Suppose we had $5000 to spend on machining equipment (just suppose). How far could it get us. Let’s explore some different options: Combo Machine, Mill and Lathe, Small CNC, CNC retrofit, Etc.
If you had no machining equipment, but you had $5000 to purchase some, what (specifically) would you buy and why? Say you already had some access to any type of machine, but not at any time you wanted. Say you want machines to have at your normal work place that you will be able to access any time.
I’ve been looking at the Grizzly G3102 milling machine. Is it any good? What other machines are out there.
We get by without a mill, but a lathe would be helpful sometimes. Maybe if we had access to a mill, I’d change my mind. But we don’t, and we DO have access to the 12 X 7 Grizzy lathe if we really need it. (It’s in my house, about 30 minutes from our build area.)
Remember, you have $2500 to spend on machine tools, because the other $2500 goes to tooling for the machine. (I’ve spent more on tooling for my Grizzly 12X7 lathe than I did for the lathe.)
I thought this question sounded familiar. See this post. Rick asked the exact same question but the amount was only $2500. My response is still valid. Mill first then Lathe. You need something to cut up long stock with as well.
I would still look at the Rong-Fu mill/drills. (See Option 2 in the linked post).
I actually hear decent things about this bandsaw for cutting long stock in the sizes the a FIRST team would probably use.
I have been looking into one of these lathes. The lathe is on sale and I think you can even get free shipping. I am hoping that our team machine shop will get one before next year to replace the only worn out 1900 vintage Hendey lathe we have now.
Always keep in mind that the machines are only half the cost. You will probably spend at least as much on tooling (collets, vises, end mills, turning tools, etc.)
OK, this is going to take a while… First off, there are already some good discussions on these topics here and here. My comments below are updates of some of this information.
Based on the phrasing of the question, are we correct to assume that you are not asking about what one might consider “traditional” shop equipment such as bandsaw, table saws, drill presses, etc, but are particularly interested in metalworking equipment? Assuming so, we will stick strictly to the latter. With that, the recommended list would be:
6. Mill or beefy mill/drill
7. All the tooling you can afford for the above two items
8. Metal-cutting bandsaw
9. Digital Read Out (DRO) for the above
10. CNC upgrade kit for mill
If there is only one metalworking tool you can afford, you have to start with a lathe. I recognize that this opinion is contrary to the earlier posts, but I am adamant about this one. Starting with this one tool you can, given sufficient time, raw materials, and some basic machining skills, make every other machine tool you will need (in fact, that is how apprentice machinists used to learn - by making their own shop tools, up to and including building new machine tools). There is a great series of books on this by Dave Gingery, if you ever have the time. And with a vertical X-Y table mounted to the cross-slide, you can perform most basic milling operations on the lathe. You will not have an equivalent capability to perform turning operations on the mill (yes, it is possible, but it is not as easy).
Next, look at your budget. One of the fundamental truths associated with buying any machine tool (mill, lathe, shaper, surface grinder, etc.) is that the associated tooling will cost as much - if not more - than the basic tool itself. So if your full budget is $5000, you need to be looking at lathes and mills that are in the $1000-1500 range per machine. So right from the start, you can eliminate anything like a brand new Bridgeport or large free-standing model. You are in the range of a bench top mill/drill, or a bench top mini-mill, or maybe a used floorstanding machine (if you are willing to put in the time to refurbish it properly). Buying your lathe or mill is only the beginning of the investment. Unless you know how (and have the time) to make all your own tooling, plan on spending AT LEAST as much as you spend on the lathe/mill for the additional tooling you will need. For the lathe, things like backplates, 4-jaw chucks, cutting tools, tailstock chucks, free centers, collet sets, tool post fixtures, center indicators, tailstock die holders, cutoff tools, tool post grinders, knurling tools, etc. all add up fast. On the mill clamping kits, cutting heads, mill holders, rotary tables, tilt tables, boring heads, edge/center finders, etc. will also create quite a dent in your wallet.
Many of the lathes and mills sold by Grizzly, Harbor Freight, Enco, MSC, Smithy, and others as “their” brands really all come from the same sources, and they just stick their labels on the machines. Most of the lower-end lathes and mills come from either Taiwan or China. Find out where the machine was made - there is a BIG difference in quality. Many of the Taiwan imports come from Rong Fu, and are good, solid machines (high quality castings, good precision on the ground surfaces, solid pulley/gear covers, etc.). Many of the Chinese import machines tend to be copies of the Rong Fu designs, but with lower quality (blowouts in the castings that have been filled with Bondo, flat grinding on the lathe ways with no oil-retention scraping, cheap sheet metal covers, etc.).
