Posted: 1/20/2009 6:03:56 PM EDT
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It doesn't look like we have a machining forum (DIY Forum maybe?), so I had some questions I thought i'd bring up for all of the machinists we have here on Arfcom.
My Dad was a machinist in his younger days working for North American and working on government contracts including the Apollo missions ("here, this is a blue print, build it, no, we won't tell you what it is or what it does"). I would like to learn some of what he knew, but don't have any equipment. I'm not interested in super expensive, nor am I interested in high tech. I've looked around a little and found www.mini-lathe.com and www.mini-mill.com. He still has some of his mics and depth gauges, so that expensive part of the hobby is covered, but I was wondering on input on good equipment and sources to buy that equipment to use on a garage work bench. Also, what are the limitations of these smaller units? Is it an issue only of size of the material being machined, or are there issues with the quality of the machining? Do these machines do things like inside and outside threads? Lastly, what kind of budget should the beginning hobbyist be expecting? 
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Here is are some cool links its a how to build a 10 machines in one
multi machine http://opensourcemachine.org/the-multimachine pdf file on how to build it 
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I have this one, LINK
It pretty much does everything I want to do at this point in time. Uses a standard R8 collet, and is accurate enough for hobbie work including making gun parts. As far as the lathe, I am holding out for something with at least a 1-3/8 spindle bore, most of the barrels I would work on are 42" long. I am probably going to find a used great bend or something, but I have to pour a new floor in my shop before I would put that much weight in there. What do you have now, perhaps we can give you advice on what else you need? Here is mine, cutting dovetails for barrel lugs. 
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I have this one, LINK It pretty much does everything I want to do at this point in time. Uses a standard R8 collet, and is accurate enough for hobbie work including making gun parts. As far as the lathe, I am holding out for something with at least a 1-3/8 spindle bore, most of the barrels I would work on are 42" long. I am probably going to find a used great bend or something, but I have to pour a new floor in my shop before I would put that much weight in there. What do you have now, perhaps we can give you advice on what else you need? Here is mine, cutting dovetails for barrel lugs. http://i392.photobucket.com/albums/pp2/angrytek/100_1579.jpg Currently I have nothing, other than some mics, dial indicators, dial test indicators, depth gauges, and feeler gauges. |
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I have this one, LINK It pretty much does everything I want to do at this point in time. Uses a standard R8 collet, and is accurate enough for hobbie work including making gun parts. As far as the lathe, I am holding out for something with at least a 1-3/8 spindle bore, most of the barrels I would work on are 42" long. I am probably going to find a used great bend or something, but I have to pour a new floor in my shop before I would put that much weight in there. What do you have now, perhaps we can give you advice on what else you need? Here is mine, cutting dovetails for barrel lugs. http://i392.photobucket.com/albums/pp2/angrytek/100_1579.jpg Currently I have nothing, other than some mics, dial indicators, dial test indicators, depth gauges, and feeler gauges. Once you decide on your machine, this will pretty much dictate which collets you would need to hold you endmills. You'll need a few T-Nuts for your table. Your machine will also dictate which size slot you need them for. This is one of the things I wouldnt cheap out on, I use Gibraltar. You can also save some money by getting cap screws from a nut and bolt supplier (not home depot junk) Most of these are a grade 8 or better and ALOT cheaper than buying a set of studs. A table vice, the one I have in the picture I found used from a guy that deals with used machines, it works alot better than the Grizzley one I got first and cost me next to nothing. at least 1 better to have 2 sets of 123 blocks. the imports are plenty good enough for this, MSC runs them on sale pretty often. A set of parrallels is something that is also pretty necessary, I use mine alot. Imports are fine for this too. Angle blocks are pretty handy as well. Endmills Your fine to start our with a few import carbide 1/4" and 3/8" endmills to get some practice playing with the machine. When you figure out which ones you used the most, then upgrade those to something more premium. (OSG, Atrax, Accupro, Hertel are all very nice tools) This is the same with your drill bits and taps. Cutting oil. There is a ton of stuff out there, most of which neither one of use will use a machine that would actually reap the benefits of it. For cheap I use Rigid dark cutting/tapping oil. I am still on my first gallon from 2 years ago. The best way I found to collect tools is watch the sale flyer. These guys have pretty much everything you will ever need and then some. MSC (they usually do maint on their site every night, so look at it in the afternoon or evening |
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I buy my tooling here:
Shars Also check out: Little machine shop |
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I have both the mini-mill and mini-lathe. My thoughts on them and setting up a home shop are here:
