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double headed coin
I was wondering if anyone would know where I could have a double headed
coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks. |
doomtrain wrote:
I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks. get two coins, mill them down to half thickness; solder the two halves together. Any machinist could do this. Whether they would want to is another matter. |
doomtrain wrote:
I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks. I have done this several times with nickels. The instructions for it I found once in this news group. Quite easy to do. Abrasha http://www.abrasha.com |
"Abrasha" wrote in message ... doomtrain wrote: I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks. I have done this several times with nickels. The instructions for it I found once in this news group. Quite easy to do. Abrasha http://www.abrasha.com Indeed. ....and *don't* mill both faces flat. The join is then way too easy to spot. Instead, turn a recess in one face, leaving the rim intact. Then turn the other coin to fit the recess. A good press fit won't require solder, and if turned coincident with the rim will be virtually undetectable. A fun exercise - but if you just want a double-header, they're available for a few bucks on the 'net. Google is your friend. -- Jeff R. |
"Jeff R" wrote in message
u... Then turn the other coin to fit the recess. A good press fit won't require solder, and if turned coincident with the rim will be virtually undetectable. So, how do you hold it to turn down the rim? A fun exercise - but if you just want a double-header, they're available for :) |
In article , Mike Young says...
So, how do you hold it to turn down the rim? One way would be with a pot collet and a pressure pad in the tailstock. The recess in the collet should be less than half the thickness of the coin - you'll need a setup like that anyway to face off half the thickness. So the drill would be: Put coin in pot collet, apply pressure via tailstock pad to face of coin. Turn half the rim down to the reduced diameter. Then swap to the second pot collet, which has a diamter sized for the turned-down portion. Install the coin the other way around and turn down the remaining half of the rim diameter. Then in the same setup pull back the pressure pad and carefully face half the thickness away. The advantage of the bore and press approach is you can do this on coins with "coining" (the knurling around the circumference) without having to match up the knurling when supergluing them together. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Which would be better, super glue or solder?
-- Roger Shoaf If knowledge is power, and power corrupts, what does this say about the Congress? "jim rozen" wrote in message ... In article , Mike Young says... So, how do you hold it to turn down the rim? One way would be with a pot collet and a pressure pad in the tailstock. The recess in the collet should be less than half the thickness of the coin - you'll need a setup like that anyway to face off half the thickness. So the drill would be: Put coin in pot collet, apply pressure via tailstock pad to face of coin. Turn half the rim down to the reduced diameter. Then swap to the second pot collet, which has a diamter sized for the turned-down portion. Install the coin the other way around and turn down the remaining half of the rim diameter. Then in the same setup pull back the pressure pad and carefully face half the thickness away. The advantage of the bore and press approach is you can do this on coins with "coining" (the knurling around the circumference) without having to match up the knurling when supergluing them together. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
jim rozen wrote:
In article , Mike Young says... So, how do you hold it to turn down the rim? One way would be with a pot collet and a pressure pad in the tailstock. The recess in the collet should be less than half the thickness of the coin - you'll need a setup like that anyway to face off half the thickness. So the drill would be: Put coin in pot collet, apply pressure via tailstock pad to face of coin. Turn half the rim down to the reduced diameter. Then swap to the second pot collet, which has a diamter sized for the turned-down portion. Install the coin the other way around and turn down the remaining half of the rim diameter. Then in the same setup pull back the pressure pad and carefully face half the thickness away. The advantage of the bore and press approach is you can do this on coins with "coining" (the knurling around the circumference) without having to match up the knurling when supergluing them together. Jim What's the best way to hold the other coin, the one you bore out? I'd think a soft collet recessed to suit ought to be safer than a chuck. Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
