Machining thin disks on a lathe

It looks as though they have online sales, but I can't get the price information, even after adding one to the shopping cart. (Nor can I see any other information about the item.) Perhaps it insists on only talking to Microsoft's "Internet Explorer". :-)

There's another problem. It is designed to fit into 5C collets or 16C collets -- with a bore of 1". I don't think that there is one of that size available for your machine, as a 5C collet needs at least a

Good Luck, DoN.

I didn't know that. So then as I was beginning to think, one would not be able to take full advantage of any chuck that was over 3-1/2".(I was only using that 5" as an example of the size that the lathe would take). Here's another 5", 3-Jaw they advertise as being compatible with the lathe we have:

This is just the sort of stuff you never read in catalogs. So I now have to figure out what is the "largest" chuck that I could use on my lathe to hold the "largest" work pieces.

I guess machining a new set of jaws out of Aluminum is not plausible. :-)

What I'd do is make a hard wooden holder with a hole that would be the same diameter as that of the disks, and the appropriate depth(and a small hole all the way through the center so that glue will dry when used along with a press fit of the disks into the holder. The holder would then go into the normal chuck.

Or perhaps brush some liquid insulation around the perimeter of the disks and let dry. The kind used on electrical wires. It peels off easily.

That's odd.

Actually, Verizon internet service is crap, so I guess it's not odd.

When I have these kind of problems with Verizon, I use my hotmail address which is the same as my name, except backwards(Harrisdarren).

Darren Harris Staten Island, New York.

According to :

One can use larger chucks, but the added weight hastens wear on the bearings.

And you have to be careful that the extended jaws do not hit the ways, or the side arms of the carriage, if your carriage has them. IIRC, it does not.

Note that photo on that web page includes the second set of reverse jaws for gripping larger workpieces. But, because of the steps, they can't grip a great length, so you need support (steady rest) once the length of the workpiece exceeds a certain percentage of the step length.

Part of that is a function of how long the workpieces are. And, whether you have a steady rest to help support the workpiece.

Why not? Where do you think the jaws come from? Actually, the Taig soft jaws are easier to make than most, because there is not the middle step to give precise location which is present on most master jaws. All the Taig jaws have to offer are the screws which hold them on.

Note that the "Pie" jaws are actually made from electronics heat-sink extrusion, which is why all the fingers.

Now -- This applies only to the top jaws to go onto existing master jaws. For making complete jaws from scratch, you need to consider how you are going to make the scroll teeth on the bottoms of the jaws. Each of the three jaws has the teeth at a different offset, so the three jaws wind up close to center when the chuck is assembled.

Note that wood, even hardwood, changes dimensions with the ambient humidity. You can't keep any kind of precision with wood.

I doubt that it would hold very well, but you are welcome to try, and report back on the results.

It does not seem to belong to Verizon. The IP address which is returned from an nslookup of "mail.con2.com" is 204.251.15.174, and a reverse lookup on that yields:

OrgName: Zipa, LLC OrgID: ZIPAL Address: 650 Poydras Street Address: Suite 1015 City: New Orleans StateProv: LA PostalCode: 70130 Country: US

And that is two layers down from Sprint as the top level owner of the netblock.

Unless someone has been playing games with the DNS, this is quite strange.

Enjoy, DoN.

That's the problem!

When you said that you tried to answer an e-mail from me, I thought that you were using the send to respond to the last e-mail I wrote you.

snipped-for-privacy@mail.con.com is the now defunct Staten Island ISP that I originally signed up with Deja.com -> Google Groups.

Obviously this time you weren't trying to respond directly to the e-mail I sent from. But instead via the newsgroups.

The e-mail you wanted to respond to is Staten.islander(NO-SPAM)@verizon.net

(There was/is no way to change things, but at least I'm not getting all the spam that probably goes to the original e-mail I had).

Darren Harris Staten Island, New York.

According to :

I was!

But -- it is still in your headers -- both in the newsgroups (to this moment), and in the e-mail which you last sent me -- which appears to have been sent by you as e-mail in reply to a posting in the newsgroup.