Once you start looking seriously at machines, look for and buy the largest capacity machine you can afford. If you think you only need a milling machine with an 8x24" table, but you can afford one with a 10x36" table, always pay the extra price and get the larger one. Fundamental truth number two is “the largest piece of material you have to machine will always be two inches larger than your machine can handle.” A large machine can always work on small parts, but the inverse is not always true. Even if you can’t think of anything on your robot that will need a big capacity machine, you never know what you will want to work on during the off-season or next year. The reality is, bigger is better. Get the largest lathe and mill you can afford and fit in your shop. The larger machines will have larger chucks and spindles, hence a larger rotating mass during cutting operations. The larger rotating mass acts as a big flywheel, making for smoother cuts. The larger machines also provide more rigid support for the tool post and tooling, reducing chatter.
Make sure you know (or can find someone who knows) how to set up the machine. It is not as simple as opening up the crate and tossing it on the stand. The lathe has to be mounted on a VERY solid support (think about really big slabs of concrete, or at the very least a really heavy workbench), and preferably bolted to the floor. To get good performance and precision, it must be very accurately leveled in all dimensions. The lathe bed needs to be checked carefully for twist and spindle alignment. The mill table needs to be leveled and the head trammed in. This is a straightforward process if you know what you are doing, but probably not something you want to try alone if you have never seen it done before.
Similarly, you need to worry about maintenance of the machine as well as the set-up. Is the manufacturer still in business and/or is there a distributor network for spare and replacement parts if you need any? Is the tooling interface a standard size, so tooling will be readily available and inexpensive? Will you have access to other people that have used this make/model machine that you can turn to if you need help? Time for fundamental truth number three: “when your made-in-the-USA machine tools breaks, the part needing replacement is the one piece that was manufactured by a defunct company formerly located in Eastern Slobovia in a factory that now produces shower curtain rings. Your custom-made replacement part will cost more than the original price of the whole machine tool.” Having access to a bunch of other owners of the model XYZ mill will help you find sources for these replacement parts (one great resource is on-line user groups - check Yahoo.com for “model XYZ mill users” or whatever).
If you have someone on your team that knows what to look for (any retired - or active - machinists on your team?), consider buying a used lathe and mill. If you know what to look for and can avoid getting scammed, you can get some great deals on used machines. I picked up the 12x27" lathe that I have in my shop as a used machine for 20% of the original purchase price, and all the basic-to-moderate tooling came with it. I knew the person that owned it, and knew the entire history of the machine, so it was a good deal. eBay has some nice deals, but be sure it is a machine that you can inspect before final purchase.
If you can, get a lathe with a quick-change gearbox. Most of the larger models have them (typically, anything over a 10-inch swing and/or 30-inch bed will have them). You will save yourself lots of time and frustration associated with dealing with change gears if you get this option (and save a lot of re-training time as student operators change from year-to-year; it is a lot faster to teach someone how to use the gearbox than it is to teach them how to change the gear sets). Same thing for the lathe tool post - get a quick-change version if you can, and one that allows easy adjustment of the tool height. It will make life much easier.
I know I will get some disagreements here, but I recommend you stay away from combination machines (lathe/mills, lathe/mill/drills, etc.). In my experience (and that of a lot of people I have talked with), these machines are designed to do too many things and to cost too little for the careful design they really need. As a result, they don’t do anything really well. I have never been happy with the accuracy or precision of any of the combination machines I have used.
Since you specifically mentioned the Grizzly 3102, it is worth suggesting that you also look at the Rong-Fu model JF-45. It is the source machine for the Grizzly 3102, which is basically a copy of the Rong-Fu design. Note that in the U.S. many of the directly imported Rong-Fu machines are re-labeled as “JFC” which is their primary U.S. distributor. It is in the same price range as the Grizzly model. They use R-8 tooling, which is commonly available. There are several on-line groups (such as the Yahoo Mill-Drill group) that are very active and helpful. If you go this route, be sure and look for the Rong-Fu model, which is made in Taiwan. They are good quality machines, apparently made by a company that still gives a crap about quality and tolerances. Problem reports on them are infrequent. There are several makes of Chinese knock-off copies, most of which have real problems ranging from sand-filled castings to skewed table ways to horrible backlash problems on all axes. Avoid them like the plague. Enco, MSC, Grizzly, and Penn Tools all have carried both original Rong-Fu machine tools as well as the cheap clones - if you buy from any of the re-market distributors make sure you know which version you are getting.
