Lathes for smithing.
- Thread starter mattL46
- Start date
Was told the heavier the better. Why? Lighter lathes can do the job, but are less stable. One student grabbed the 10" lathe bed and was able to shake the lathe! 
One gunsmith told us to get 15"! That's one heavy lathe with one heavy four jaw chuck. He says there more stable than the smaller lathes.
Mind you, the lathe Saint John Moses Browning had (that his father Johnathan hauled across the country) was a small lathe. Yet it got the job done.
BTW, I played with a small SouthBend that was made in Taiwan. Boo! Hiss! It's not like the old SouthBends that were made here back in the '40s. I'll take those old ones over a new one.
One gunsmith told us to get 15"! That's one heavy lathe with one heavy four jaw chuck. He says there more stable than the smaller lathes.Mind you, the lathe Saint John Moses Browning had (that his father Johnathan hauled across the country) was a small lathe. Yet it got the job done.
BTW, I played with a small SouthBend that was made in Taiwan. Boo! Hiss! It's not like the old SouthBends that were made here back in the '40s. I'll take those old ones over a new one.
A 10 in swing is probably plenty.There are two versions of a Southbend 10 in,light and heavy.
The light has a small spindle bore.No 5c collets,no barrel through the headstock.The heavy 10 will use a 5c drawbar and has about a 1 3/8 or so bore through the spindle.
I see some so old they do not have quick change gearbox,I'd pass.
Subject to wear,and critical to thread cutting,are the half nuts.Be careful.
Old South Bend parts are available via Grizzly tools
Be aware of whether it is single phase or three phase.Phase converters are available to run a three phase machine.
The variable drive on a Clausing is great,till they wear and become loud and troublesome.Otherwise,a fine machine.
I like a 13 in Harrison.
Likely,the old South Bend is what you will find
The light has a small spindle bore.No 5c collets,no barrel through the headstock.The heavy 10 will use a 5c drawbar and has about a 1 3/8 or so bore through the spindle.
I see some so old they do not have quick change gearbox,I'd pass.
Subject to wear,and critical to thread cutting,are the half nuts.Be careful.
Old South Bend parts are available via Grizzly tools
Be aware of whether it is single phase or three phase.Phase converters are available to run a three phase machine.
The variable drive on a Clausing is great,till they wear and become loud and troublesome.Otherwise,a fine machine.
I like a 13 in Harrison.
Likely,the old South Bend is what you will find
A 10 inch swing will probably be enough providing that the spindle bore is large enough.
I have a 10x21 import lathe that I can easily and consistently turn precision work on, you just have to take into account the limitations of the machine. On a big, heavy, expensive lathe you can turn to a diameter in far fewer passes, on my little import I have to sneak up on sizes with roughing and finishing cuts. I can chamber, thread shanks and barrrels, (no bull barrels).
The best upgrade I have done to my lathe was switching over to a larger 3 phase motor and a VFD, being able to turn the work at the proper speed is a big plus IMO.
I have a 10x21 import lathe that I can easily and consistently turn precision work on, you just have to take into account the limitations of the machine. On a big, heavy, expensive lathe you can turn to a diameter in far fewer passes, on my little import I have to sneak up on sizes with roughing and finishing cuts. I can chamber, thread shanks and barrrels, (no bull barrels).
The best upgrade I have done to my lathe was switching over to a larger 3 phase motor and a VFD, being able to turn the work at the proper speed is a big plus IMO.
Lots of great old lathes out there. As others said stay away from bench mounted. Also pay particular attention to spindle bore. Monarch & Hardinge made the cadilac of manual lathes. Both tend to be a small bore. 1-1/8 to 1-3/8. You can usually get your best deal on larger swing and longer bed models because less back yard type guys want them. I have a 17x96 Cinncinatti that I paid $1500 (plus rigging) its in A+ condition. I also have a 13x36 Colchester that I paid $15k in similar condition.
Colchester, Sheldon, LeBlonde all make good quality smaller lathes that you can get for $5-$8k on the used market in good condition. Bought a HF lathe for my kid as a training/toy. It will only cut about .015 (diameter) in steel.
Colchester, Sheldon, LeBlonde all make good quality smaller lathes that you can get for $5-$8k on the used market in good condition. Bought a HF lathe for my kid as a training/toy. It will only cut about .015 (diameter) in steel.
bores and swings.