On Sun, 11 Sep 2005 17:50:24 +1000, Jeff R wrote:
...and *don't* mill both faces flat. The join is then way too easy to spot. Instead, turn a recess in one face, leaving the rim intact. OK, that's easy, but: Then turn the other coin to fit the recess. How do I hold it while I'm turning the OD, please? A fun exercise - but if you just want a double-header, they're available for a few bucks on the 'net. Google is your friend. |
"Jeff Wisnia" wrote in message ... snip--- What's the best way to hold the other coin, the one you bore out? I'd think a soft collet recessed to suit ought to be safer than a chuck. Jeff Soft jaws. They don't crush or distort, nor do they move in a lateral direction when tightened, unlike a collet. They're also very fast and precise. Harold |
Roger_Nickel wrote:
doomtrain wrote: I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks. get two coins, mill them down to half thickness; solder the two halves together. Any machinist could do this. Whether they would want to is another matter. No, this is absolutely the wrong way to do this. The right way is to bore out one side of one coin, do the same with a second identical coin, remove the edge of that second coin and then press fit that into the bored out space of the first coin. Soldering two halves anneals the coins, and results in a coin that makes a thud on a hard surface when dropped. IF you are even capable of soldering the two halves together accurately which is highly questionable. Using "my" (I did not invent this) method, results in a double headed coin, that sounds just like a regular one when dropped onto a hard surface. Abrasha http://www.abrasha.com |
Roger Shoaf wrote:
Which would be better, super glue or solder? Neither, press fit is the better solution. -- Abrasha http://www.abrasha.com |
Dave Hinz wrote:
... Jeff R ... wrote: ...and *don't* mill both faces flat. The join is then way too easy to spot. Instead, turn a recess in one face, leaving the rim intact. OK, that's easy, but: Then turn the other coin to fit the recess. How do I hold it while I'm turning the OD, please? .... See Jim Rozen's post, and also see text and pictures at: http://www.metalworking.com/dropbox/...s/nickel21.jpg http://www.metalworking.com/dropbox/...s/nickel22.jpg http://www.metalworking.com/dropbox/...s/nickel23.jpg http://www.metalworking.com/dropbox/...ickel2head.txt from "Two headed nickel" r.c.m thread of August 2003, http://groups.google.com/groups?q=%2...aded+nickel%22 That google groups page also lists a couple of 2-headed- coin suppliers, like another poster mentioned. However, the coins the OP wants joined are silver dollars, rather than nickels or quarters. Although his email to me didn't say, I presume that by silver dollars he means some pre-1935 coins, not Eisenhower's, Anthony's or Sacagawea's . -jiw |
On Sun, 11 Sep 2005 12:45:48 -0600, James Waldby wrote:
Dave Hinz wrote: How do I hold it while I'm turning the OD, please? See Jim Rozen's post, and also see text and pictures at: http://www.metalworking.com/dropbox/...s/nickel21.jpg Thanks, James (and Jim)! Dave |
Correct these dollars are 1885 silver dollars.
|
Harold and Susan Vordos wrote:
"Jeff Wisnia" wrote in message ... snip--- What's the best way to hold the other coin, the one you bore out? I'd think a soft collet recessed to suit ought to be safer than a chuck. Jeff Soft jaws. They don't crush or distort, nor do they move in a lateral direction when tightened, unlike a collet. "Lateral"? I'd call it "axial" like the collet and work moves along the axis of the spindle, toward the headstock, when tightened. Then again, they do move laterally when viewed from where you usually stand relative to a lathe, so I guess either description is correct. :-) They're also very fast and precise. Agreed, Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
James Waldby wrote:
Dave Hinz wrote: ... Jeff R ... wrote: ...and *don't* mill both faces flat. The join is then way too easy to spot. Instead, turn a recess in one face, leaving the rim intact. OK, that's easy, but: Then turn the other coin to fit the recess. How do I hold it while I'm turning the OD, please? ... See Jim Rozen's post, and also see text and pictures at: http://www.metalworking.com/dropbox/...s/nickel21.jpg http://www.metalworking.com/dropbox/...s/nickel22.jpg http://www.metalworking.com/dropbox/...s/nickel23.jpg http://www.metalworking.com/dropbox/...ickel2head.txt from "Two headed nickel" r.c.m thread of August 2003, http://groups.google.com/groups?q=%2...aded+nickel%22 Those were exactly the instructions I was talking about before. Abrasha http://www.abrasha.com |
