Desktop Lathe recommendations and method suggestions for shaping ship masts

[paul ron]

I have that very lathe ,and can say I like it better than my old Unimat.

id love to own an old unimat. i see them occasionally for sale but they are asking rediculuos prices.

ive used my delta floor drill press as a lathe. i made a live center and tool rest. its ok for occasional small jobs, but having a lathe is a better solution.

whatever you get, just be sure its a sturdy machine.

 

[Bob Cleek]

I'd love to own an old unimat. i see them occasionally for sale but they are asking ridiculous prices.

They always were expensive and now that they've been out of production for decades, they've become a cult item. They were, in their day, the ultimate modeler's machine tool. Gerald Wingrove's book, The Techniques of Ship Modeling, which is a great read, albeit a bit dated today, inspired thousands of ship modelers to buy one half a century ago. Wingrove did all his amazing modeling on a Unimat SL/SD, including his famous metal miniature motorcars. Sherline and Taig fill the market niche these days, but at a far greater cost because you have to buy separate lathes and milling machines to do what the single Unimat can. While the basic Unimat SL/SD model in good shape can be had for six or seven hundred bucks, it's the tooling and attachments that have become hugely expensive. Still, the used Unimats are less that the current equivalent machinery. The basic Unimat SL/SD is a combination lathe, drill press, and milling machine. From there, if you can find and afford them, there are attachments to turn it into a mini-table saw, planer, scroll saw, jig saw, disk sander, threading lathe, a power feed option, extended bed, jeweler's spindle for really small work, a bench grinder, and polisher, a flex-shaft attachment, and so on. Then there's usual range of tooling: three- and four-jaw chucks, live centers, tail stock Jacobs chucks, center rest, collet holder and collets, etc., etc. I have no idea what a complete Unimat SL/SD "system" would be worth today.

The thing I can't figure out is why somebody hasn't started making them again. It seems to me that either the Indians or the Chinese could turn out the whole Unimat system with enough meat left on the bone to make a healthy profit. I doubt there are any patents that would prevent it. There's nothing unusual about the mechanics of the thing. If you get the chance to get your hands on one, grab it!

 

[paul ron]

right on bob. i had an oportunity to buy a new one back in the day but i was in an appartment then. once i got into my house and established a nice workshop in the basement i just got a nice wood working lathe instead. i made new balesters for my stairs and turned bowls and candle sticks... but the unimat remained on my wish list. i worked in a nyc hospital and being friendly with the maintenance shops, i had access to a real metal lathe the size of a car. so i had the best of the best at my fingertips. the unimat lust fell the wayside. but once retired 16 years ago, the unimat has been nagging at me n kicking myself in the butt ever since thinking how relatively cheap i could have gotten one new. also the fact it has so many transformations makes it the amazing all in one complete shop machine for the hobbiest home shop.

btw my full sized lathe makes a nice shelf for crap in my shop now. i rarely need such a large lathe anymore.

still kicking myself!

 

[Roger Pellett]

Unlike Paul, I’m not kicking myself.

Very early in my career, after leaving the navy, the Ohio State Legislature voted a cash award to those who had served in the military during the Vietnam War. While my hazardous duty during four years of naval service was limited to a week’s ride, underwater on a nuclear submarine I still qualified and received the money. It was enough to buy a Unimat lathe.

Before spending the money, I saw an ad in our local paper for a used metal lathe; cost $125. It was an old sears Duncan brand lathe. I bought it instead. The rest of Ohio’s money went elsewhere. I got the lathe up and running and enjoyed using it for many years.

Years later, the Company moved me from Ohio to Duluth, MN and the promotion meant that I could shop for a new lathe. I don’t remember why I passed on a Unimat; perhaps it was no longer made. Anyway, I bought a Sherline. I have not been sorry. It is a rugged well made machine capable of withstanding my mishaps. I actually use the milling column more, but I do turn brass parts. As I learn by making mistakes, it’s a better choice for me than a Unimat.

Roger

 

[Philski]

If you want something versatile and inexpensive (at the possible loss of perfection every time) buy a pillar drill (about £100). Make sure it has a table that can be raised and lowered. The dowel you want to turn is a cut a bit (1") oversize in length and mounted in the chuck. The bottom end of the dowel is centered firmly on a sharp pin (small hardened steel masonry nails are good) which is fixed in a small vice fixed to the table. Make sure it is all plumb (vertical) That way both ends of the dowl are fixed, and you can sand the taper more readily. This will also accommodate dowels up to 12" long.