I'll have to do more homework and research because this is all Spanish to me so far. I won't claim to know more than I do but have given up the bench top idea. Bed length and size simply isn't large enough. And I would like the option of a "through chuck" if that makes sense.
I'll have to do more homework and research because this is all Spanish to me so far. I won't claim to know more than I do but have given up the bench top idea. Bed length and size simply isn't large enough. And I would like the option of a "through chuck" if that makes sense.
The "through chuck"idea is what I meant by spindle boreApprox1 3/8 in allows a 5-c collet setup,which is a very useful thing.
A taper attachment is handy
A South Bend such as this one,if the link works,is a pretty good gunsmith lathe
http://www.ebay.com/itm/HEAVY-10-SO...t=BI_Control_Systems_PLCs&hash=item4ac1e528c3
I ran one of these for years,stout,precise,rigid,excellent for threading,one of the finest small lathes ever!But maybe more than a hobby gunsmith needs.
http://www.ebay.com/itm/MONARCH-10E...001?pt=LH_DefaultDomain_0&hash=item2ec71abd51
In between,this Harrison is a good machine
http://www.ebay.com/itm/13-19-x-25-...777?pt=LH_DefaultDomain_0&hash=item4abf6e25b9
A taper attachment is handy
A South Bend such as this one,if the link works,is a pretty good gunsmith lathe
http://www.ebay.com/itm/HEAVY-10-SO...t=BI_Control_Systems_PLCs&hash=item4ac1e528c3
I ran one of these for years,stout,precise,rigid,excellent for threading,one of the finest small lathes ever!But maybe more than a hobby gunsmith needs.
http://www.ebay.com/itm/MONARCH-10E...001?pt=LH_DefaultDomain_0&hash=item2ec71abd51
In between,this Harrison is a good machine
http://www.ebay.com/itm/13-19-x-25-...777?pt=LH_DefaultDomain_0&hash=item4abf6e25b9
Last edited:
Boomer58cal
New member
My south bend was given to me by my father. It is the one his mentor had in WWII. It's a 10". It's bolted to a foot thick concrete slab so it's plenty stable.
I have never seen a horizontal lathe that had a solid headstock. Are you referring to the large bore type? Like oil field equipment?
@MattL46-- If your in the NJ area you are welcome to stop into my shop and I will give you a tour along with a quick lathe lesson. I have 9 manual lathes here. I have 2 that are getting ready for replacement and would probably be fine for your use, but they are all 3-phase.
This article might help
I don't own a lathe but always wanted to. Back when I was seriously looking I read this article. It was originally written in 1997 but it may still be of help.
Also I purchased this book from Midway & I found it most helpful in understanding things.
Of course your best resources are the DIY BR shooters & 'smithys in here!
Please keep us posted on your progress, as I'm interested in this project too!
...bug
I don't own a lathe but always wanted to. Back when I was seriously looking I read this article. It was originally written in 1997 but it may still be of help.
Code:
http://www.mermac.com/advicenew.htmlAlso I purchased this book from Midway & I found it most helpful in understanding things.
Code:
http://www.midwayusa.com/product/295571/the-complete-illustrated-guide-to-precision-rifle-barrel-fitting-book-by-john-l-hinnantPlease keep us posted on your progress, as I'm interested in this project too!
...bug
Hibc and bumble bug thank you so much for the great info. Boogie man I wish I was because I wouldn't hesitate to take you up on it. Very gracious of you. Unfortunately im way southwest of you in the plains of Oklahoma. My dad was quite a gunsmith in his day learned from his dad. But he had 4 boys and had to give it up! I'm 1/4 to blame. So he should be able to help me get started him and a brother of mine have some interest so they will be able to help with cost. I'm awful partial to american stuff but that's mostly a thing of the past...sad as that is.
There are many old lathes that would work for gun smithing. Too many people fixate on the South Bend Heavy 10, aka "10L", as it is one of the more popular "brands" of lathes in the days when we Americans made manual machines in the US. As a result, the SB "Heavy" 10L (which is anything but heavy.... it's actually a pretty light machine, just heavier than the 10K) is bid up in price in the used iron market.