The retired two headed nickle pictures show how I made
the two headed nickle. But I have more pictures if anyone would like to see them. I used a soft collet but soft jaws would work just fine. I gave all the ones I made to friends or I would send one to doomtrain. Jim Sehr Email me if you would like pics and I will find them on my hard drive and send them to you. "Abrasha" wrote in message ... James Waldby wrote: Dave Hinz wrote: ... Jeff R ... wrote: ...and *don't* mill both faces flat. The join is then way too easy to spot. Instead, turn a recess in one face, leaving the rim intact. OK, that's easy, but: Then turn the other coin to fit the recess. How do I hold it while I'm turning the OD, please? ... See Jim Rozen's post, and also see text and pictures at: http://www.metalworking.com/dropbox/...s/nickel21.jpg http://www.metalworking.com/dropbox/...s/nickel22.jpg http://www.metalworking.com/dropbox/...s/nickel23.jpg http://www.metalworking.com/dropbox/...ickel2head.txt from "Two headed nickel" r.c.m thread of August 2003, http://groups.google.com/groups?q=%2...aded+nickel%22 Those were exactly the instructions I was talking about before. Abrasha http://www.abrasha.com |
" Jim Sehr" wrote in message ... The retired two headed nickle pictures show how I made the two headed nickle. But I have more pictures if anyone would like to see them. I used a soft collet but soft jaws would work just fine. They're far better suited to the application than a collet. Collets are influenced by the diameter of the object, so they don't close in the same place each time---limiting your ability to control thickness to some degree. If you have a Hardinge-Sjogren collet chuck, it's even more pronounced. Soft jaws, properly bored with a step, eliminate that problem and hold the coin perfectly perpendicular. Harold |
Harold and Susan Vordos wrote:
" Jim Sehr" wrote in message ... The retired two headed nickle pictures show how I made the two headed nickle. But I have more pictures if anyone would like to see them. I used a soft collet but soft jaws would work just fine. They're far better suited to the application than a collet. Collets are influenced by the diameter of the object, so they don't close in the same place each time---limiting your ability to control thickness to some degree. If you have a Hardinge-Sjogren collet chuck, it's even more pronounced. Soft jaws, properly bored with a step, eliminate that problem and hold the coin perfectly perpendicular. Harold I used external gripping step collet from my lathe. I have a two sets of 5 internal and external step collets especially made for it. They worked perfectly for this. See http://www.lathes.co.uk/tos/page3.html (bottom photo) Abrasha http://www.abrasha.com |
"Abrasha" wrote in message ... Harold and Susan Vordos wrote: " Jim Sehr" wrote in message ... The retired two headed nickle pictures show how I made the two headed nickle. But I have more pictures if anyone would like to see them. I used a soft collet but soft jaws would work just fine. They're far better suited to the application than a collet. Collets are influenced by the diameter of the object, so they don't close in the same place each time---limiting your ability to control thickness to some degree. If you have a Hardinge-Sjogren collet chuck, it's even more pronounced. Soft jaws, properly bored with a step, eliminate that problem and hold the coin perfectly perpendicular. Harold I used external gripping step collet from my lathe. I have a two sets of 5 internal and external step collets especially made for it. They worked perfectly for this. See http://www.lathes.co.uk/tos/page3.html (bottom photo) Abrasha http://www.abrasha.com Where that kind of setup tends to fall short is in holding items when production machining and you rely on fixed register points (the step in a collet, or step chuck, for example).. Mind you, I'm not suggesting that they don't work well----far from it. It's just that there are times when a thou makes a huge difference, and collets generally won't register close enough to hold the tolerance. I'm not speaking of concentricity, but holding lengths. Soft jaws are repeatedly reliable for that operation. I've run countless production jobs by both methods and have resorted to a fixed stop in the spindle of a machine in lieu of relying on a collet with a step, or collet stop, when collets were better adapted to the job at hand. Small parts run at high spindle speed is a good example. Do keep in mind I use a Hardinge-Sjogren collet chuck. A lathe equipped with a lever closer is more likely to repeat, but only when each item is held to a close holding diameter, wavering no more than a thou. Harold |
In article , Harold and Susan Vordos says...