The nice things are - a pillar drill is not really a space or a money hog, and you can actually use it for drilling, too.

The main reason I use a lathe is because it is versatile, robust and available. I can use it for far more than ship building. I initially purchased it to turn spindles for a rocking horse I built for my grand daughter. Of course lathes, wood and metal require more TOOLS! (And we all need more don't we)

 

[Bob Cleek]

Roger, I started with my dad's Craftsman wood turning lathe, bought new with turning chisels for $50 in 1950. About twenty years ago, I bought an Atlas/Craftsman 12 x 42 from the widow of a master machinist who had bought it new and babied it for all the years he had it. It came with just about every bit of tooling and attachment they ever made for the thing, plus a bunch of machinists' tools, most Starrett or Brown and Sharpe. She wanted $750 USD for it and that was the fastest I ever got $750 USD out of my pocket. Then, about ten years ago, I mentioned the Unimat lathes in a conversation and a fellow says, "My dad had one when we lived in England. I've never touched it because it's got a motor that runs on British 220 VAC. You can have it, if you want it." Well, that was the most expensive freebie tool I've picked up in a long while. I must have put about $1,500 USD rebuilding what turned out to be a hard-used and abused Unimat. Of course, everything had to be found on eBay at pirate's prices (which have only increased since then.) I put a later model continuous duty motor on it. (The early motors were limited duty... about 8 min. before you have to quit and let them cool off.) Then I replaced the bent lead screw and did a rebuild on the headstock with new bearings. Then, began the hunt for tooling and it got really expensive. I took a pass on the threading tooling, the power feed, and the collets because that was all covered by my Atlas/Craftsman lathe. I skipped the scroll saw and the mini-table saw because I already had a scroll saw and a Byrnes' saw. Still, the little bits and pieces all added up. If I had needed a smaller lathe to begin with, I would have definitely gone with the Sherline. Owning the Atlas/Craftsman had taught me the problems with finding parts and tooling for out of production machines. I do have to admit I got bit by the collecting bug when I rebuilt the Unimat. There's nothing I can do on my 3" Unimat that I can't do on my 12" Atlas, but the Unimat is more fun to use on the small stuff.

 

[Roger Pellett]

I used to drool over those Atlas lathes. When I was shopping to replace my old sears lathe a local dealer sold Jet lathes; a Taiwanese clone of the Atlas. Having at the time some interest in gunsmithing, I was tempted. I now realize that I only knew enough about gunsmithing and machining to be dangerous to myself and others others, and shooting is limited to punching a few holes in a paper target with a 22 rifle maybe once or twice a year. In hindsight. For me, the Sherline was the right choice.

Roger

 

[Allegheny]

Been there, done that, got the tee shirt. A wood turning lathe will spin a dowel, but without elaborate accessories (read: expensive or time-consuming if shop-made) turning a taper freehand with a chisel is little better than the tried-and-true sandpaper technique (which is pretty good once you get the hang of it.) The bottom line is that accuracy is dependent upon "eyeballing."

A machinist's lathe is a wonderful tool to have, but they are very expensive and the tooling to do accurate tapering on one is also quite costly, assuming one can even find a suitable tapering attachment. Such a lathe will also require a capacity sufficient to accommodate the longest spar you intend to taper. The ubiquitous Sieg-manufactured "7 by X" Chinese mini-lathes only provide a nominal taper length of between seven and fourteen inches, depending upon the model, and, after allowing for mounting tooling such as face plates, chucks, and/or live centers, you will only have perhaps five to twelve inches of taper length available, depending upon the lathe's bed length. A minimum 12"x 36" benchtop lathe would be the smallest capable of really doing the full range of spars modelers would need. You would also want to have a hollow headstock with a hole large enough to pass longer workpieces through the headstock spindle, if required. A 12" swing will give you that, but the 7" swing lathes may not, and I'm unsure whether they even have hollow headstock spindles.

The lathe compound can also be used to taper (if the lathe has a compound,) but the length of a taper using the compound is limited to the size of the lathe and a spar of any length will probably require a lathe so large that cost would be prohibitive for most of us.