Off the top of my head, here are some lathes that would suite a gunsmith if he wants to put the barrel through the headstock:
- SB Heavy 10
- SB Heavy 13 (you won't be able to do short barrels, but 24" and longer will work)
- Clausing 5913/5914
- Rockwell 11"
- Emco (NB NOT "E*n*co, but eMco, a swiss maker of machine tools) 11" lathes
- Colchester "Student"
- Logan 14x40
- Sheldon
There are others. There's actually quite a few in this size range of the old iron market.
Now, there's a huge mis-conception out there that you "must" have a lathe that is short enough through the headstock to allow you to set up a barrel in spiders on both ends in order to do anything with gunsmithing. Not true.
This whole "through the headstock" idea got going with the benchrest community in the late 80's and through the 90's. Golly, guns had been around for some time before this, no? So how did gunsmiths work on rifle barrels before some smiths started setting their barrels through the headstock?
In a steady rest, that's how.
If you give me any lathe with a good, true, long bed (40" between centers or more), I can do a barrel from a blank. That includes: chambering, fitting to the action, crowning and turning the taper/contour/cylinder. You don't have to work through the headstock of a lathe in order to do good work. When you learn how to work barrels through a steady rest, suddenly lathes anywhere from a South Bend 9" (I'd prefer a SB 9 A, if I had to deal with a SB 9 - I like quick change gearboxes) to a 17 or 18" swing beast of a lathe will work.
I don't like light machines. I own a light Taiwanese machine, but it's not my preference in a machine - it's what works in my situation. To me "light" is anything under a ton in weight. Some of my most favorite lathes come in between 4,000 and 6,000 lbs in weight. The finish on their cuts is superb, they're accurate, and cutting gun parts is so easy, the machine doesn't even know you're doing something. So don't turn up your nose at larger machines if you have the room to fit one. In "big" lathes (over 14" swing), the Cadillacs of the machine tool market in the US used to be American Pacemaker and Monarch. Unless you're ready to deal with a very heavy machine, you probably won't be able to take on one of these machines - and their prices in the used market often reflects the knowledge of machinists that these lathes were some of the very best quality ever made in the US.
Now, as to collets: 5C collets are very useful. I use them all the time. But they're hardly the only collet family out there. If you crack open a Machinery's Handbook, you'll see that there's something like two dozen families of collets out there. 5C and R8 collets are simply the last two collet families from the Grand Old Days of American Machine Tools that are still hanging on.
But unless you're a machine collector, why worry about which collet family you're going to use? You're worried about getting something done, not whether you have a historically accurate collet set to go with your lathe.
For a guy with a tight pocket, here's an idea that would serve really well:
Consider dispensing with the old collet families entirely. Make or buy a ER32 or ER40 collet holder, then buy a set of ER32 or ER40 collets and a collet nut. Making the collet holder is pretty straightforward lathe work. Making the nut isn't - which is why I recommend buying the nut.
Put the collet holder into your 4-jaw chuck, dial it in, then use collets as needed. When/if you get a mill, you can use the ER collets to hold your tools there too. You can get ER32 or ER40 collet holders that go into a R8 collet Bridgeport-style mill. ER collets grip better, hold a wider size range of parts, and are available all over the place in the modern market.
Off the top of my head, here are some lathes that would suite a gunsmith if he wants to put the barrel through the headstock:
- SB Heavy 10
- SB Heavy 13 (you won't be able to do short barrels, but 24" and longer will work)
- Clausing 5913/5914
- Rockwell 11"
- Emco (NB NOT "E*n*co, but eMco, a swiss maker of machine tools) 11" lathes
- Colchester "Student"
- Logan 14x40
- Sheldon
There are others. There's actually quite a few in this size range of the old iron market.
Now, there's a huge mis-conception out there that you "must" have a lathe that is short enough through the headstock to allow you to set up a barrel in spiders on both ends in order to do anything with gunsmithing. Not true.
This whole "through the headstock" idea got going with the benchrest community in the late 80's and through the 90's. Golly, guns had been around for some time before this, no? So how did gunsmiths work on rifle barrels before some smiths started setting their barrels through the headstock?
In a steady rest, that's how.
If you give me any lathe with a good, true, long bed (40" between centers or more), I can do a barrel from a blank. That includes: chambering, fitting to the action, crowning and turning the taper/contour/cylinder. You don't have to work through the headstock of a lathe in order to do good work. When you learn how to work barrels through a steady rest, suddenly lathes anywhere from a South Bend 9" (I'd prefer a SB 9 A, if I had to deal with a SB 9 - I like quick change gearboxes) to a 17 or 18" swing beast of a lathe will work.