Where that kind of setup tends to fall short is in holding items when production machining and you rely on fixed register points (the step in a collet, or step chuck, for example).. Mind you, I'm not suggesting that they don't work well----far from it. It's just that there are times when a thou makes a huge difference, and collets generally won't register close enough to hold the tolerance. I'm not speaking of concentricity, but holding lengths. Soft jaws are repeatedly reliable for that operation. I've run countless production jobs by both methods and have resorted to a fixed stop in the spindle of a machine in lieu of relying on a collet with a step, or collet stop, when collets were better adapted to the job at hand. Small parts run at high spindle speed is a good example. Do keep in mind I use a Hardinge-Sjogren collet chuck. A lathe equipped with a lever closer is more likely to repeat, but only when each item is held to a close holding diameter, wavering no more than a thou. Remember this is a one- or two-off project though. But you are of course 100% correct. Even good lever closers won't hold even a halfway decent length tolerance plain collets. Story: Say one had an elderly parent who spent a *lot* of time in a hospital this summer. Further consider that said hospital wanted to ding the relatives two bucks each time they exited the parking lot. But they had a token system so the relatives didn't have to plug in two bucks of quarters at the exit gate. Further imagine that the tokens were nothing more than brass slugs with some fancy stamped designe and a raised rim. And that a trial effort at reproducing one worked splendidly. Then consider that one might just possibly have a hardinge turret lathe at one's disposal. The problem one finds is that the only way to accurately get the thickness of the part under control is: a) barfeed the stock to a stop in the turret, b) perform a facing operation to set the extension of the stock from the collet, within a thou, and c) parting off the slug from the stock with the cutoff tool. Because the stock draws back into the spindle a large (over 15 thou) and non-repeatable (+/- five thou or so) one *has* to waste material and another operation to get the thickness tolerance inside a thousanth. All, hypothetically speaking of course. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Harold and Susan Vordos wrote:
I used external gripping step collet from my lathe. I have a two sets of 5 internal and external step collets especially made for it. They worked perfectly for this. See http://www.lathes.co.uk/tos/page3.html (bottom photo) Abrasha http://www.abrasha.com Where that kind of setup tends to fall short is in holding items when production machining and you rely on fixed register points I am certain that the original poster is not interested in doing production machining of double headed coins. That IS the subject of this thread. This was the original post: "I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks." As you can see, he just wanted ONE double headed coin made. A lathe equipped with a lever closer is more likely to repeat, but only when each item is held to a close holding diameter, wavering no more than a thou. My lathe is equipped with a lever closer See http://www.lathes.co.uk/tos/page3.html, and as far as I know nickels are within a couple thousands of each other. Nickels being the only coins I have made double headers out of. Abrasha http://www.abrasha.com |
"Abrasha" wrote in message ... Harold and Susan Vordos wrote: I used external gripping step collet from my lathe. I have a two sets of 5 internal and external step collets especially made for it. They worked perfectly for this. See http://www.lathes.co.uk/tos/page3.html (bottom photo) Abrasha http://www.abrasha.com Where that kind of setup tends to fall short is in holding items when production machining and you rely on fixed register points I am certain that the original poster is not interested in doing production machining of double headed coins. That IS the subject of this thread. This was the original post: "I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks." As you can see, he just wanted ONE double headed coin made. So you're suggesting that learning something that he may not have previously known is bad? If not, and you're trying to extol the virtues of collets to someone that has used them for a lifetime, you're wasting your time. I've yet to find a collet that will duplicate the performance of soft jaws-----the sole exception being when the parts are small and *not* short. You can include step chucks in my comments, of which I own several, including the closers. I also have internal collets. Machining wasn't a hobby for me, it was my livelihood, one I took very seriously. I'm not exactly short on experience. You seem to misunderstand that I'm not bad mouthing your setup-----which I'm sure worked adequately for your purpose. Assuming one has a lathe and a three jaw chuck that accommodates soft jaws, do you really think they'd benefit by buying the collet setup to machine these coins when it can be done by simply machining existing soft jaws? I'd have the job run before you'd returned from town with the collet. Be certain to read Jim's post. There are times when collets simply fall right on their collective asses. That was, and is, my point. Harold |
