Stupid idea for lathe attachment

wrote:
I have not doee this, but if I were to do so I would machine the adapter where it contacts the rear of the spindle with a taper. Not a
taper that will hold by itself, but one to center the adapter. And I would hawe a threaded section at the other end of the adapter. And use a nut to put a little tension on the adapter. That way you are not depending on the lathe chuck to hold the adapter. Probably not needed, but it is what I would do.
Dan =================I adapted a larger lathe's longer 5C collet closer tube to mine by making a brass bushing that is a light press fit in the end of the spindle and a close running fit on the tube. A shaft clamp serves as the thrust-bearing flange on the collet closer. You could make a similar steel collar that presses onto the shaft and is retained from sliding by the disc, and turn the outside to a snug or tapered fit into the spindle like Dan suggested.
Threaded rod works well for shafts that require short built-up areas of larger diameter. Jam two nuts together very tightly and turn them to the shape you want. jsw
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On 1/23/2014 10:44 AM, snipped-for-privacy@krl.org wrote:

Very astute observation!
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I've chucked up all kinds of wild things on my mini lathe in a pinch. Its always handy to have a horizontal motorized spinny thing in a pinch, but I would have some concern about abrasive grit from the sanding disc getting into the works of the lathe or even on the ways.
That being said, I kinda feel the same way as others about belt vs disc. I have two combo machines and I use the belt parts all the time, but hardly ever use the disc. I do have a tapering operation I do on one of them, but I have seriously considered converting the other over to a buffing wheel with a mandrel.
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    My first question is "can your lathe produce sufficient speed for a sanding disc to work well?". It looks as though your maximum RPM is 2200. Normally, the speeds are significantly higher. Is that 12 inch diameter? I see a '?' with my system where I would expect a '"' for inches. Did you compose this with a web browser? On Yahoo, I suspect so. Spell out units if using a web browser, as they tend to install weird characters which won't work with a plain text newsreader or e-mail client.
    Second -- how are you going to keep the sanding dust from rapidly abrading the ways of the lathe? I would put a disc sander as far as possible away from the lathe or any other precision machine tools. The grit from the sanding disc is *very* bad for the ways.
    And -- another safety point brought on by your photo of the lathe itself. *Never* leave the chuck key in the chuck -- even just for a photograph. If you hit the power switch, that chuck key gets thrown at a rather impressive velocity -- assuming that it does not simply slam into the ways of the lathe, damaging them.

    Is the lathe large enough to turn a 12 inch disk of aluminum? You'll have to saw it to something a bit oversized and turn it down.
    Also -- does it have the horsepower to proerly turn a 12 inch sanding disc at the maximum speed which it can achieve.
    Anyway -- I would turn a plug which would just barely fit into the open end of the spindle, then drill most of the way through and tap for a large setscrew (say 1/2 inch or so (or 13 mm or so), with a cone point), and then using a hacksaw or bandsaw if you don't have a milling machine, cut through the diameter on the inside end twice -- the second at 90 degrees to the first. At this point, when you run the setscrew into the center it will eventually hit the bottom of the drill hole and expand the plug to grip it firmly into the spindle.
    To this you will bolt your 12 inch disk. (Actually -- do this bolting before you turn the disk to diameter, so it will be concentric.

    If you punch a hole in the center of the sanding disc (which is moving too slowly to be of use sanding anyway) you can reach through there with the Allen (hex) key to loosen the setscrew and pull off the disc.

    Again -- I would not put sanding operations this close to the precision machine surfaces.
    Better to go ahead and make the disc and hub (without the expanding split grip I described above) and get a used electric motor of adequate size and bore the hub to slip on the end of the motor shaft. Get at least a 3600 RPM (really marked something like 3450 RPM or so) and I think at least a 1/2 HP motor for that large a disc -- and more likely a 1 HP motor. (In Germany, probably marked in KW instead of HP, figure about 0.750 KW is about one HP.) Sorry for the inch figures, but I *think* you used inches for the diameter of the sanding disc, anyway, even though the ID of the spindle is just slightly over 1" (25.4 mm). :-)
    If you can't get a motor faster than about 1750 RPM, then plan to add a pair of pulleys and a belt to increase the speed. Mount the motor below a workbench, and the disc above it, so the weight of the motor can put tension on the belt.
    Drill the hub underized, and use a boring bar to enlarge to a slip fit on the motor shaft -- a drill bit will typically be oversized.

