Lathe chuck spindle attachment

One of the questions I had was how is the chuck attached to the

Michael

Probably attaches with threads as you mention. Don't buy from this dealer if he does not know or does not find out.

Bob AZ

Many lathe models from China have flanged spindles instead of threaded "noses". With flanged spindle mounts, there are either studs or threaded holes at the back face of the chuck body, and holes around the flange to match the fastening method.

Looking at the closeup pics of the chuck and headstock, shows the flange to be the same size as the chuck.

There may be some common chucks in the 5" diameter range (and possibly a little larger) that can be fitted/machined to adapt to the flange on this BB machine. Chucks much larger than 5" will likely require an adapter plate that the user will need to perform some machining to mate the chuck with the spindle. Oh, I noticed that an adapter plate is shown at the bottom of the description, and separate from the optional 5" 4-jaw chuck.

The machine features/specs show that the spindle bore is 1" and has a MT4 taper. The 1" bore excludes using a 5C collet draw tube.

Collet choices would be Morse tapers used with a drawbar, or adapt the MT4 to 3C collets, and use a draw tube. The 3C collets allow feedthru of material (feeding long stock from the left side), but the workpiece/stock diameter limit is smaller than 5C. Morse taper collets don't allow workpiece/stock passthru. Collets sized MT4 may be relatively expensive. MT3 collets with an adapting MT3/MT4 sleeve would allow cheaper MT3 collets to be used. A few MT4 collets in the larger sizes might be desirable.

There are adapters for MT3 to 3C collets, but I don't know if there are adapters that go directly from MT4 to 3C. The draw tube for the 3C collets may be the same one available for the 9x20 models, or possibly adaptable with (maybe) minor modifications.

Enco makes (or made) a nice lathe with cam-lock chuck, that can fit a 5C snap handle collet setup. If you plan on switching often between lathe chuck and collets, cam-lock is a dream. The lathe you show is definitely not camlock, as you would see 3 add'l square socket ditties, for the cams.

I wonder if 10" is large enough for a 5C collet system..... your 1" bore would not be large enough for 5C.

If it is the same as many of the 3-in-1 machines, it is a standard metric

100mm nosepiece that fits into a recess in the back of the chuck. 4 bolts pass through the flange and are threaded into the chuck.

Bigger pics

Dave

Michael, I would advise against this machine. It really is not big enough, heavy enough and has serious other restrictions, like the number of threads, no taper attachment and perhaps other tooling, which is usually included in a used machine. For pretty much the same size footprint, you should be able to locate a 13 x 40 machine in a tooled condition. You may have to spring for more money upfront, but you will save money over time. I have 3 lathes and all have a taper attachment. I would never be without one., especially if it is your only one. It should be capable of 40 different threads and have a set of change gears for cutting metric threads. Ideally, you should look for D-4 Camlock spindle with an integral MT5 Taper because of spindle through hole size and tooling availability.

You will be tempted to buy others, don't. Be patient, get it right the first time. Steve

useless. One of the questions I had was how is the chuck

further details have not been forthcoming so far.

standard sizes? I am concerned about accessories

Grizzly G0602 which I understand has a 1-3/4 - 8TPI

Good advice, except I don't think taper attachments are so common. My buddy, who goes thru quite a few lathes, hasn't seen a taper attachment in a decade or two.

Are taper attachments wedded to a given lathe, or can they be generic, like a toolpost?

They can be generic, but very unusual. When I bought my 10" SB new from SB in '81, it did not come installed. This is no simple task. In the end, I got it right, but it was truly a pain. If you do not get the taper attachment as factory, you will be faced with a whole series of mods for the carriage, which are not trivial. Secondly, after using the taper attachment on the SB 10 without a differential crossfeed screw and using the SB 13 x 40 SB with a differential crossfeed, there is no comparison. Give me the differential variety any day, as it allows the user to dial in cuts with the crossfeed AND the compound in a conventional manner. Without the differential crossfeed, only the compound can be used as the cross feed is disabled, which is not convenient. Using the taper attachment on my big 18 x 54 Lodge & Shipley is even easier. It is also factory installed.When you need one, there is no substitute. I would not own a lathe without one. Steve

enough and has serious other restrictions, like the

usually included in a used machine. For pretty much

tooled condition. You may have to spring for more

have a taper attachment. I would never be without

threads and have a set of change gears for

an integral MT5 Taper because of spindle through

who goes thru quite a few lathes, hasn't seen a

useless. One of the questions I had was how is the

but any further details have not been forthcoming

there standard sizes? I am concerned about accessories

Grizzly G0602 which I understand has a 1-3/4 - 8TPI

I just thought it might be an option as this guy installed a 5C collet on his G0602 which also has 1" spindle bore:

In any case it was just to illustrate a point. I wondered if the "flange" thing would severely limit me in the choice of attachments. For a start I do not know what quality the chucks offered with this machine are and it would be nice to have the option to go with another manufacturer for replacements. Furthermore, the 4-jaw chuck available for this machine is only 5" which is a bit small. Does this mean one would have to manufacture a whole adapter for a bigger chuck? One has to believe that there are adapters available for this type of spindle commercially somewhere, but without further details how does one go looking for them?