Harold and Susan Vordos wrote:
"Abrasha" wrote in message ... Harold and Susan Vordos wrote: I used external gripping step collet from my lathe. I have a two sets of 5 internal and external step collets especially made for it. They worked perfectly for this. See http://www.lathes.co.uk/tos/page3.html (bottom photo) Abrasha http://www.abrasha.com Where that kind of setup tends to fall short is in holding items when production machining and you rely on fixed register points I am certain that the original poster is not interested in doing production machining of double headed coins. That IS the subject of this thread. This was the original post: "I was wondering if anyone would know where I could have a double headed coin made. I have both coins and would like to know if theres such a place or person that I could hire to have that done. thanks." As you can see, he just wanted ONE double headed coin made. So you're suggesting that learning something that he may not have previously known is bad? No, at least not intentionally If not, and you're trying to extol the virtues of collets to someone that has used them for a lifetime, you're wasting your time. I've yet to find a collet that will duplicate the performance of soft jaws-----the sole exception being when the parts are small and *not* short. You can include step chucks in my comments, of which I own several, including the closers. I also have internal collets. Machining wasn't a hobby for me, it was my livelihood, one I took very seriously. I'm not exactly short on experience. You seem to misunderstand that I'm not bad mouthing your setup I did not take it as such. -----which I'm sure worked adequately for your purpose. It did indeed. Assuming one has a lathe and a three jaw chuck that accommodates soft jaws, do you really think they'd benefit by buying the collet setup to machine these coins when it can be done by simply machining existing soft jaws? I'd have the job run before you'd returned from town with the collet. You're probably right. Abrasha http://www.abrasha.com |
"Harold and Susan Vordos" wrote in message ... So you're suggesting that learning something that he may not have previously known is bad? If not, and you're trying to extol the virtues of collets to someone that has used them for a lifetime, you're wasting your time. I've yet to find a collet that will duplicate the performance of soft jaws-----the sole exception being when the parts are small and *not* short. You can include step chucks in my comments, of which I own several, including the closers. I also have internal collets. Machining wasn't a hobby for me, it was my livelihood, one I took very seriously. I'm not exactly short on experience. You seem to misunderstand that I'm not bad mouthing your setup-----which I'm sure worked adequately for your purpose. Assuming one has a lathe and a three jaw chuck that accommodates soft jaws, do you really think they'd benefit by buying the collet setup to machine these coins when it can be done by simply machining existing soft jaws? I'd have the job run before you'd returned from town with the collet. Be certain to read Jim's post. There are times when collets simply fall right on their collective asses. That was, and is, my point. Why beat around the bush, tell how you really feel. -- Roger Shoaf If knowledge is power, and power corrupts, what does this say about the Congress? |
"Roger Shoaf" wrote in message ... "Harold and Susan Vordos" wrote in message ... snip-- Be certain to read Jim's post. There are times when collets simply fall right on their collective asses. That was, and is, my point. Why beat around the bush, tell how you really feel. -- Roger Shoaf Chuckle! Words seem to fail me! :-) Harold |
In article , Harold and Susan Vordos says...
You seem to misunderstand that I'm not bad mouthing your setup-----which I'm sure worked adequately for your purpose. Assuming one has a lathe and a three jaw chuck that accommodates soft jaws, do you really think they'd benefit by buying the collet setup to machine these coins when it can be done by simply machining existing soft jaws? I'd have the job run before you'd returned from town with the collet. One of the deals with soft-jaw chucks is, they're pretty expensive. They work *great* in a production environment. We used them exclusively at Timco when making crane sheaves. In fact each job has their own set of (expensive) jaws on the shelf (and this was a big set of shelves, six feet high and 8 feet long) that went with each jobs mandrel. They were real time-saver. But hobby machinist can't really afford a chuck like that - and soft jaws on a chuck with a worn scroll don't repeat *that* well. I've gotten to like the somewhat oversize six jaw adjust true chuck (it's an 8" chuck on my 10" SB, looks too big to work but seems to do just fine) that I bought before Dave Ficken went out of business. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
I am not trying to say that you don't know the best way to do this.
