Date
1 - 9 of 9
Milling Machines
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Bill Welch
Gentleman
I have been spending time online looking at small milling machines as I anticipate some model making/building challenges. For example one project could involve cutting apart several SFRD 50-ft reefer roofs and reassembling into something very different. This is something requiring more precision I believe than a razor saw and NWSL True Sander can accomplish. Another task will be to remove unwanted material from the surface of something very cleanly. In addition to styrene, I imagine work with resin and brass. So far I have identified three systems: Sherline--which is the smallest machine at 20.75 inches high, 33 lbs and "electronically" controlled motor speed with an incredible website with great information that helped me understand what I will probably want in terms of a cutting or milling device. Did not see HP of the motor stated Taig is 21 3/8 inches tall and weights 65 lbs and 1/5th HP motor if I read and understood it correctly. One dealer has a website that looks exhaustive and probably more serious than my needs. More of a dedicated machinist resource Micromark/Harbor Freight which from what I can tell are the same machine appearing under other labels as well. (There is a Harbor Freight very near me and I went over to see if the had one on the floor but they did not. They did have the equivalent lathe from the same manufacturer and it is a serious tool.) It mill has two variable speed ranges with a .47 HP motor, is 110 lbs. and 33 3/4 inches high. The Micro Mark/Harbor Freight examples are bigger than I need I think. Initially I believe most of my work will be with 3/8 inch shank "End Mills" to do the cutting. These cut on the end and the side. Pricing on all is fairly close IMO. I am wondering if anyone on this list has experience with any of these systems and can comment on them? Bill Welch
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steve_wintner
bill, I own a proxxon mf70 (check model expo) and have used a sherline.
I have heard that the harbor freight machines are sturdy but not so accurate. hearsay only. heard of taig but cannot recall anything that stood out. from experience I think a sherline is ok but requires some careful use and setup. the proxxon is very small (they do offer some larger models) but I have been pleased with the accuracy out of the box and also the ease of adjustment. bang for the Buck Has been quite good. one concern is that to use very small mills you need a very high rpm, which most mills cannot do. the proxxon does. and for the tasks you describe a 3/8 that bit will work, sure, but is overkill. think of milling off molded on grabs... so my 0.02 is to take a look at the proxxon, but the sherline should serve. have fun steve Wintner
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Jack Burgess <jack@...>
I have both the Sherline milling machine and a Sherline lathe. I haven't
used them that much but they have done a very good job on each project that I did use them on. Tolerances are tight, specs are very good, and I like the fact that the machines and accessories are all made here in the US. I also like the fact that Sherline has a lot of accessories for their machines as more complex projects come up. I have never taken any machining classes so owner Joe Martin's Tabletop Machining book has a lot of good information for newbies like myself... Jack Burgess www.yosemitevalleyrr.com
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Trackman <jfpautz@...>
--- In STMFC@..., Bill Welch <fgexbill@...> wrote:
Sherline--which is the smallest machine at 20.75 inches high, 33 lbsBill, I have three Sherline mills and use them constantly, have not had any problems with them. Also, Sherline has the best selection of accessories of any that you listed. I have probably more invested in "tooling and accessories" than the mills originally cost. John F. Pautz American Switch & Signal P:48 track components
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Bill Welch
Thank you Jack & Steve:
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I did look at the Proxxon Machine and it looks like another good candidate. One thing did concern and that is its speed (5000 rpm the slowest) when using it with styrene. I am worried it will melt the styrene. Bill Welch
--- In STMFC@..., "steve_wintner" <steve_wintner@...> wrote:
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I have had a Sherline for years and I like it. Mine is totally manual...