There are lots of on-line resources and discussion groups you can use to find out more information and get a lot of help (both before and after you buy). Here are a few resources to check:
7x10minilathe - Yahoo Groups board for owners of the Chinese 7x10 minilathes marketed by Harbor Freight, Grizzly, etc.
9x20Lathe - Yahoo Groups board for owners of the imported 9 x 20 Lathes sold by Jet, Enco, Harbor Freight, and others.
Bench Mill/Drills - Yahoo Groups board for owners of metalworking mill/drills made by Rong Fu and the knock-off clones (but includes a lot of discussion on lathes as well)
Thanks for the lengthy and detailed answer Dave. And thanks for the answers everyone. Keep them coming.
The machining equipment Harbor Freight sells comes from various manufacturers. Is any of it good or okay quality? If so, which exact model(s)?
Also, I’m guessing we cannot make parts which need a bigger area of machining on the Y axis bigger than the Y travel allows for. Is this right? So I’m guessing a Y travel of something like 6" won’t be enough for some common robot stuff.
Are there any small turnkey CNC mills out there in this price range? The MaxNC ones are but they don’t seem powerful enough.
In any setup, how do you deal with backlash? DRO? How much would DRO be on something like the Rong-Fu mill?
I’m not sure as to the size limitations of your machining capabilities, but in starting a team this year with a converted copy room and a $700 total tool budget, here’s what we opted for:
Delta Shopmaster 9" bandsaw ($99)
Delta Shopmaster Table top Drill Press ($99)
Delta Shopmaster 2-Wheel Grinder ($59)
All of the Delta products have served us very well so far, and one of the biggest advantages is that we can have all 3 machines creating totally different parts. When considering a combo, I think it is important to note that there is a high potential for a wait-list…everyone waiting to have their part made from the same machine.
Now, assuming that you aren’t starting from scratch, is your team held in a high school? With many school districts/states eliminating technology classes, there are often older but still maintained machines that are sitting dormant in another building. A team I was previously a member of got a full vertical mill as well as a lathe for free…we just had to politely ask the principal and then superintendent if there were any machines that could be transferred in. It’s always worth a shot, and you might luck out by getting something for free…
A couple of years ago we got a Smithy 3 in 1 and it suffices for most of the jobs we do - but the cost of tooling is significant, and we have now spent 2x the amount of the mill on the tooling (Rotary indexer, 4 Jaw Chuck, clamps, Vice, indicators, cutters, boring head, and the Digital Read Out).
Last year we got a grant and purchased a small benchtop CNC by Microkinetics and when I say small, I mean small. But we use it now a lot to make mounting plates for motors or transmission plates where the mounting holes need to be tight in tolerance or if you need a .498" hole to press fit that bronze bearing etc… The max piece it will mill is 3.75" x 7". So we often use 4" bar stock or smaller where the cuts are no more that 3.75" from one edge. It’s faster for students to learn to use than all the components needed to make the same part on the manual mill. We write our own G-Code, but you may be able to get MAsterCam donated, although you end up spending more time in MasterCam than just writing the code yourself.
The CNC cost came to about $4000 and there’s not a lot of tooling you can get for it because of its limited size (we just have a couple of endmills of diferent sizes like 1/8", 3/16", and 1/4"). Just a lot of patience with it as it only takes off .05" with each pass and you have to clear the chips out of it with a shop vac constantly.
I included some pics of parts we made this year on the CNC. I don’t mean to let this thread get off topic, but I think its unrealistic (not impossible) that you’ll get a mill or lathe up and running for $5000. Other dire shop tools are a horizontal band saw (~$200), Drill press, and don’t forget how useful a disc/belt sander is also.
Everyone should take 5 minutes and really read Dave’s post above from start to finish. Those are very wise words from a very wise man. I second everything he said in the post including the negative remarks about combo machines except for the first 5 items on his list. While I agree that for most machine shops the lathe should be first and that you can make any tools you need with a lathe, I personally, think a mill would be #1 on the list. As an apprentice machinist it would be very instructive to “build your own mill” from a lathe, however, I don’t think that level of instruction is required for most FIRST teams. Our team has access to both a (very old wornout) mill and a lathe and while we use both because we have them I think we could get by better with just the mill than the lathe. We tend to make more “flat” things like brackets with slots or counterbores than we do “round” things other than shafts and spacers. Any of the shafts and spacers we have made so far this year could have been made with a hand hacksaw and squared off to length on the mill using a vise or v-blocks and an end mill. It would have been much more difficult to cut a keyway along the length of the shaft with only a lathe. The counter bores could be done on either the mill or the lathe but the mill took much less setup time. While it is possible to do some pretty nifty things on a lathe only if you also have a 4 jaw chuck and a compound mounted vertical x/y table it is just so much easier on a mill. To each there own, that’s just my opinion. The bottom line is either way if you get a lathe then about a week later you will want a mill and vice-versa.