http://www.geocities.com/kemays Limitations? I wouldn't want to work on anything larger than a handgun on the mini-mill, and sometimes it can be tough to do something even that big. For things like cutting sight dovetails and making simple, small parts, it works fine. Table and quill travel will be your biggest limitations, and you will notice it more when you have multiple operations to do, or machining over a large area. Ideally you want to be able to do minimal setups on the table without having to move your part around to reach other areas on the workpiece. You'll also be limited by the size of a mill vise that you can install on the table. Example: my vises aren't quite big enough to get as solid a hold as I'd like on an AR-15 lower. The quality of the machining itself is adequate for most home hobbyists. Initial setup of the machine will be critical. They come out of the box loose and crooked. Quality endmills and solid, square workpiece setup will help a lot, as well as proper measurement. I found out pretty quickly that it was frustrating to have to use the dials to count my distances, so I installed a set of digital readouts that I refuse to do without now. The mini-lathe has surprising features for what it is. I've cut threads on mine, but that's kind of a pain in the ass. It can be done if you have enough patience. Like the mini-mill it comes out of the box loose and crooked. The headstock spindle is frustratingly small. I would give a lot to have a full 1" spindle bore on this damn thing. The bed travel is usually not a problem for what I work on, but it does mean things can get awfully tight, between your tailstock and toolpost and whatnot. Cutting tools are a weird size, I think 5/16" is about what you want. You will be grinding your own out of blanks for best results. Things like knurling tools, cutoff tools, etc. will be hard to find for a lathe this small, so you will have to buy the smallest ones you can get and cut 'em down. Honestly I use the lathe a lot more than the mill. I'm always using it to make pins, tools, and to chuck up parts that I want to modify or polish. I'd love a larger lathe, maybe the Grizzly 9x20, but the mini-lathe is so handy I think I'll always have it on hand. |
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First of several bumps, I know there are some heavy hitter machinists in here.
Thanks for the input so far, please keep in mind that this thread is for dummies, so some of the technical terms you are using aren't registering unless I google half of the terms in your post. 
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First of several bumps, I know there are some heavy hitter machinists in here. Thanks for the input so far, please keep in mind that this thread is for dummies, so some of the technical terms you are using aren't registering unless I google half of the terms in your post. Yes there are, I am sure they will contribute. 
I was kindof in a similar situation as yourself. Dad is a tool/die maker now working on CNC. He pretty much started out doing motor armatures back when I was a few years old, and did manual machining up until the last 5 years or so when he got into CNC. He has send me quite a few different tools, and we've spend hours on the phone going over different ways to do things, tools to get, tools that are nice to have, and tools that i probably will never need. Also about 15 years ago when he was still living in this area, I would stop down where he worked on days I didnt have school and would get some time to use the machines a bit. (this was pre-lawsuit / liability crap) I was doing some of my school shop projects because the machines at school were beat up pretty bad. I was interested in doing this for a while, but could never find a way in. |
You guys do it the hard way
M60, EOB ,Incert, Cycle Start.......Select pallet, highlight program numbert, incert, then cycle start....time for a break "where is the coffe and donuts" now if I can just get someone to load my pallet and change tools for me 
Man I miss the old CNC lathe and mill jobs 
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| Would a mill and lathe like this allow you to make things like free float tubes, rails, and the like? I know i wouldn't get something like this and start whipping out works of art, but I want to know what the capabilities are given some experience or if you would need a lot more expensive equipment to do things like that. |
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Buy a decent lathe and retrofit it with CNC motors.
I know where you can get some decent 425oz/in bipolar motors for $79/each. Drivers for about $40/each. Breakout board for $10-$15 unless you want to get one with about a million different pins for dedicated limit switch and home switch inputs. Then use EMC2 (free linux program) on a PC for your controller. Advantage of starting with a lathe, I think, is that you can build any custom parts you need to mount all your cnc electronics, yourself. Once you've got that, you could build your own dedicated mill, no problem. I'm kind of going about it backwards and in a more caveman way. I started by building a CNC router. And not a very good one. I then used that one to cut out another, more accurate and capable one. Once I finish building that one, at some point I'm going to use it to cut out foam cores for casting my own metal lathe parts. I'm going to try the dave gingery method of machine shop construction, only instead of cope/drag casting, I'm going to try investment casting. |
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As a machine shop owner, I can tell you there are great deals now at auctions. If you can spare the time to go to them, it's worth it. There are a lot of shops closing. Even Ebay has had some great deals. You can pick up a mill and lathe that were meant to be used, and used hard, for little money.