Incidentally their 7X8 lathe also has a flange which I understand is common. LMS sell adapters for *3" flange*. That is the sort of standardization I was looking for. Things would be even simpler for a 9X20 with a 1.5"-8TPI or M39X4mm spindle. Adapters for 3,4,5, or 6" chucks are freely available.

Meanwhile I got a response from the dealer and here it is:

"We do not have exact dimentions of the spindle flange, but it is 5" in diameter and is machined to fit behind the chuck which comes with the lathe. the holes are approximately 3.723" apart. One side of the adaptor is machined in a similar design as the back of the 3 jaw chuck and the other side is machined to accept the 4 jaw chuck. Since you want to use a different chuck we suggest you wait until you acquire the lathe and the chuck then machine the adaptor accordingly. "

I am not sure what to make of it.

Really? I thought a 13X40 would be much longer than 47". They do 12X26 at double the price but that one has issues, too...

You can make a better adapter plate than you can buy because you can fit it as carefully as you want to the exact sizes of the spindle flange and chuck back recess.

If you measured the diameters of the spindle flanges on the production line I suspect you'd see them increase continuously as the tool wore, then jump back to the minimum when it was replaced. An adapter plate to fit them would have to be at the large end of the tolerance in order to fit all lathes, and a sloppy fit on most, while you can make one exactly the right size for yours.

Look at lathe chucks in the MSC catalog and you'll see separate back plates for the common mounting styles. You fit the plate to the spindle, then shape it into a flange that fits snugly into the recess on the back of the chuck.

jsw

Michael, I have done this many years ago and I am passing the lesson on to you. I learned the hard way. Most hobbyists must limit themselves to one lathe for space reasons as well as one milling machine. It is imperative to buy that lathe and that milling machine as capable as possible. Today I have many machines, but that is an unaffordable luxury for most. In my experience of almost 50 years, the size I use for 90%+ of all my lathe work is the 13 x 40. This size machine has the power and stiffness to easily use cutoff blades without experiencing chatter, smaller machines really suffer there. This size machine also has the stiffness to use carbide without difficulty, where as smaller machines favor HSS tooling because tool drag is much less. You will be tempted to buy Chinese, they are good value for money, but typically they are

9 speed machines or less and that is NOT enough. Never choose a machine that does not have spindle speeds below 90 RPM. Lower speeds are far more valuable than higher speeds. This is especially true if you should be fortunate enough to locate a gap bed machine. Although in my experience, I do not generally need that extra swing, but it does happen from time to time. Additionally, the 13 x 40 machine will be equipped with cooling and the very good machines may have a spindle clutch and brake, which is very handy when doing setups and threading operations. As far as the required footprint, if you can allocate a 6' x 2.5' space, you are golden. Steve

enough and has serious other restrictions, like the

usually included in a used machine. For pretty much

tooled condition.

double the price but that one has issues, too...

Ah, I was under the impression that they are all made oversize for the final turning down on each particular machine. At least that is what the LMS adapters are.

This is kind of my point: There are 297 adapters listed in that section. Which one do you pick for this machine? Personally I would prefer to get one that at least somewhat matches the spindle than have to make the whole thing from scratch. With a known common type such as "10 inch 3-jaw with a A1-6 mount" I know what everyone is talking about. The one adapter you linked would clearly not fit this machine. I looked at all 297 and could not decide which one would.

Thanks. This gave me a point of reference. I went and had a look at the Grizzly web site. Their G9729 has (presumably??) the same spindle. I read the manual (their manuals are far superior to anything out of Busy Bee). It seems this flange will not take any chuck bigger than 6". And there were other caveats.

The more I read the less I like it...

All you need is a chunk of steel or iron the right size. I've made adapters out of scrap hydraulic cylinder rod, a cast-iron pipe coupler and a locating pin from an old Segway fender mold.

Barbell weights are the right shape, though the iron may be difficult to cut. A few days of cooking inside the wood stove might soften then up enough, it works well with flame-cut hot rolled steel.

Fitting an adapter to the spindle is easier if the adapter is on a mandrel between centers so you can check the fit and replace the adapter exactly concentric, to remove another half thousandths all the way around. You could bolt it to the flange to cut it almost to size quickly.

5" is a reasonable size for the chuck on a 10" lathe. You don't want it to hit the carriage. I have a 5" 3 jaw and a 6" 4 jaw and have to be very careful with the larger one, or set a stop.

jsw

That presupposes a degree of skill on my part :-) I was doing a dry run in my mind and got stuck at stage one: Getting the right holes drilled in the right places if you cannot remove the flange and use transfer punches. But I guess careful measurement would suffice. The next stage would involve a very interrupted cut which presumably is not an issue with a lathe this size. BTW can you part the piece out by having the parting tool at 90 degrees to the usual direction? Cutting into the piece at the right angles with the tool lined up along the lathe bed? I have seen it done with a wood lathe.