I don't like light machines. I own a light Taiwanese machine, but it's not my preference in a machine - it's what works in my situation. To me "light" is anything under a ton in weight. Some of my most favorite lathes come in between 4,000 and 6,000 lbs in weight. The finish on their cuts is superb, they're accurate, and cutting gun parts is so easy, the machine doesn't even know you're doing something. So don't turn up your nose at larger machines if you have the room to fit one. In "big" lathes (over 14" swing), the Cadillacs of the machine tool market in the US used to be American Pacemaker and Monarch. Unless you're ready to deal with a very heavy machine, you probably won't be able to take on one of these machines - and their prices in the used market often reflects the knowledge of machinists that these lathes were some of the very best quality ever made in the US.
Now, as to collets: 5C collets are very useful. I use them all the time. But they're hardly the only collet family out there. If you crack open a Machinery's Handbook, you'll see that there's something like two dozen families of collets out there. 5C and R8 collets are simply the last two collet families from the Grand Old Days of American Machine Tools that are still hanging on.
But unless you're a machine collector, why worry about which collet family you're going to use? You're worried about getting something done, not whether you have a historically accurate collet set to go with your lathe.
For a guy with a tight pocket, here's an idea that would serve really well:
Consider dispensing with the old collet families entirely. Make or buy a ER32 or ER40 collet holder, then buy a set of ER32 or ER40 collets and a collet nut. Making the collet holder is pretty straightforward lathe work. Making the nut isn't - which is why I recommend buying the nut.
Put the collet holder into your 4-jaw chuck, dial it in, then use collets as needed. When/if you get a mill, you can use the ER collets to hold your tools there too. You can get ER32 or ER40 collet holders that go into a R8 collet Bridgeport-style mill. ER collets grip better, hold a wider size range of parts, and are available all over the place in the modern market.
Last edited:
Wyop very good information I'm not particular about a hollow spindle. Just a neat feature if like to have. Before I started my in depth research the only way I knew how to set up a barrel was with a long bed and a steady rest. A steady rest will be a must for whatever machine I decide on.
Collets are used for holding either tools or small work.
Let's say you wanted to make a small screw from 1/8" screw stock. Putting that into a 4-jaw chuck, dialing it in and so on gets incredibly fiddly and wastes quite a bit of time - if you're able to do it. Many larger chucks can't grab hold of very small diameter parts.
Enter collets. Let's start with the 5C collet and the South Bend 10L or similar 5C lathe (which would be 1 3/8ths through the headstock) and you want to turn some screws, pins or other small parts.
You'll pull off the 4 or 3 jaw chuck - either unscrew it or un-cam it.
This leaves you with a "naked" spindle.
You'll have a collet adaptor that slips into the spindle at the working end. You'll have a tube, into which the 5C collet can screw, that goes into the headstock from the left side. It will have a collar on it to allow the hollow shaft to spin inside the collar that trues up the tube where it goes into the headstock. They sort of look like this:
http://www.repair--parts.com/Plasti...el-collet-closer-for-monarch-10EE-partpix.jpg
While that's for a Monarch 10EE (which is a very good toolroom lathe), there are closers which are the same form for South Bend 10L's and 13's.
With some talent and time, you could make your own screw-type collet closer. Been there, done that. Look in Machinery's Handbook for the thread and size specs. You want to use 4140 alloy steel tube.
OK, so you have the tube through the headstock. You put the collet into the adaptor that you've put into the headstock. Now you put your part into the collet of the correct size (for 5C collets, this means you choose a collet that's no more than +/- 0.005 to +/- 0.008 or so away from your part size). You put your collet (with the part in it) into the adaptor in the headstock, then you start tightening the handwheel on your left until the collet engages the threads in the tube and the collet gets sucked into the adaptor in the headstock, and the collet crushes down on your part.
The beauty of collets is that if you have a good set of collets, a true spindle and adaptor, you don't have to dial anything in. The part in the collet will be within 0.001 of being dialed in. THAT is the real beauty of collets: You can put parts into them and not spend a second dialing the part into true.
