to length, the greater are your machining problems. There are other methods to improve holding capabilities, most of which would be more useful. Soft jaws is a good place to start your learning curve, but reserve that for the time when you better understand cutting tools and how to apply them. At this point, you're worrying about things that may never be an issue when you are more familiar with machining techniques.
Regards holding objects between centers, it's easy enough to chuck a short length of stock and turn a 60 degree center if you'd like to avoid buying a headstock center, which you'll find gets very little (if any) use when you get better at machining. Working between centers is precise, but a complete PITA as compared to holding your work by other methods (speaking of soft jaws).
We have no idea what you do for a living, but if you think you can master machining in a few days, you're likely to be very unhappy. It takes most guys that work in the trade several months to become even remotely competent, assuming they're doing work of any quality. Anyone can make chips, but it takes skill, talent and considerable experience for one to make parts per print, reliably, and with reasonable speed. You'll come to respect the talent of others as you struggle with what you may think are simple procedures.
You're right about the more you have to learn. Few, if any, machinists that have worked in the trade for a lifetime are well rounded enough to be comfortable in all machining processes. There's just too much to know to learn it all. You could easily spend a lifetime on gear cutting alone. Don't let that bother you-----simply learn to do the things that are important to you.
I thought I should mention that I sent an email to the DVD author and got a reply. He says the faceplate came from a small Atlas lathe and he turned his own spindle that screwed into that faceplate.
Just wanted to let everone know what I learned. I still think it could be useful for easy set-up on occasional work that needs a faceplate, but I have no real need for it now, so if I try to make something like this it will be much later.