The good thing is that one would not have to cut large internal threads for this spindle.

Here is a question then: Say you have a 9" swing lathe and a 8" diameter,

0.25" thick plate of mild steel than needs a 6.5" hole bored in the centre. You cannot hold it on the outside in a chuck. You cannot clamp it outside on a face plate, even a wooden one. Not enough space for the clamps. What do you do? Would making an 8" sacrificial face plate and super gluing the work piece to it work? Would you cut the hole with a mill on a rotary table? None of the above?

[ ... ]

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No! The blade of the parting tool would need to be curved like a parenthesis on a radius to match the cut to be made. This is called a trepaning tool. A standard parting tool would bind on the outside below the cut.

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What I would do is to mount the faceplate (which is probably larger in diameter than the chucks), coat the surface with double-sided tape, approximately center the workpiece, and using a live center with a flat pusher in it -- or a turned piece of aluminum with a large center hole drilled not all the way through, and use the tailstock and this to press the workpiece against the faceplate. Better if your pusher is turned to press near the OD and relieved a bit inside that.

This is used to press the (slightly oversized) workpiece firmly against the plate to get the tape to grip firmly. Then (using very slow speeds) drill through the center with a bit which fits your lathe -- perhaps a 1/2" one unless you can find a Morse taper shank drill to fit the tailstock taper.

Then, using a boring bar, bore through the workpiece slowly increasing the size until it is the right ID.

Then -- put on the 3-jaw chuck (assuming that you don't need the OD to be truly concentric with the bored hole) expand the jaws inside th bored hole to grip the workpiece so you can turn the OD to something close to concentric.

If you need the two to be truly concentric, turn the OD while still holding the workpiece against the faceplate with the live enter and pusher adaptor. Then shift to boring the OD.

Yes -- the super glue (or a bearing mount Loctite) would work in place of the double-sided tape. You will need to use heat to release it.

And -- while boring, it would probably help to have an extra sacrificial aluminum plate between the workpiece and the faceplate so you don't cut the faceplate.

Of course if the plate which you are machining can tolerate some holes in its surface -- perhaps in places which would be machined larger later -- drill and tap for bolts to hold it to the faceplate..

And yes -- you could use a rotary table and the double-stick tape or glue again on the mill to do the same thing. The finish of the bore will probably not be as nice, however.

Note that you can probably use a larger diameter 4-jaw on the lathe than the 3-jaw because the jaws are easier to adapt to not stick out as far. My 12x24" Clausing has a 6-1/4" 3-jaw, and a 10" 4-jaw.

In your particular described situation, a 9" swing lathe, and an

8" diameter workpiece, *if* your jaws for an 8" 4-jaw chuck have the last step only 1/2" thick, you could just barely grip the 8" diameter workpiece with the jaws extending only partially beyond the OD of the chuck. Be very careful when doing this:

1) Make sure that it does not hit the bed or the wings of the carriage, and that the tool can reach fully through the workpiece without bringing a part of the carriage into contact with the jaws.

2) Don't crank down too tight on the jaws. Extended even a single step beyond the OD of the body puts an extra stress on them.

Or -- you could perhaps make extended soft jaws for the 3-jaw chuck if it has two-piece jaws. You can extend them far enough to grip the OD of the workpiece, and make them of aluminum so you are less likely to damage the bed if you don't adjust things quite right.

Good Luck, DoN.

Makes sense! Like making a hole in the head. Do I take it that you need various sizes trepanning tools to cut different radii?

I take it at this stage you have removed the pusher and relying solely on the double sided sticky tape.

From then on it is a piece of cake - it is that first step that I could not solve without engaging in what I considered a rather sporting activity. Glad to know it is an acceptable way to do it.

Right. I allowed for that. I thought the holding would be better with SG than the tape.

I was thinking a recess as I have done with wood. But this is simpler.

That is what I thought. And using my boring head to 6" on my mini-mill is probably pushing it :-) I did manage 3-1/8"...once!

OK, it sounds like additional reason to use the faceplate method.

I picked that example so you *could not* use the 4-jaw. I have run into that problem several times. I really wanted to know what is an accepted way of dealing with pieces that have a diameter approaching the lathe swing.

Thanks a lot. I shall try this on a smaller scale (4") and be ready to duck if things fly at 550 rpm :-)

One of my old books shows an offset spindle added to a lathe to turn oversized disks. A gear or pulley on the main spindle turns the faceplate on the new spindle at a reduced speed. The geometry is difficult with pulleys but the planetary reduction off a burned-out electric winch might fit well, bolt the large internal ring gear to the faceplate and drive it with the small sun gear.

The added spindle goes above and behind the main one so the tool post is still in the right front-rear position.

jsw