Alternatively, the tailstock can be offset to achieve a taper, but this involves tedious setting up. There is an attachment available, however, that permits offsetting the tailstock end of the workpiece. It has a fine adjustment and a ruled gauge which provides an easily adjusted setup without having to offset the tailstock itself. This bit of tooling is mounted on a #2 or #3 Morse taper post for mounting on the tailstock, so it will only work on a lathe with a MT2 or MT3 tailstock taper, meaning something bigger than the "7 by's." Its size will cost you a couple of inches in maximum taper length, as well.

View attachment 530442

Amazon.com

Regardless of whether one uses a dedicated tapering jig, a compound, or offsets the tailstock or the workpiece with a device such as illustrated above, all of which are primarily intended for turning metals and other rigid materials, there is a potential problem with deflection of the workpiece when turning thin wooden spars. The pressure of the cutting tool against the wooden piece can bend the wood and destroy the accuracy of the taper machining, so great care needs to be exercised to take very fine cuts to avoid this. I am at a loss to know how, in a tapering application, a standard traveling backrest might be used to prevent deflection error when machining long thin pieces because not only would the backrest have to move together with the cutting tool on the X axis, but it would have to move closer to the workpiece on the Y axis as the piece thins as the cutting tool runs down the length of the workpiece cutting the taper.

The only solution I know of to negate deflection error in a taper turning of thin stock is to do the cutting with a tool post grinder or a rotary tool with a suitable end mill or abrasive bit mounted on the cross-slide. A dedicated tool post grinder, which is the tool actually designed for the job, even for a 12" swing lathe, with set you back at least $1,500 USD with freight. Together with the 12" lathe, that's way beyond my modeling credit card limits. (See: https://www.grizzly.com/products/grizzly-3-4-hp-tool-post-grinder/t27400?msclkid=01429c33e397112aaf78f458ec340d7a&utm_source=bing&utm_medium=cpc&utm_campaign=[ADL] [PLA] [Shopping] - All Products&utm_term=4586063006215776&utm_content=All Products&adlclid=01429c33e397112aaf78f458ec340d7a)

It is possible, however, to mount an end mill or abrasive bit in a rotary tool, be it a "Dremel," or a flex-shaft handpiece, to do the cutting. With the rotary tool mounted on the tool post, the cut will be done by the revolving rotary tool bit and not by the stationary lathe cutting tool that requires greater pressure against the workpiece. The rotary tool only has to present the cutting or abrasive face of the bit to the workpiece at the level of the workpiece. It doesn't matter how you mount the rotary tool to the tool post. A holder can easily be shop made that has the same mounting parameters of your lathe's tool holder so that the rotary tool is held in the same position as a lathe tool, or you can perhaps (I didn't check the measurements) even buy one for twelve bucks on Amazon.

View attachment 530451

Rotary tool as mounted in Aloris-style quick-change tool holder:
View attachment 530452
(See: https://www.amazon.com/JMSMSH-Lathe...&pd_rd_r=9e77b950-79ef-4b4c-b9fb-b0e40dd84877)

Now, if all you want to do is taper spars, you don't need a machinist's lathe to do the same method just previously described. You can make your own quick and dirty spar "lathe" powered by a drill motor and your own "tool post grinder" using your Dremel mototool or flex-shaft handpiece.

1. Take two suitably sized planks of wood slightly longer than the longest spar you want to make and as wide as you think you'll need given the rest of these "instructions." One will be your "lathe bed" and the other will be your "taper jig."

2. Provide for the attachment of a drill motor at the left-hand end of your "lathe bed." Build a little cradle for it and clamp it with a "jubilee" hose clamp or whatever. The attachment must be rigid and secure. This will be your "headstock."

3. Screw an upright to the right-hand end of your "lathe bed to serve as your fixed "tail stock." Insert a nail in it precisely aligned with the straight forward long edge of your "lathe bed" and at the exact same height at the center line of your drill chuck with the nail point extending out a bit through the upright pointing towards the drill motor. (If the nail point isn't rounded, file it round on the point sides.) This nail point will be the center point on your lathe tailstock.

This, then, is your "lathe."