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Prototype N Scale Models (TM) by George Hollwedel PO Box 143566 Austin, TX 78714-3566 512-579-0539 512-796-6883 cell http://www.micro-trains.com/sr-1008-hollwedel.php http://www.micro-trains.com/hollwedel.php http://www.atlasrr.com/special.htm http://www.imrcmodels.com/n/sr/nsr.htm
--- On Mon, 8/16/10, Bill Welch <fgexbill@...> wrote:
From: Bill Welch <fgexbill@...>
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Dennis Storzek
--- In STMFC@..., "steve_wintner" <steve_wintner@> wrote:
Steve, I suspect that Bill is thinking of smaller HSS (High Speed Steel) milling cutters with 3/8 shanks, and of course, the speed of the tool is calculated on the actual cutting diameter, not the shank size. When Bill gets into this further, he will find that there are all sorts of "miniature" end mills available with 3/16" shanks, and even smaller carbide end mills with 1/8" shanks. To view a selection, go to http://www.mcmaster.com/ and search on page 2478 for the HSS, 2485 for carbide. --- In STMFC@..., "lnbill" <fgexbill@...> wrote:
Bill, Melting the plastic is not an issue when milling. Melting is cause by the friction of a tool rubbing against the work. Since a milling machine keeps the tool properly oriented, it cuts rather than rubs, so the chips come off as fine shavings. I typically do CNC work on plastic, mostly ABS, which cuts similar to styrene, with the spindle running balls-to-the-wall at 5000 RPM, and wish I had more speed. So long as the chips don't wrap around the tool and rub the work, they don't melt. Having a source of compressed air to continually blow the chips away is helpful, but messy. Rigging a shop-vac to blow the chips into might work. The down side of running too slow a spindle speed is you can't feed at a decent rate, and will break cutters because you get bored by the need for sloooow feeds. Not a problem with CNC work :-) I'm going to suggest a couple things others haven't touched on yet: Make sure if you buy a metric machine that it comes with collets in at least 1/8" and 3/16" imperial sizes, or you will be severely limited in the selection of end mills you can find with metric shanks. They certainly exist, in Europe, but not here. Yes, you can grip any size shank in a drill chuck, but it isn't good practice. First off, drill chucks aren't designed to withstand side loads, so you may knock it off its tapered mandrel when milling. Secondly, inexpensive hobby grade chucks have a lot of "runout": lack of concentrically. This not only affects the surface finish of the cut, but tends to break little drills and cutters. Collets are better for precision work. Also, I wouldn't buy a machine with metric lead screws, as you will forevermore have to convert all your dimensions to mm. Not a problem if the machine has a digital readout, but I'm not aware of any of the little machines so equipped. Even a cheap two axis DRO is worth about $1200, if it would even fit these small mills. Also, get a machine with the biggest table you can. Our models tend to be made from relatively soft materials, and it often takes some creative fixturing to hold it to work on it. Very few things can just be held in a vise. Many years ago I had one of the original Edstal Unimats, the little 3" x 4" milling table was just about worthless for everything. Dennis
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Frederick Freitas <prrinvt@...>
GUYZ,
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Would the Unimat model builders unit work for this application? Fred Freitas
--- On Mon, 8/16/10, lnbill <fgexbill@...> wrote:
From: lnbill <fgexbill@...> Subject: [STMFC] Re: Milling Machines To: STMFC@... Date: Monday, August 16, 2010, 5:49 PM Thank you Jack & Steve: I did look at the Proxxon Machine and it looks like another good candidate. One thing did concern and that is its speed (5000 rpm the slowest) when using it with styrene. I am worried it will melt the styrene. Bill Welch --- In STMFC@..., "steve_wintner" <steve_wintner@...> wrote:
[Non-text portions of this message have been removed]
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Kurt Laughlin <fleeta@...>
I have a mill-drill, which may be a bit bigger than you are considering, but I often work with metal so I wouldn't wan't anything smaller.
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For the machines you are considering, I recommend these sites: http://www.mini-lathe.com/Mini_mill/Main/mini-mill.htm http://www.arceurotrade.co.uk/projects/prepguides/X3%20Mill%20Preparation%20Guide.pdf http://www.littlemachineshop.com/Info/MiniMillUsersGuide.pdf http://www.littlemachineshop.com/Info/minimill_compare.php http://plsntcov.8m.com/grizzley.html http://www.davehylands.com/Machinist/index.html Some show modifications or other brands, but you can see other's opinions on the machines, and learn of the many vendors out there. KL
----- Original Message -----
From: Bill Welch I have been spending time online looking at small milling machines as I anticipate some model making/building challenges. For example one project could involve cutting apart several SFRD 50-ft reefer roofs and reassembling into something very different. This is something requiring more precision I believe than a razor saw and NWSL True Sander can accomplish. Another task will be to remove unwanted material from the surface of something very cleanly. In addition to styrene, I imagine work with resin and brass.
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