    Sorry! Already typed the one about the chuck key. And I could not let that one go unremarked, anyway.

    But you *do* have to worry about abrading the accuracy out of the bed.

    Good Luck,         DoN.
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Good points. The machine is 750 watts, and yes, 2200 rpm max. I can turn a max of 14.5cm radius, so the disc could be up to 11.4 in. I have a guy near by with a small shop and a bigger lathe, however. The standard disc size he re is 300mm, or 11.8 in.

I agree that having the disc on the chuck side is a bad idea, but if I moun t it to the back, I don't see so much dust hitting the weighs.

Yeah, I have a bad habit of doing this. Thanks!

Good Idea!

sc.

o
At this point I would just break down and buy a sander. Now that I think ab out it, by the time I add up the hours and Euros to do any of this it seems to not pay off. I can get a lower end machine for about $240. It's just th at it would be so cool to have one sticking off of the back of the lathe, s aving a lot of space.
Thanks Don, I used to post as Robobass when I had a shop in Brooklyn back i n the '90's. Not many of the old guard seem to still be around! I've been w ithout toys since I went overseas 12 years ago, and am now putting together a proper shop once again.

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At this point I would just break down and buy a sander. Now that I think about it, by the time I add up the hours and Euros to do any of this it seems to not pay off. I can get a lower end machine for about $240. It's just that it would be so cool to have one sticking off of the back of the lathe, saving a lot of space.
================ I Googled "Bandschleifer preisvergleich" and see what you mean about their cost: http://www.idealo.de/preisvergleich/ProductCategory/3706F400057.html ;jsessionidQn_wGD-Fp_
The Westfalia MD150 looks decent for wood and the Scheppach 700 for metal or curved wood edges. I have a similar Delta (minus the "Teller") with a 1" belt that I use more than the wider one, mostly for deburring and rounding cut metal edges with the more flexible unsupported area above the platen.
The Guede, Ferm and Berlan resemble the Chinese imports sold here for $50. They are a lot better than nothing, though a 350W motor isn't really adequate for more than delicate finishing.
You do need some sort of Staubfaenger unless you work outdoors, to keep the finer airborne grit off the lathe. Even wood sawdust can quickly cause rust if it's damp.
jsw
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JSW,
I already have the Westfalia MD150, or at least a version which I got cheap from an Aldi type store. 2 inch wide belt. Very useful. And still works we ll after 10 years regular use! I couldn't pin down your other suggestions, but "Ferm" is a brand which was sold through the now defunct "Max Bahr". B ased on my experience with their biscuit joiner, I would never buy anything with this mark. I think that it is also true in the USA that the machines sold in the big box stores are intentionally made crappy. I don't get it. D o the big retailers want to frustrate you and force you to hire contractors ? It's sort of like restaurants. In Europe, at least, the closer you are to a major train hub, the worse the food is. I want to ask sometimes, "would it have cost you any more money to serve me a pizza which didn't taste like poop?" I just don't get it...
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JSW,
I already have the Westfalia MD150, or at least a version which I got cheap from an Aldi type store. 2 inch wide belt. Very useful. And still works well after 10 years regular use! I couldn't pin down your other suggestions, but "Ferm" is a brand which was sold through the now defunct "Max Bahr". Based on my experience with their biscuit joiner, I would never buy anything with this mark. I think that it is also true in the USA that the machines sold in the big box stores are intentionally made crappy. I don't get it. Do the big retailers want to frustrate you and force you to hire contractors? It's sort of like restaurants. In Europe, at least, the closer you are to a major train hub, the worse the food is. I want to ask sometimes, "would it have cost you any more money to serve me a pizza which didn't taste like poop?" I just don't get it...
================= I avoided large cities if possible. The Army bases I visited to work on comm gear were either on the edge of town or in remote areas like Vilseck. Generally I could find a good meal in a small to medium town's Gasthaus, or a restored castle's restaurant. I stumbled onto an excellent pig roast in the banquet hall of a castle far off the tourist track where an American GI like me was still a curiosity.
I had a set of the Shell road maps that showed contour lines, buildings, ruins etc in enough detail to plot artillery fire. I bet the Russians had them too.
The exception was when my parents came over to visit. As neither knew German I took them to downtown places more likely to speak English. The Chinese restaurant near the Dom in Koeln wasn't bad. I don't think they really appreciated JaegerSchnitzel or Spaetzle as much as I did.
jsw
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    Hmm ... can you handle a short workpiece at a greater diameter? Is the 14.5 cm radius based on clearing the carriage, or on just barely clearing the ways?
    It doesn't look to be a gap-bed lathe, so that is not an option to get a bit larger diameter workpiece in there.