4. Take the other flat piece of wood and either rout a square slot down the center of its length precisely parallel to the sides of the piece of wood or fasten a batten down the center of its length in the same fashion. This is your "taper jig."

5. Place the "taper jig" lengthwise abutting the length of your "lathe" with both "face up" (flat faces on the bottoms) and install a hinge at the right hand ends of the "lathe bed" and the "taper jig" such that the two are hinged to open in scissors fashion at the right-hand (tailstock) end of the two pieces.

6. Take a block of wood and either tack a short batten to the bottom or rout a square groove in the bottom to match either the groove or the batten on the "taper jig" such that the block of wood will slide the length of the "taper jig" from end to end without any "slop" to allow it to wobble in the slot or on the batten on the "taper jig."

6. Fashion a method of securing your rotary tool or flex-shaft handpiece to the top of the sliding block of wood such that the center line of the rotary tool or flex-shaft handpiece spindle is at the same height as the tail stock pin and the center line of the drill motor chuck. Here, again, some sort of a cradle and a "jubilee" hose clamp should do the trick. The attachment must be rigid and secure.

7. Fashion a mechanism which will permit adjusting and setting the distance the "scissors" joint angle between the "lathe bed" and "taper jig" will open. An upright eye screw into each piece of wood at the right hand end of the joint between the two with a suitably long threaded bolt with nuts to adjust and hold the setting of the angle should suffice.

To operate, set the angle between the "lathe bed" and the "taper jig" to the same angle as the taper on your spar that you desire. Drill a small hole in the exact center of your your dowel workpiece end to receive the "tailstock nail center" and mount the dowel between the drill motor chuck and the "tailstock nail center" with the nail point in the hole in the end of the dowel. (A dab of heavy grease or Vaseline petroleum jelly for lubrication of the nail point may be required to avoid burning the nail hole in the end of the dowel.) Then adjust the end mill or abrasive bit on your rotary tool or flex-shaft handpiece to contact the right hand (tailstock) end of the dowel. Turn on the drill motor to slowly rotate the dowel. The drill motor does not have to turn the workpiece very fast. The slower the better, to minimize friction on the "tailstock nail center" and the dowel. Turn on the rotary tool or flex-shaft handpiece and move it along the length of the "taper jig."

You will have to allow sufficient extra length of your dowel so you can cut your finished spar to length at the exact diameter of the narrow end. It will take some measuring and trial and error to set up your taper angle exactly, but once set up, the taper should remain the same for multiple spars to be turned out. For yards which taper from the middle outboard, do one half and then flip the workpiece to do the other. Remember, the end mill or abrasive bit or disk on the rotary tool does the work of removing the material. The "lathe" only turns it to make the shaping even. Let the tool do the work. Don't force it.

Of course, refinements can be added, such as a protractor angle gauge to determine angle settings if you want to do the math to calculate the taper angle you need and keep a record for future reference instead of fiddling with trial and error sizing test runs and measurements whenever it's used. (See:

WARNING: HEADACHE RISK! You may have slept through this class in high school thinking, "What will I ever need to know this for?)

This tapering lathe should, for next to nothing out of a modeler's pocket, repeatedly turn out perfectly fair and straight tapers.

@Bob Cleek
By any chance do you have a set of photos or a link to a video which shows what you've described above. Thanks!

 

[Signet]

The suggestions of dowel-makers are good, but I think trance is looking for an easier and more accurate method to produce the slight tapers required for masts and spars. It would be possible to use various dowel sizes to "step" a longer mast, then sand by hand, but that's still guesswork. I've used my hobby table saw to cut rings in dowels to a depth that indicates the correct diameter at that point. But it's still difficult to get an accurate taper between each step.

A wood lathe will rotate a long length, but making precise tapers will usually involve just sanding and checking, not much different than doing it with a drill, IMHO. I have the 250 Proxxon lathe, but have found that the drill method works better. Theoretically, a metal lathe would be the way to go, as you can precisely control the the depth of cut and therefore taper. But as mentioned above, deflection of the dowel makes it more difficult than you'd like. And unless you buy a larger metal lathe (VERY expensive), the between-centers distance is not enough for some 1/48 scale masts (although most have hollow spindles that helps accommodate longer pieces).