There is a class of lathe that worked especially well with collets - so much so that the lathe was optimized for using collets. The Hardinge HLV-H is one such example of a lathe:
http://www.lathes.co.uk/hardinge/
The closer on the left side of that lathe could be adjusted so that you just shoved the lever to the left, the collet locked onto the part and away you went. When you were done, you'd grab the closer lever, jerk it to the right, and the part came free.
3C and 5C collets were designed to hold work, but could also hold tools. One of the things many gunsmith wanna-be's don't know is that there used to be gunsmiths that didn't own a milling machine at all. They had a milling attachment that mounted onto the compound or cross-slide of the lathe. It was basically a machinist's vise with an adjustment screw that would give you a Y-axis adjustment with a calibrated collar on the screw, you'd use your cross-slide for the X and your left/right movement of your saddle (or the compound if you turned it to parallel with the spindle) for your Z axis.
You'd put a collet into the headstock, then mount your end mill in the collet, wind it up and start milling.
5C collets are threaded on the outside, and were intended to have tube with internal threads grab the collet, so you could put long, thin workpieces into the headstock. Screwstock rods were quite commonly turned into screws like this on a lathe.
Now, R-8 collets were made for holding tools - and became "standard" for Bridgeport-type milling machines after WWII until recently. The R-8 collet has an internal thread for the drawbar on a mill to pull the collet into the spindle, so you can't put long work into the collet. It was designed to accept straight-shank end mills and such.
ER-type collets (designed in Germany since CNC machines became very common) are usually used for holding tooling in CNC machines. But they clamp onto tooling better than R-8 collets do (you can slip mills and drills in R-8 collets under heavy loads) and they clamp over a wider range of sizes than R-8's or 5C's. ER-type collets hold tools in CNC spindles under much, much more horsepower than any Bridgeport or small engine lathe can hope to develop. I've put tools into ER-40 collets in a VMC then loaded up the spindle to about 10+HP - indicated on the load meter, and the tool never slipped. R-8 collets I've had slip when I've used large diameter tooling in a Bridgeport-type mill.
A good set of 5C collets in a very close set of sizes (eg, by 32'nds of an inch) can be quite spendy. 5C collets are also available in square bores, hex bores, and so on. They're very, very useful... but for most people, a set of good 5C collets and all the associated tooling can be rather expensive - just a complete set of round hole 5C's can run over $1K from Lynden (which makes some of the best collets out there), whereas you can get into a good set of ER32 collets for a lot less money because they're much more common in modern CNC shops. If you can find used 3C/5C/16C/R8/etc collets that were made in the US, you can find bargains... but sometimes, collets get abused by their owners and used collets can be sprung, cracked or mangled on the face of collet.
How important are collets in a gunsmithing operation? Well, let's put it this way: You'd end up making something very similar to collets if you don't have them. There's just too many small parts and tools you need to grab hold of in gunsmithing. In a big machine shop, where you're working on workpieces so big you need a jib crane just to get your chuck on/off the lathe, you'll almost never see collets in operation.
5C collets are also used in "collet blocks" to hold parts in mill vises. There are square and hex collet blocks, so if you need to machine something four or six times, you just set up a mill stop on the vise, then put your workpiece (in the collet, which is held in the collet block) into the vise, you do your operation, loosen the vise, turn the block, repeat, etc.
Here's an example of a collet block for 5C's:
http://www.lyndexnikken.com/store/pc/catalog/Standard Catalog_0156_0002.jpg
Let's say you wanted to make a small screw from 1/8" screw stock. Putting that into a 4-jaw chuck, dialing it in and so on gets incredibly fiddly and wastes quite a bit of time - if you're able to do it. Many larger chucks can't grab hold of very small diameter parts.
Enter collets. Let's start with the 5C collet and the South Bend 10L or similar 5C lathe (which would be 1 3/8ths through the headstock) and you want to turn some screws, pins or other small parts.
You'll pull off the 4 or 3 jaw chuck - either unscrew it or un-cam it.
This leaves you with a "naked" spindle.
You'll have a collet adaptor that slips into the spindle at the working end. You'll have a tube, into which the 5C collet can screw, that goes into the headstock from the left side. It will have a collar on it to allow the hollow shaft to spin inside the collar that trues up the tube where it goes into the headstock. They sort of look like this:
http://www.repair--parts.com/Plasti...el-collet-closer-for-monarch-10EE-partpix.jpg
While that's for a Monarch 10EE (which is a very good toolroom lathe), there are closers which are the same form for South Bend 10L's and 13's.
