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Re: end mill holder
开云体育I’m a certified beginner. ?This was one of the first successful things I made.Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod. On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
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Re: end mill holder
Can you get away with using a drill chuck to hold an end mill? Probably. Maybe. Sometimes. :) On a Unimat the forces are likely to be lower than on larger machines. BUT! The end mills you're using on a Unimat are likely to be small & fragile, so more likely to be damaged. Pull-out is probably the most likely problem. The forces applied pull the cutter into the material being cut, which can overload the cutter, pull the material out of the clamps, and shatter the end mill.? Drill chucks make lousy end mill holders. They aren't really even all that good at holding drill bits. They grip along a narrow band in 3 locations 120 degrees apart with a curved surface that is very likely to slip. How many times have you seen a drill bit that has spun in the chuck? The shank gets torn up and can no longer get anything like concentricity.? The fingers used in drill chucks to grip the drill bit shank are hardened, and frequently slip on a drill bit with a relatively short shank. They're used because they easily adjust to any size shank within their range, not because they grip reliably. Can you imagine buying a set of collets made to hold drill bits in .001" increments? Or less? Yikes! You'd need a set of nearly 1000 collets...? End mills have hardened shanks and a drill chuck cannot reliably grip them. Weldon shank end mills were invented because straight shank end mills can still slip even in? properly sized end mill holders? or collets due to the forces involved. And even Weldon shank end mills in proper holders can be broken.? There are tables that show the appropriate sizes for Weldon shank end mills & end mill holders, and they're not all that difficult to make. End mills come with a limited number of standardized shanks, so you only need a few end mill holders. Weldon shanks aren't perfect. They pushed the cutter off-center, and off balance. And there are probably dozens of other systems for holding end mills, but not all of them scale well for a Unimat.? I have personally pulled a Weldon shank 1/2" end mill out of the holder and destroyed it and my part, on a Bridgeport-class milling machine. Was not quite spectacular, but was startling! :) Unimats aren't nearly as powerful, and you're unlikely to be using a half-inch end mill on one, but an eighth-inch end mill isn't nearly as strong and the parts you're making are probably much easier to destroy.? And making tooling like end mill holders is good practice for more complex projects. OK. Off my soap box now! ;) Bill in OKC? William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 06:43:06 AM CDT, Peter Brooks <peter@...> wrote:
Or of course a drill chuck. Depends what you are trying to do and how accurate you need to be. Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier Unimats) are probably easier to find than collet chucks with those threadings. |
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Re: end mill holder
开云体育Hi
Gang: It is easy to drill and tap a drill chuck to fit Unimats, I've done it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck converted in 1973. While you can hold a milling cutter in a drill chuck, you will not come close to cutting capacity of the cutter. Most likely the cutter will move or even be ejected by cutting forces. Much better is to make solid cutter holders from 3/4" bar stock. Drill and tap to match the spindle then bore for your cutter and add a set screw to clamp the cutter. I have 3/8" and 1/2" holders that work fine. Carl. On 9/5/2023 7:43 AM, Peter Brooks
wrote:
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Re: Feed Transmission For Mini Lathe ?
开云体育Hi Gang: I built a power feed for my Unimat with the motor from my Erector set. I arranged the gears to have two speeds forward and back. To connect it I used a 10mm hex socket to connect to the handknob nut with the Erector set flex shaft. Worked great, but more nuance to me than just turning the cranks. If I
did it again I would use an Arduino with a stepping motor to
get full speed control. I think you could build one for less
than $50. Carl. On 9/4/2023 9:58 AM, Keith S. Angus
wrote:
The alternative approach is to drive the lead screw with something like an electric screwdriver. No rubber bands or gears needed, and I reckon most people have one or two of them sitting about doing nothing most of the time. I binned a few last time I has a clear up in the garage. |
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Re: end mill holder
Hello Bud!
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You could easily make your own and probably machine one up on your own U3. Not difficult to do. Dick On Monday, September 4, 2023, 12:48 PM, zinneckerbud@... wrote:
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http://www.homemadetools.net/ ?SMALL TURRET TOOL POST PLANS? ?LARGE TURRET TOOL POST PLANS ?MINI- ?SMALL QC TOOL POST PLANS? ?QUICK CHANGE LATHE TURRET ?MINI LATHE COMPOUND PIVOT MODIFICATION |
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Re: How many Unimats is too many?
I have five lathes, only two are Unimats. Also four milling machine. Though two of those are Unimats. And three of my machines can be a lathe, mill, or drill press, though only two of them are Unimats. Had 6 drill presses, until yesterday. Gave the 8" Central Machinery to my neighbor. And again, only two are Unimats. :) Versatile machines!? :) Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Monday, September 4, 2023 at 03:15:32 AM CDT, Unimat Matt <matthewtay2020@...> wrote:
I currently have 9 lathes. Though not all Unimats. ??
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Re: Feed Transmission For Mini Lathe ?
Hi Clankennedy,
I did it a different way I did not want to get into belts, pulley's, gears I used two double ended stepper motors so direct fixing and found two single action controllers, and it works very well on long work takes all of the hand winding away. I replaced the way bars with longer to fit the motors to. I fitted thrust washers to the leads screws to help reduce any drag, and you can set up repetitive cuts just great. I also made two knobs to fit on motor shaft so with power off I can use the lathe by hand for small close work And I made up the box with its own 24v dc power supply and wires for the controllers, just need to plug it into the mains and switch on. I have also picked up a spare cast bed and fitted longer way bars to use just for turning wood or plastic.?? I retained all the original parts and could go back to a normal lathe again. |
Bill in OKC too
Carl
OldToolmaker
Unimat Matt