I don't *send* e-mail responses to newsgroup postings -- unless I feel that someone is about to damage some equipment, and want to reach them as quickly as possible.

I *can't* even send e-mail from the machine which I use for Newsreading, so I have to jump through hoops to send an e-mail response, mostly cut-and-paste to another machine.

I was trying to respond to an e-mail which I received -- though

Note the quoted headers (somewhat trimmed -- snips marked) from your e-mail:

====================================================================== From snipped-for-privacy@mail.con.com Tue Feb 14 00:37:40 2006 Return-Path:

Received: from mproxy.googlegroups.com (216.239.56.131) by cadeau.d-and-d.com with SMTP; 14 Feb 2006 05:37:40 -0000

From: snipped-for-privacy@mail.con.com To: "DoN. Nichols" Subject: Re: Tool Terms Date: Mon, 13 Feb 2006 21:37:28 -0800

X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; Win 9x 4.90; (R1 1.3);

I note that you are using google to read newsgroups, and perhaps that confused your attempt to post to the newsgroup and turned it into an e-mail reply instead.

It was not in the headers.

There is that.

I'll put the new address onto the bounced e-mail, though we have moved way past that by now, I think.

Thanks, DoN.

Good distinction.

I would not try to part off such thin disks. A machinist I know does custom washers of sorts, and has the approx OD sheared square out of sheet, then drills an approx center hole, then stacks them and turns them. The corners hack off initially, and you need a much lower rpm, but eventually the turning gets easier. Would certianly be nicer to have them punched out round, then turned, if nec. Chamfering them is a goddamm pita, tho--one by effing one, sandwiched between heavy disks (collet, live center). Also you could stack/separate a bunch, and have one tool hit them all--a pita to set, tho.

-- Mr. P.V.'d formerly Droll Troll

I'm thinking more in terms of diameter.(Flat stock).

What I meant was that I don't think he has the equipment for machining the jaws himself.

Sounds like a CNC job to me. Or a job for an experienced machinist.

It shouldn't be too extreme. Especially since the work is not big and heavy. And a facing operation will not pull it out of the holder. But one can use glue if a small hole is place in the center for ventilation so the glue will dry.

But if it is still an issue then an option is Delrin which doesn't soak up moisture and has excellent dimensional stability.

It's job would be to just keep the jaws from damaging the workpiece.

Darren Harris Staten Island, New York.

According to :

First off -- I got two e-mails from you today -- with the old return address which your usenet articles show. I am not going to bother typing answers to them, only to have the answers sit for a week and then pop back up as undeliverable.

O.K. For that, it should suffice. Obviously a 4-jaw independent is what is needed.

"He"? Who else came into this thread?

If you have milling attachments for the lathe, you can make soft jaws -- especially the ones for the Taig with its simple mount.

It used to be done with the jaw blanks mounted on a fixture on an index head which was geared to the X-axis leadscrew on a milling machine. The index head would turn fairly slowly (from a power feed), and the gears would turn the leadscrew to provide the proper feed per turn. A small endmill would cut the spiral threads in the back of the jaws. (Quite probably, the fixture would hold two sets of jaws at once to improve production and to minimize the amount of time spent cutting air.) A similar setup would machine the scroll plate for inside the jaws. The jaws would be shaped, and hardened, and then the two sets of scroll teeth would be lapped -- either together, or on separate fixtures. This would shape the teeth to allow handling the varying radius as the jaws close or open.

Yes -- it could be one with CNC now -- but it may be more economical to use the old machines if they still work well.

A friend made a copy of an old instrument called a "hudry-gurdy". Not the barrel organs, but rather a stringed instrument in which the strings were bowed by the rim of a wooden wheel. Well, the problem was that as the wood dried out, what had started with a nice round wheel shrunk differently along the grain and across it, so it was pressing harder on the strings during part of its rotation than during other parts. It could not be kept in a shape good enough to produce a steady sound.

I finally machined one for him from plexiglass, which would not shrink. The only problem was that I put too good a polish on the rim, and it would not hold rosin to drive the strings. :-) He solved that with a strip of wood veneer with a diagonal join.