    Sanding dust goes *everywhere*. If you are going to be sanding, cover the ways, carriage and tailstock with newspaper wet in oil to trap the dust -- and do as much as you can to keep the dust from getting inside the headstock covers, as you will abrade the threading gears as well.

    Turn back a bit behind the square end to be a press fit for a compression spring -- two diameters -- one to allow the spring to move a bit, and one closer to the T-handle to trap the spring. Push on a spring which is long enough to push the key out of the socket whenever your hand is not on it -- and make a tube to hold it the rest of the time -- someplace easy to reach, like the front edge of the table it is mounted on. Easy enough to bolt something onto the perforated angle iron which is supporting the table top. Or ever thread some coat-hanger wire through two holes to make a complete loop plus a bit before turning into the holes.
    Some chuck keys (such as my Bison 6-1/4 inch one) come with such a spring. I've left mine in place, though some pull them off.
    [ ... ]

    [ ... ]

    [ ... ]

    I've got a three-wheel benchtop bandsaw which includes a mounting for a disc on the fastest running hub -- and that might work well, as there is not as much precision machinery in the bandsaw. :-)
    A pity that you can't find Harbor Freight there. Yes, they have really poor quality -- but also very inexpensive. I got a little disc/belt sander from them about a month ago. I had to pull it apart and properly re-align it so the disc plate did not bind on the guard. And do a little work to minimize the wobble of the disc plate. But for less than $30.00, it was worth it.
    And in their monthly flyer, they've got a 6" disc, 4" belt for $59.99 (regular price $99.99, but I don't think *anyone* pays regular price. :-)
    Is there some importer there like Harbor Freight?

    I recognize that name. Welcome back!

    Nope. Only those who are willing to keep a really active killfile. The political junk from trolls has been chasing off most of the better regulars.