I'd take a twenty year old Bridgeport mill in good shape, over a new table top mill any day of the week. The new, cheap machinery just can't compare. If you could try one out, then try out an actual industrial machine, there would be no question. ETA: If you were closer, I'd tell you to stop by and try one out. |
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As a machine shop owner, I can tell you there are great deals now at auctions. If you can spare the time to go to them, it's worth it. There are a lot of shops closing. Even Ebay has had some great deals. You can pick up a mill and lathe that were meant to be used, and used hard, for little money. I'd take a twenty year old Bridgeport mill in good shape, over a new table top mill any day of the week. The new, cheap machinery just can't compare. If you could try one out, then try out an actual industrial machine, there would be no question. ETA: If you were closer, I'd tell you to stop by and try one out. +1. eBay has some older Bridgeports, say a 9x32 Model 2 for $1200, plus freight. $400 in tooling can take you far. MSC and Enco are your friends. Auctions are great to. My company just bought a complete shop that was closing for $8K, Mig, Tig, Mill, Lathe, bandsaw, 2 brakes, tables, tool boxes full of tooling, carts, even lights. |
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As a machine shop owner, I can tell you there are great deals now at auctions. If you can spare the time to go to them, it's worth it. There are a lot of shops closing. Even Ebay has had some great deals. You can pick up a mill and lathe that were meant to be used, and used hard, for little money. I'd take a twenty year old Bridgeport mill in good shape, over a new table top mill any day of the week. The new, cheap machinery just can't compare. If you could try one out, then try out an actual industrial machine, there would be no question. ETA: If you were closer, I'd tell you to stop by and try one out. How difficult would it be to buy a "junk" bridgeport that's got worn out leadscrews and/or worn out transmission nut and just replace them? Could you get a good deal that way? eta: Which part usually wears out first? The nut or the leadscrew? For that matter, what sort of transmission do bridgeports normally have? Regular acme screw and some sort of dual nut for AB or ballscrews/nuts? |
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First and foremost- Don't go for the lathe/mill combos. They tend to neither job very well and are frequently poorly made. It seems like a good idea on paper, but it just doesn't work.
You will probably find a small mill to be the most educational and immediatly useful. In the long run you'll find a lathe to be far more powerful, although the skills and tooling are harder/more expensive to come by. There is always a debate as to which machine a new machinest should learn to use 'first'. I found the mill the most interesting and easiest to understand, so thats what I suggest. I strongly recommend theRong Fu 45. I've worked on several and I've been impressed. They are solid, well designed and made machines. There are a lot of Chinese knockoffs of this design, so be careful you get the real Taiwanese stuff. Most important is that they have a square column. Cheaper machines have a round column which results in a great deal more work for you every time you need to move the head. And, once you've mastered 'manual' milling, there are a bevy of CNC upgrade kits avalible for this mill. But. Before you go spluge on a mill, you should have a well rounded set of hand tools, bench grinder, belt/disk sander, table vice etc. I would also recommend that you have at least a small wood cutting band saw and a small drill press. You should also have a fair idea of how to use all that stuff, how to lay out features on metal and all the classic safety stuff. And, when you do finally get the mill, expect to spend at least half of it's price on tooling before you approach its capabilities. Like firearm optics, your tooling can easily exceed the cost of the original machine. This is an expensive hobby which is why most people do it as a living instead. While it is fun, you are going to break expensive tools, ruin material, cut your hand, bruise your head and probably piss off your wife. Have fun! |
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As a machine shop owner, I can tell you there are great deals now at auctions. If you can spare the time to go to them, it's worth it. There are a lot of shops closing. Even Ebay has had some great deals. You can pick up a mill and lathe that were meant to be used, and used hard, for little money. I'd take a twenty year old Bridgeport mill in good shape, over a new table top mill any day of the week. The new, cheap machinery just can't compare. If you could try one out, then try out an actual industrial machine, there would be no question. ETA: If you were closer, I'd tell you to stop by and try one out. How difficult would it be to buy a "junk" bridgeport that's got worn out leadscrews and/or worn out transmission nut and just replace them? Could you get a good deal that way? eta: Which part usually wears out first? The nut or the leadscrew? For that matter, what sort of transmission do bridgeports normally have? Regular acme screw and some sort of dual nut for AB or ballscrews/nuts? I would not buy a "junk" one. There are too many good deals on good ones. I bought one with ball screws for $700 last spring, I ended up selling to a friend for what I paid. Kinda wish I kept it, you can't have too many. If you are going to CNC retrofit one, go with ball screws. They do have a different feel for manual machining. Some guys like them better for manual, some don't. Ballscrews require less driving torque than a leadscrew, but they have their drawbacks too. You can usually adjust the nut a few times before you need to think about your leadscrew. You'll find more lead screw manual mills than ball screw. |