So -- yes, wood *does* shrink enough to be a problem as it dries. The original ones were almost certainly made with wood which had been dried for decades before being shaped put to use, not modern kiln-dried wood.

Delrin, a set of radial grooves from the center hole to near the outside diameter, and a vacuum pump sucking on the center hole to keep the workpiece in place.

But probably not for stainless steel. :-)

Oh -- that is what aluminum soft jaws are for. When they are machined in place in the chuck (in the lathe) the shape is such that they will match the curve of the OD of the workpiece, so there is no sharp edge trying to indent the workpiece.

Enjoy, DoN.

I don't even bother with people that post to me privately when the post is a usenet posting that they are responding to. As far as I am concerned, those idiots are just arogant itiots with a bit of paranoia and need to be ignored. If I posted something on the usenet, I expect replies on the usenet. I bet the guy is still getting a bunch of spam even tho he's munged his email addres anyway.

-- Why do penguins walk so far to get to their nesting grounds?

I wouldn't intentionally respond with a direct e-mail to a newsgroup post. My home pc went down last week and I was posting from the library, so that may have been the problem.

I was referring to the original poster.

Ok. Those "teeth" seem difficult to me. I thought they were courved, and that tolerance was very critical.

But I assume that you don't recommend using a lathe for this, correct?

Solution: Keep a spray bottom filled with water handy. :-)

Sounds like a complicated set-up for such a "simple" project.

That's if he had or could find aluminum jaws. :-)

Darren Harris Staten Island, New York.

According to :

Yep. I found the articles, and posted a followup to one of the two.

O.K. You're talking about machining entire jaws from scratch, while I was talking about machining new "top" jaws to bolt onto a master jaw which remains in the chuck body. Quite a different task.

The chucks designed for this (such as my Bison 3-jaw) have a hardened "master" jaw in the body of the chuck, almost flush with the top of the chuck surface. They also come with a hardened set of top jaws for normal lathe use, except that if you need outside gripping jaws, you can unbolt and reverse the top jaws without having to remove the master jaws and replace them, as you have to do with normal one-piece jaws. There are also available from the maker or others sets of mild steel soft jaws, which start out with no steps at all -- full height all the way along the length. This, you bolt to the chuck's master jaws, and then (after blocking the jaws in place with something appropriate), you turn them in the lathe and chuck to make a set of jaws precisely designed to hold your workpiece -- for any project where you are going to need to make a lot of the same thing. These can be the right diameter to hold the workpiece precisely (more accurately than with the standard jaws), and can be bored with a step to ensure that each workpiece is installed to the proper depth without having to measure each time.

Normally, such a set of soft jaws is set aside with the other special tooling for a project, and returned to the chuck when you have to make that again.

However, if you don't expect any more of those, you set the soft jaws aside until you have another project which can benefit from soft jaws, and re-bore the jaws to fit the new (obviously somewhat larger) job. Usually, they can go through several re-borings before there is not enough metal left to re-bore them again.

Normal two-piece jaws have a longitudinal groove on the under surface which matches a raised rib on the master jaw, and a cross-groove across the middle of the top jaw which mates with a raised rib across the master, thus giving accurate location in both directions when replacing a soft jaw on its master jaw. (You should always mark the soft jaws so you can restore them to the same master jaw each time, or you lose a bit of the accuracy which is otherwise possible.

The 3-jaw chuck for the Taig has only the longitudinal groove, with the radial location being done by the bodies of the screws which attach the top jaws to the master jaws, so they are not quite as precisely repeatable. But they also come only with aluminum soft jaws, not with mild steel which is common with others.

In any case, it is easy enough to mill the underside of the stock to make jaws and drill and counterbore the holes for the screws which attach the top jaws to the master jaws.

Making entire one-piece chuck jaws, however, is a much more difficult task, and not what I was referring to.

I do not. The problems, as I see them, are:

Hardly. The majority of the instrument was made of wood, glued together.

Sometimes, that is the best way to go.

As long as your chuck has two-piece jaws, you can make more aluminum (or steel) jaws with a milling machine.

Enjoy, DoN.