But as a hobbiest without a lathe with collets or a chuck that accomodates soft jaws, I think I would try chucking a bit of stock in the lathe, turning the diameter to the diameter of a Nickle, recessing the center slightly so the nickle seats on the rim and then glueing a nickle to the stock using the tailstock to hold it while the adhesive sets. After machining then heating to soften the adhesive. Hot melt adhesive might work for this as long as one took light cuts. Dan |
wrote in message oups.com... I am not trying to say that you don't know the best way to do this. snip Hot melt adhesive might work for this as long as one took light cuts. A standard Jewelry apprentice task was to take a dime (they were almost pure silver when I did this) and cut it in half .. the thin way .. using a jeweler's saw. Actually, you had to do two dimes that way. Then you soldered the two heads back to back. It took me many years to accomplish the task and unfortunately, I long ago lost both the two-headed and the two-tailed dimes. That's the right way to do the trick. One can cheat and file the one side off the two dimes and then solder them together. Not all that difficult to do with soft solders. With silver solder is it much, much, harder to do. Boris -- ------------------------------------- Boris Beizer Ph.D. 1232 Glenbrook Road Huntingdon Valley, PA 19006 TEL: 215-572-5580 FAX: 215-886-0144 Email bsquare "at" earthlink.net ------------------------------------------ |
The (inexpensive) Taig 3 jaw chuck uses soft aluminum top jaws that are machinable just like the big guys. they are not repeatable once removed and replaced though... On 14 Sep 2005 05:30:40 -0700, jim rozen wrote: One of the deals with soft-jaw chucks is, they're pretty expensive. They work *great* in a production environment. We used them exclusively at Timco when making crane sheaves. In fact each job has their own set of (expensive) jaws on the shelf (and this was a big set of shelves, six feet high and 8 feet long) that went with each jobs mandrel. They were real time-saver. But hobby machinist can't really afford a chuck like that - and soft jaws on a chuck with a worn scroll don't repeat *that* well. |
In article , Felice Luftschein and
Nicholas Carter says... The (inexpensive) Taig 3 jaw chuck uses soft aluminum top jaws that are machinable just like the big guys. they are not repeatable once removed and replaced though... Interesting. Even *good* chucks with soft jaws don't repeat that well when swapping between sets. We used to have to true up soft jaws after a few go-rounds because the teeth would wear a bit, and the aluminum would get beat up over time. And here I'm talking about a five thousand dollar chuck. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
sets. After machining then heating to soften the adhesive. Hot melt
adhesive might work for this as long as one took light cuts. I use super glue for things like this. A little heat and they slide right off. It is best to cut some rings in the end of the rod to improve the bond. |
"jim rozen" wrote in message ... In article , Felice Luftschein and Nicholas Carter says... The (inexpensive) Taig 3 jaw chuck uses soft aluminum top jaws that are machinable just like the big guys. they are not repeatable once removed and replaced though... Interesting. Even *good* chucks with soft jaws don't repeat that well when swapping between sets. We used to have to true up soft jaws after a few go-rounds because the teeth would wear a bit, and the aluminum would get beat up over time. And here I'm talking about a five thousand dollar chuck. Jim I've never been able to put soft jaws back where they came from and have them run true. There's simply too many places for error to accrue-----particularly when one expects them to run within .0005", and I do. Yes, mine are numbered, too. The method I use for machining them provides for skim cuts to have them run true once again--so reinstalling them endlessly causes almost zero loss. I use an adjustable "spider" to preload the jaws, setting them such that only a few thou need be removed to get them running true, and to size. I also have a weird habit of holding parts to a uniform size, so they can be run in soft jaws successfully. It's a way of life with me. Harold |
According to jim rozen :
[ ... ] But hobby machinist can't really afford a chuck like that - and soft jaws on a chuck with a worn scroll don't repeat *that* well. How expensive a chuck do you think that you need? I got a very nice Bison 6-1/4" 3-jaw with two-piece jaws, which is all that you need to allow you to use soft jaws. You can then either purchase the soft jaws (fairly expensive), or machine your own, if you have a mill. A horizontal mill would be excellent for making batches of soft jaws of whatever material suited your needs -- mild steel, aluminum, brass? (I've never seen brass top jaws, but other than the slightly greater expense of the metal, does anyone know why it would not serve? Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
"DoN. Nichols" wrote in message ... According to jim rozen : [ ... ] But hobby machinist can't really afford a chuck like that - and soft jaws on a chuck with a worn scroll don't repeat *that* well. How expensive a chuck do you think that you need? I got a very nice Bison 6-1/4" 3-jaw with two-piece jaws, which is all that you need to allow you to use soft jaws. You can then either purchase the soft jaws (fairly expensive), or machine your own, if you have a mill. A horizontal mill would be excellent for making batches of soft jaws of whatever material suited your needs -- mild steel, aluminum, brass? (I've never seen brass top jaws, but other than the slightly greater expense of the metal, does anyone know why it would not serve? Enjoy, DoN. I've never seen them, either, but I can't see any reason they wouldn't work. Expense is likely the chief reason they aren't common. Considering even steel jaws don't mark the work, there's no real advantage in using them. One of the points that I failed to mention about soft jaws in lieu of step chucks or soft collets. Once you've opened up a step chuck or collet, it's often worthless for smaller diameters (depends on the depth). In essence, they're somewhat perishable. Soft jaws, on the other hand, can be re-machined to fit pretty much any contour or size, so they're not rendered useless, or relegated to specific use *unless so desired*. Further, once you've used them up, it's easy to weld in new metal so the process can be started all over again. No need to make new jaws. For that reason, it's nice to use steel in place of aluminum. Aluminum, once welded, would have to be solution annealed and once again artificially aged in order to get back to a desirable hardness. I strongly advise anyone to purchase only chucks with master jaws (two piece jaws) when buying, if at all possible. Even if you think you'll never run production work. They're more than adequate for one off work, often the best possible solution for holding parts. Soft jaws free you up like no other device when it comes to holding objects in your lathe, or even your mill when needed. Harold |
In article , Harold and Susan Vordos says...