    I'm sort of putting my shop back together after a fire badly smoked it and rusted a lot of things. Since the shop has been cleaned out and re-drywalled it I've been setting things back up and using something called Evapo-Rust (which is actually carried by Harbor Freight, and does the job without containing hazardous chemicals. I've been de-rusting BXA sized toolpost tool holders, and smaller ones for the little Emco Compact-5/CNC lathe (Dickson style), as well as various other small tools.
    Good Luck with re-building your shop,         DoN.
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I hung one of these on the wall behind the lathe: http://www.organizeit.com/wall-mount-tool-rack.asp?cmpid=gpa&gclid=CPOay7ipmbwCFU_NOgodGlsA7w It holds screwdrivers, wrenches, files etc in the front, serving as a guard rail, and toolholders on the rear step. The center of the front row is left open for the chuck key. Below it in the mounting plank a row of L hooks holds inside and outside calipers and old-style square box wrenches. jsw
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That's the ways. Only 8cm over the carriage. Like I said though, there is a small shop nearby which would do this for me for a reasonable price.
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Don, Yeah, it's too bad what has happened to this forum. I started reading it in the late '90's when I had just started up a commercial art shop and knew v ery little about machinery (not that I'm an expert now!). RCM was incredibl y valuable to me then. It was almost like having a team of veteran machinis ts dropping by for an hour every evening, looking over my operation, and of fering tips and criticism. Now you have to really scroll to find anything r emotely on topic. All good things... It's encouraging at least that this th read turned out to have been worth something. Now that I'm back in the game I'll start checking in here again.
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    The more valid metalworking threads the better. Right now the total volume seems to be falling (in the past few weeks), and the percentage of metalworking increasing a bit, so there may be hope.
    Of course, I do still run an active killfile. But I've seen it leave only about 10-15% and today it was closer to 50% I think. (Unless it is an artifact of news propagation and things are worse elsewhere.
    Some have gone off to web based fora -- but I just can't be comfortable using a web browser to type in articles. :-)
    A couple of metalworking-related mailing lists still going. One for the local metalworking club (Washington DC vicinity), and the other more international, and focused on model building, with metalworking one of the necessary parts of that.
    Enjoy,         DoN.
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On Thursday, January 23, 2014 2:51:23 AM UTC-8, snipped-for-privacy@yahoo.com wrote:

a 12" disc sander in my shop, but in my country (Germany) they are quite ex pensive, even used. I'm thinking of trying to kludge one on to back of the lathe, and mount a tilting table to the back cover (see link 2). This would save space, and I'm not that busy at the moment.

here's not much to attach to back there. My idea is to mount the disc plate to a long rod which goes all the way through the spindle bore and is then held by the chuck. Since the spindle bore is only 26mm, I'd need to make so me sort of adapter ring to make everything stable (See drawing - link 3). I feel like this should work, if a bit quixotic. Any ideas on whether or no t I'm on the right track, or if there would be another way to attach the di sc to the spindle? Ideas on the tilting table? I'm planning on doing everyt hing with aluminum, since I don't have a milling machine.

whole business must be easy to remove. The cover is fairly beefy, so I thin k with some reinforcement bars I can mount a table which would work well en ough.

I don't have to worry about voiding my warranty. The machine is twenty yea rs old!

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Just a few more things.
I'm pretty good at managing dust: http://i389.photobucket.com/albums/oo340/robobass/Werkstatt/100_0867_zps687 70c49.jpg I do quite a bit of polishing work, so it's a priority.
There's no HF or McMaster here. You can however find an amazing amount of s tuff on Ebay if you're willing to search hard enough. The three machines yo u see in the photo were quite inexpensive and have lasted ten years so far. Once you go from a little belt sander to a 12in disc sander, the options f rom the lower end quickly disappear, and used machinery in general is more expensive and less available than in the States. I paid almost 1600 USD for that lathe. I bet it would fetch a third of that in US.
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On Sat, 25 Jan 2014 06:57:13 -0800 (PST), snipped-for-privacy@yahoo.com wrote:

I like your triple French door. Looks handy for machinery moving.
I dunno about putting the dust exhaust 6" away from the unprotected intake vent, though.
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Wasn't much choice. I just don't run them both at the same time. There is a filter in there, of course.
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On Sun, 26 Jan 2014 01:13:17 -0800 (PST), snipped-for-privacy@yahoo.com wrote:

Oh! I didn't think the intake was powered. It looked like a plain air exchange tube and I couldn' see a filter element in there.
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Yeah. There's a fan on the door at the end of each tube. The top one blows out (filter in the box) and the bottom one blows in. I stop the bottom tube at the other end with a bucket. I suppose some dust will accumulate in the bottom tube, but so far the blades on both fans are totally clean, so my f ilter seems to be effective.
As to dust on the ways, I'm with PCS. I've always done a lot of sanding and shaping with a scraper over the ways, and never seen any consequence. Just clean up after yourself, and not only the ways, but the lead screw too. Th at thing really likes to crud up when dust is around!
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