I'm not sure there is a really good solution to the problem. Every one I know of has problems or limitations, usually requiring guesswork or constant monitoring of diameter along the length. I've used the dowel-in-drill along with a small and large belt sander, and it's worked well for me, but of course requires constant diameter checking. But at least my workbench doesn't have a 100+ pound lathe I have to move.

 

[aferox]

I use an old watchmaker lathe I got on eBay. It was pretty inexpensive at the time and included the motor and a foot pedal. It is quite compact. The end can be removed and I can therefore turn dowels of any length - for long masts and spars I support the end of the dowel with a glove and use sanding tools. I can control the speed easily. Getting the shape precise would require careful measurement. It is also in my opinion a beautiful piece of equipment!

 

[Bob Cleek]

By any chance do you have a set of photos or a link to a video which shows what you've described above. Thanks!

I saw the taper turning jig I described in the post online some time ago, but for the life of me I can't find it now.
This video shows the mechanical principle in practice on a standard lathe. They use a router or laminate trimmer for the milling tool. For the DIY version, a drill motor turning a dowel between two uprights suffices for the "lathe." The dowel doesn't need to be turning very fast at all. Note in this video that the taper is defined by the angle cut in the plank which the base of the router/laminate trimmer/rotary tool rides against. In the video, the taper angle is fixed. In my description, the angle was adjustable. If you have a standard scissors-style table saw taper jig, that would be an excellent way to have an adjustable angle "definer."

Grizzly T32311 - Taper Jig - Grizzly Industrial, Inc.

<h1>Grizzly T32311 Taper Jig</h1> <h2>Make accurate cuts and sand edges easily with this jig.</h2> <p>The T32311 Taper Jig lets you control your workpiece when making tapered or angled cuts on a table or miter saw.</p> <p>Constructed from sturdy aluminum, the jig adjusts between 1°–15° or 3" per...

www.grizzly.com

Below is another version of the same mechanical setup. I'm not sure what he's using for the rotary cutter, though.

This last video is another version of the same principle applied for turning straight dowels on a table saw. Let me say at the outset that this is an excellent setup, except for the fact that it scares the hell out of me from a safety standpoint. It would be less scary on a mini table saw, such as a Byrnes, but still dangerous. One would have to engineer it so that there were stops on the slides to prevent the blade from hitting the drill motor at the end of the work, and so on. This arrangement is obviously very accurate. In order to modify it for tapering, a means of lifting the base of the sled one half the difference between the maximum and minimum diameters of the tapered workpiece's ends would have to be devised. Perhaps a couple of threaded bolts run through nuts epoxied into the base at the drill motor end so, passing through the base, they would raise the base.

All these examples are intended as food for thought. The basic principle is the same: using rotation on two axis, the "lathe" and the "rotary tool," permits the coordinated simultaneous shaping of the workpiece when the rotary tool removes material on a taper across the X-axis while the Y-axis turns.
Finally, having come across the rotary tool toolpost holder mentioned in my earlier post, I purchased one for $13.00 on Amazon. It is indeed threaded for the Dremel moto-tools. Even if one doesn't have a sufficiently large lathe toolpost to hold it, the thing is a really handy item because it permits the moto-tool to be mounted in a vise or clamped in some other fashion to permit its stationary use, freeing both hands for the workpiece.

JMSMSH Lathe Tool Post Grinder Attachment 3/4-12 Thread - Amazon.com

JMSMSH Lathe Tool Post Grinder Attachment 3/4-12 Thread - Amazon.com

www.amazon.com

 

[Bob Cleek]

The suggestions of dowel-makers are good, but I think trance is looking for an easier and more accurate method to produce the slight tapers required for masts and spars. It would be possible to use various dowel sizes to "step" a longer mast, then sand by hand, but that's still guesswork. I've used my hobby table saw to cut rings in dowels to a depth that indicates the correct diameter at that point. But it's still difficult to get an accurate taper between each step.

A wood lathe will rotate a long length, but making precise tapers will usually involve just sanding and checking, not much different than doing it with a drill, IMHO. I have the 250 Proxxon lathe, but have found that the drill method works better. Theoretically, a metal lathe would be the way to go, as you can precisely control the the depth of cut and therefore taper. But as mentioned above, deflection of the dowel makes it more difficult than you'd like. And unless you buy a larger metal lathe (VERY expensive), the between-centers distance is not enough for some 1/48 scale masts (although most have hollow spindles that helps accommodate longer pieces).