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As a machine shop owner, I can tell you there are great deals now at auctions. If you can spare the time to go to them, it's worth it. There are a lot of shops closing. Even Ebay has had some great deals. You can pick up a mill and lathe that were meant to be used, and used hard, for little money. I'd take a twenty year old Bridgeport mill in good shape, over a new table top mill any day of the week. The new, cheap machinery just can't compare. If you could try one out, then try out an actual industrial machine, there would be no question. ETA: If you were closer, I'd tell you to stop by and try one out. How difficult would it be to buy a "junk" bridgeport that's got worn out leadscrews and/or worn out transmission nut and just replace them? Could you get a good deal that way? eta: Which part usually wears out first? The nut or the leadscrew? For that matter, what sort of transmission do bridgeports normally have? Regular acme screw and some sort of dual nut for AB or ballscrews/nuts? Replacing lead screws and nuts is a messy, but not terribly difficult, job. Idealy the screws and nut wear in such a way that it's never really an issue. Thats rarely the case however. Typically the nut wears and needs to be replaced whenever you get sick of dealing with the whatever amount of backlash is present. I would replace after 5 thousands of backlash if using dials, and a great deal more if using a DRO. Manual mills almost always have traditional ACME lead screw and nut profiles. Ball screws don't have backlash but offer very little resistance and would be horrible to use in a manual mill. It works great in CNC machines because they will hold the table in position against cutting forces. You're hand isn't that good and inevitably the table will take off on you. |
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...Some guys like them better for manual, some don't. ... Yeach. That just sounds like a recipe for a trashed part. At some point you'll forget to set the brake on an axis, start a cut and watch that bit just take off into the material. To each his own, I guess. After all, the only thing two machinists will agree on is what the third is doing wrong. |
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...Some guys like them better for manual, some don't. ... Yeach. That just sounds like a recipe for a trashed part. At some point you'll forget to set the brake on an axis, start a cut and watch that bit just take off into the material. To each his own, I guess. After all, the only thing two machinists will agree on is what the third is doing wrong. You and I are on the same page on that. There will always be some guys out there with the wrong opinion, though.
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As a machine shop owner, I can tell you there are great deals now at auctions. If you can spare the time to go to them, it's worth it. There are a lot of shops closing. Even Ebay has had some great deals. You can pick up a mill and lathe that were meant to be used, and used hard, for little money. I'd take a twenty year old Bridgeport mill in good shape, over a new table top mill any day of the week. The new, cheap machinery just can't compare. If you could try one out, then try out an actual industrial machine, there would be no question. ETA: If you were closer, I'd tell you to stop by and try one out. How difficult would it be to buy a "junk" bridgeport that's got worn out leadscrews and/or worn out transmission nut and just replace them? Could you get a good deal that way? eta: Which part usually wears out first? The nut or the leadscrew? For that matter, what sort of transmission do bridgeports normally have? Regular acme screw and some sort of dual nut for AB or ballscrews/nuts? Replacing lead screws and nuts is a messy, but not terribly difficult, job. Idealy the screws and nut wear in such a way that it's never really an issue. Thats rarely the case however. Typically the nut wears and needs to be replaced whenever you get sick of dealing with the whatever amount of backlash is present. I would replace after 5 thousands of backlash if using dials, and a great deal more if using a DRO. Manual mills almost always have traditional ACME lead screw and nut profiles. Ball screws don't have backlash but offer very little resistance and would be horrible to use in a manual mill. It works great in CNC machines because they will hold the table in position against cutting forces. You're hand isn't that good and inevitably the table will take off on you. Actually, I do believe ballscrews can have backlash. If the balls are not absolutely perfect or the screw itself isn't absolutely perfect, there will be backlash. However, for practical purposes, the ballscrew nuts that I've seen seemed to be a dual nut working against eachother for pre-load to take up any backlash present. Of course, I have never worked with ballscrews, so I could very well be talking out my ass. I do know that they're great for CNC purposes due to their high efficiency in energy transmission. Rolling > sliding. |