With some talent and time, you could make your own screw-type collet closer. Been there, done that. Look in Machinery's Handbook for the thread and size specs. You want to use 4140 alloy steel tube.
OK, so you have the tube through the headstock. You put the collet into the adaptor that you've put into the headstock. Now you put your part into the collet of the correct size (for 5C collets, this means you choose a collet that's no more than +/- 0.005 to +/- 0.008 or so away from your part size). You put your collet (with the part in it) into the adaptor in the headstock, then you start tightening the handwheel on your left until the collet engages the threads in the tube and the collet gets sucked into the adaptor in the headstock, and the collet crushes down on your part.
The beauty of collets is that if you have a good set of collets, a true spindle and adaptor, you don't have to dial anything in. The part in the collet will be within 0.001 of being dialed in. THAT is the real beauty of collets: You can put parts into them and not spend a second dialing the part into true.
There is a class of lathe that worked especially well with collets - so much so that the lathe was optimized for using collets. The Hardinge HLV-H is one such example of a lathe:
http://www.lathes.co.uk/hardinge/
The closer on the left side of that lathe could be adjusted so that you just shoved the lever to the left, the collet locked onto the part and away you went. When you were done, you'd grab the closer lever, jerk it to the right, and the part came free.
3C and 5C collets were designed to hold work, but could also hold tools. One of the things many gunsmith wanna-be's don't know is that there used to be gunsmiths that didn't own a milling machine at all. They had a milling attachment that mounted onto the compound or cross-slide of the lathe. It was basically a machinist's vise with an adjustment screw that would give you a Y-axis adjustment with a calibrated collar on the screw, you'd use your cross-slide for the X and your left/right movement of your saddle (or the compound if you turned it to parallel with the spindle) for your Z axis.
You'd put a collet into the headstock, then mount your end mill in the collet, wind it up and start milling.
5C collets are threaded on the outside, and were intended to have tube with internal threads grab the collet, so you could put long, thin workpieces into the headstock. Screwstock rods were quite commonly turned into screws like this on a lathe.
Now, R-8 collets were made for holding tools - and became "standard" for Bridgeport-type milling machines after WWII until recently. The R-8 collet has an internal thread for the drawbar on a mill to pull the collet into the spindle, so you can't put long work into the collet. It was designed to accept straight-shank end mills and such.
ER-type collets (designed in Germany since CNC machines became very common) are usually used for holding tooling in CNC machines. But they clamp onto tooling better than R-8 collets do (you can slip mills and drills in R-8 collets under heavy loads) and they clamp over a wider range of sizes than R-8's or 5C's. ER-type collets hold tools in CNC spindles under much, much more horsepower than any Bridgeport or small engine lathe can hope to develop. I've put tools into ER-40 collets in a VMC then loaded up the spindle to about 10+HP - indicated on the load meter, and the tool never slipped. R-8 collets I've had slip when I've used large diameter tooling in a Bridgeport-type mill.
A good set of 5C collets in a very close set of sizes (eg, by 32'nds of an inch) can be quite spendy. 5C collets are also available in square bores, hex bores, and so on. They're very, very useful... but for most people, a set of good 5C collets and all the associated tooling can be rather expensive - just a complete set of round hole 5C's can run over $1K from Lynden (which makes some of the best collets out there), whereas you can get into a good set of ER32 collets for a lot less money because they're much more common in modern CNC shops. If you can find used 3C/5C/16C/R8/etc collets that were made in the US, you can find bargains... but sometimes, collets get abused by their owners and used collets can be sprung, cracked or mangled on the face of collet.
How important are collets in a gunsmithing operation? Well, let's put it this way: You'd end up making something very similar to collets if you don't have them. There's just too many small parts and tools you need to grab hold of in gunsmithing. In a big machine shop, where you're working on workpieces so big you need a jib crane just to get your chuck on/off the lathe, you'll almost never see collets in operation.
5C collets are also used in "collet blocks" to hold parts in mill vises. There are square and hex collet blocks, so if you need to machine something four or six times, you just set up a mill stop on the vise, then put your workpiece (in the collet, which is held in the collet block) into the vise, you do your operation, loosen the vise, turn the block, repeat, etc.
Here's an example of a collet block for 5C's:
http://www.lyndexnikken.com/store/pc/catalog/Standard Catalog_0156_0002.jpg