I'm not sure there is a really good solution to the problem. Every one I know of has problems or limitations, usually requiring guesswork or constant monitoring of diameter along the length. I've used the dowel-in-drill along with a small and large belt sander, and it's worked well for me, but of course requires constant diameter checking. But at least my workbench doesn't have a 100+ pound lathe I have to move.

It's actually not that difficult once the mechanics of taper turning are understood. It's like patting your head and rubbing your stomach at the same time. You need a turning workpiece and a rotary cutter moving the length of the workpiece at the angle of the taper. If the taper fence is straight, your taper will be straight.

If one is tapering with sandpaper as most of us do or have done, gluing the sandpaper to a stiff batten and applying the straight stiff batten "sanding block" on the flat of the workpiece will avoid any "waves" in the taper because the cutting block will be flat and straight.

You may want to take a look on YouTube at the many variations, some quite fancy, of the table saw tapering jigs. That approach may well be a good solution, given that you have a mini table saw.

 

[Allegheny]

I saw the taper turning jig I described in the post online some time ago, but for the life of me I can't find it now.
This video shows the mechanical principle in practice on a standard lathe. They use a router or laminate trimmer for the milling tool. For the DIY version, a drill motor turning a dowel between two uprights suffices for the "lathe." The dowel doesn't need to be turning very fast at all. Note in this video that the taper is defined by the angle cut in the plank which the base of the router/laminate trimmer/rotary tool rides against. In the video, the taper angle is fixed. In my description, the angle was adjustable. If you have a standard scissors-style table saw taper jig, that would be an excellent way to have an adjustable angle "definer."

View attachment 531515

Grizzly T32311 - Taper Jig - Grizzly Industrial, Inc.

<h1>Grizzly T32311 Taper Jig</h1> <h2>Make accurate cuts and sand edges easily with this jig.</h2> <p>The T32311 Taper Jig lets you control your workpiece when making tapered or angled cuts on a table or miter saw.</p> <p>Constructed from sturdy aluminum, the jig adjusts between 1°–15° or 3" per...

www.grizzly.com

Below is another version of the same mechanical setup. I'm not sure what he's using for the rotary cutter, though.

This last video is another version of the same principle applied for turning straight dowels on a table saw. Let me say at the outset that this is an excellent setup, except for the fact that it scares the hell out of me from a safety standpoint. It would be less scary on a mini table saw, such as a Byrnes, but still dangerous. One would have to engineer it so that there were stops on the slides to prevent the blade from hitting the drill motor at the end of the work, and so on. This arrangement is obviously very accurate. In order to modify it for tapering, a means of lifting the base of the sled one half the difference between the maximum and minimum diameters of the tapered workpiece's ends would have to be devised. Perhaps a couple of threaded bolts run through nuts epoxied into the base at the drill motor end so, passing through the base, they would raise the base.

All these examples are intended as food for thought. The basic principle is the same: using rotation on two axis, the "lathe" and the "rotary tool," permits the coordinated simultaneous shaping of the workpiece when the rotary tool removes material on a taper across the X-axis while the Y-axis turns.
Finally, having come across the rotary tool toolpost holder mentioned in my earlier post, I purchased one for $13.00 on Amazon. It is indeed threaded for the Dremel moto-tools. Even if one doesn't have a sufficiently large lathe toolpost to hold it, the thing is a really handy item because it permits the moto-tool to be mounted in a vise or clamped in some other fashion to permit its stationary use, freeing both hands for the workpiece.

View attachment 531517

JMSMSH Lathe Tool Post Grinder Attachment 3/4-12 Thread - Amazon.com

JMSMSH Lathe Tool Post Grinder Attachment 3/4-12 Thread - Amazon.com

www.amazon.com

@Bob Cleek
Thank you for posting these videos and additional explanations.

I am in full agreement, that the table saw method is simply asking for trouble and quite dangerous.
Anything could happen during that operation causing the rotating blade to catch and break, sending piece's of it at the operator.

Do you happen to have a photo or video of the rotary tool toolpost holder in use?
Simply looking at it attached to the Dremel, doesn't convey to me how it works, or is it just me as it is not clicking as they say!