I've never been able to put soft jaws back where they came from and have them run true. There's simply too many places for error to accrue-----particularly when one expects them to run within .0005", and I do. Yes, mine are numbered, too. The okuma lathes I worked on used hydraulic chucks, and they were expensive - but one could re-install the jaws carefully, cleaning the teeth with a brush - and they would repeat better than a thou, days later. Mostly it was wear on the jaws that required them to be trued up. Those chucks were scary. We ran ten inch diameter chunks of nylon, a foot long in them, roughing at 3K rpm. For that we turned up the hydraulic pressure. They would set the jaws up so that they only clamped in a tenth or an inch or so - so that there was no chance of getting a finger between the part and the jaw when hitting the foot pedal. Ouch. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
The list price on the Taig chuck is $60.40 (beats $5K!) and spare sets
of jaws are $7.60 and $7.72 for full circle jaws. They also make a 4 jaw chuck with soft jaws for slightly more. Of course it is only a 3.25" dia chuck and is a direct scroll rather than a pinion chuck. I do sell a few to people who use an arbor for mounting the chuck in a 5C collet. What's funny is how many people are confused by the Taig 3 jaw, if only because most beginners machining texts make no mention of the idea of soft jaws. I have a section of pics about truing the Taig jaws he http://www.cartertools.com/picture.html#3JT I also have a Bison 5" chuck that has 2 part jaws, I think it was around $300.00 and is really well made. I have yet to get around to using soft jaws on it though. I guess I should fire up the CNC or as others suggested tool up the horizontal mill... On 14 Sep 2005 12:24:59 -0700, jim rozen wrote: Interesting. Even *good* chucks with soft jaws don't repeat that well when swapping between sets. We used to have to true up soft jaws after a few go-rounds because the teeth would wear a bit, and the aluminum would get beat up over time. And here I'm talking about a five thousand dollar chuck. Jim |
"jim rozen" wrote in message ... In article , Harold and Susan Vordos says... I've never been able to put soft jaws back where they came from and have them run true. There's simply too many places for error to accrue-----particularly when one expects them to run within .0005", and I do. Yes, mine are numbered, too. The okuma lathes I worked on used hydraulic chucks, and they were expensive - but one could re-install the jaws carefully, cleaning the teeth with a brush - and they would repeat better than a thou, days later. That's actually pretty decent. The chuck that came with my Graziano would repeat consistently within a half thou, but almost never if the jaws were removed and re-installed. Mostly it was wear on the jaws that required them to be trued up. That's the chief reason I like steel jaws, although I use both aluminum and steel. The only reason I'd ever re-machine the jaws while running a production run is if I managed to clamp on a chip-----which was rare. (I use air, but well placed). Those chucks were scary. We ran ten inch diameter chunks of nylon, a foot long in them, roughing at 3K rpm. For that we turned up the hydraulic pressure. They would set the jaws up so that they only clamped in a tenth or an inch or so - so that there was no chance of getting a finger between the part and the jaw when hitting the foot pedal. Ouch. I can well imagine! Ever get pinched? I've never operated such a chuck-----ever. I've always been on manual machines, even when running production, of which I've done more than my share. On one job, where I was holding 3/4" hex stainless stock, making hundreds of aircraft parts, I managed to pull a hernia from exerting on the Hardinge-Sjogren collet chuck I use. One of those hydraulic chucks would have looked pretty good! Harold |
In article , Harold and Susan Vordos says...
I can well imagine! Ever get pinched? No, but we did have some part ripouts. A few of them knocked the steel doors of the machine. We ran them with the door interlocks defeated - but it was suicide to leave the doors open on the large jobs. My rule was to never hit that green button until the door was *all* the way closed. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
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