 

[Bob Cleek]

Simply looking at it attached to the Dremel, doesn't convey to me how it works, or is it just me as it is not clicking as they say!

Sorry. I searched all over and couldn't find a picture of it mounted on a tool post. I'll just have to take the long way around and explain it from the beginning because it looks like we're talking basic introduction to lathe operation here. These days fewer and fewer kids take shop class. Not to worry. Nobody's born a machinist and I'm no machinist either. I'm just old, read books, and know stuff.

Machinists' lathes use small cutting bits ground to shape for various cutting purposes:

These bits are mounted in tool bit holders which hold the bits firmly. The cutting bit is inserted through the square hole in the tool bit holder and made fast with a set screw. There are different types of tool bit holders for different applications. Below is a straight tool bit holder holding a carbide cutting bit. They commonly come in right, left, and straight, plus specialty ones to hold parting tools for cutting off workpieces on the lathe or boring bars to turn inside a hollow in a workpiece, and so on.

Tool bit holders are mounted on a tool post attached to the lathes' cross slide which moves on the X and Y cutting axes of the lathe. There are various styles of tool posts. The most common are the older lantern-style tool post and the more modern quick-change tool post. The lantern-style tool post has a slot cut in the shaft of upright post through which the tool bit holder slides. Beneath the tool bit holder is a half-moon shaped loose key which permits the tool bit holder to be raised or lowered at an angle so as to be presented to the workpiece at the desired angle. The height of the tool bit holder can also adjusted using shims placed through the "lantern's" slot beneath the tool bit holder.

The quick-change tool post holds up to four tool bit holders that are mounted in quick-change tool post in a variety of ways depending upon the tool post's design. Some tool post have simple slots on the sides into which the tool post holders (or on small lathes, even just the bits alone) are placed, while others, called "wedge type," have dovetailed blocks that hold the cutting bit holders and slide onto the four sides of the tool post. The quick-change tool post has a quick-release lever that permits the rotation of the tool bit holders without having to change their original height and depth settings each time he wants to change bits while cutting on a workpiece. (E.g., When turning the diameter of a bar to size for threading it and then cutting the threads on the bar which requires differently shaped cutting bits.) This saves the professional operator in a production environment a lot of set up time, which is money, but is not as essential to the hobbyist. Below is a wedge-type two bit quick-change tool post with one cutting bit holder mounted on the quick-change tool post block and four other cutting bit holders of various types next to it.


The rotary tool holder is just another type of cutting bit holder, or to be more specific, with a rotary tool, it would be classified as a tool post grinder. Below is a picture of the rotary tool holder holding a Dremel moto-tool and mounted in a wedge-type quick-change tool post mounting block as described above. The mounting block isn't mounted on the quick-change tool post though.



As the name implies, a tool post holds any tool one might want to use to do work on the lathe. In the instance of the Dremel, it would be a light-duty rotary tool, to be sure, but for wood work that's not a concern. With your Dremel mounted in the tool post of your lathe, you can do anything a Dremel does, including for our purposes milling, grinding and drilling, and be able to control the Dremel with the lathe's cross slide, yielding accuracy to .001". For instance, as explained, with the tailstock offset, tapers the length of the lathe bed's capacity can be turned, or, with the workpiece mounted on the headstock, a perfectly aligned and perpendicular row of pin rail holes can be drilled or, if your headstock has a dividing head feature, you can drill perfectly placed spoke holes for a ship's wheel. With the X-Y mobility provided by the lathe's cross slide and a Dremel tool mounted on the tool post, you have a basic horizontal milling machine limited only by the power of the Dremel tool.

 

[Short John Bronze]

A while ago I bought a Mantua lathe. It was useless and the power pack failed after relatively little use. The only useful bit was the set of centring bushes used to steady the tail end of a spar on the lathe. These can be bought separately and are worth having. As I have commented elsewhere: kit manufacturers should stick to making kits and leave toolmaking to others. Other examples include ratline "loom-a-line", keel clamps and pin pushers.
I subsequently bought a small Proxxon lathe with which I am very satisfied. It came with a set of collets for the drive end. I replaced these with a three jaw chuck since the collets are not very convenient at different points along a tapered spar.. The photo below shows the lathe being used in conjunction with a Mantua tail bush