Another bit of advice when purchasing a lathe is pay attention to the spindle bore. The larger the bore the larger diameter material you can poke through and work with and the less you have to rely on a steady rest farther out from your chuck.
You probably want to stay away from the 3-Phase power units.
Again, there are other places that sell the real Rong-Fu or lesser quality knock-offs including Enco, Grizzley, Wholesale Tools, and others.
So for your $5000 you should be able to get EITHER a nice benchtop Rong-Fu mill/drill and tooling OR a benchtop lathe and tooling but probably not both unless you went with the small 7x lathes and mini-mills from Harbor Freight, etc. or found some good used equipment locally. Just don’t underestimate the cost of tooling and accessories.
Mr. Lavery, do you have any opinions on the JET line of these benchtop mill/drills and lathes. Are they good quality or in the cheap knock-off category? I have no experience with JET tools and am curious. Examples: JET mill/drills (bottom 3) and JET Lathe. The JET mill/drills seem more expensive than the comparable real Rong-Fu RF-25/31 mill/drills but the lathes seem pretty reasonable price-wise. I am just wondering about the quality. Our machine shop sponsor is looking into getting one of these JET lathes before next season.
Also, can someone explain to me the difference of round column versus dovetail column? I’ve only used old large bridgeports, no small machines. I read somewhere that on the round column if you move the Z position you lose your X and Y position. This isn’t true is it?
Also, are there any mills already equipped with DRO or any inexpensive DRO packages.
I saw a Jet full size mill (sits on floor) with DRO for $3500 that seemed attractive but that’s a bit out of our price range.
If we bought machining equipment, we’d probably want a mill and a lathe. Although I’m guessing the lathe capacity wouldn’t need to be so large.
Oh no! That mill/drill is not a true Rong-Fu but one of the cheap knock offs that Dave was talking about in his lengthy post above. It is far less quality built and will likely have significant backlash in the leadscrews and pretty poor castings and an uneven table. You would be much better off with a used mill than one of those.
Yep that’s true, more or less. A round column is like a drill press. You know how when you move the table on a drill press up or down on the column it is almost impossible to get it exactly the same? It is the same on a round column mill/drill. A dovetail/square column mill drill allows the distance between the table and the head to be adjusted without loosing the setup alignment.
Would you be inclined to make one yourself? Check out the Shumatech DRO-350. There is also a Yahoo group for the Shumatech DRO-350 project. Do a little research about it and you may be surprised. It’s a pretty neat project if you are so inclined.
i agree with the person above me on this one. I dont know brands off hand but i do shop @ harbor frieght often <happy>they just opened one 15 mins from my house</happy> and they are great for small tools and other hand tools for the team but large tools that would be used often and take much “abuse” (not in a negative way but just use) will wear out quickly. So stick to a more reputable brand what ever you choose.
I can’t speak for their metal working tools, but I have their JWBS-14MW 14 in wood/metal (3-speed) bandsaw and am quite satisfied with the quality of the machine. It compares well with the better Delta machines. The castings are solid and true, and the adjustments are easy to use and stay set pretty well. The included accessories (fence, square) are cheap, though.
We went with 5, why? we found a great deal for a very un-worn bridgeport (nearly pristine) with a good DRO, power feed, full set of precision collets. With a vari-speed head.
IMO the X2 has serious rigidity issues, but its good for whatever work FIRST requires (±2~3 mil) and you can take it to regionals (reasonably)
X3 is much better, more rigid, and people have supposedly held mil tolerance… so I guess its pretty good there
the ZAY and IH are by the same manufacturer, the IH is just HUGE and has hardened gears, as well as a CNC option. the free shipping also makes it worth it… we were about to go with the IH mill when we found the bridgeport deal.
Honestly, just pick a dovetail column mill, its more rigid, doesnt need re-center every time z is changed… or a knee mill (better, but more expensive).
Also, I’m not sure if used equipment is the best way to go… fixing the machine can be as much of a challenge in and of itself…
As you know, the first Hawaii regional will be held next year. In preparation for the event, we are investigating what it would take to build a mobile machine shop. While we can always use the College of Engineering’s machine shop, a mobile shop at the venue would be a lot more convenient for the teams. With that said, does anyone have any suggestions for equipment?
I figure we need at least the following:
Bench Lathe (9"x20", 12"x24")
Bench Mill (Round or Square Column with DRO)
Welder (TIG, Mig or do we need both?)
Also, could someone from team 254 give me some insight about the NASA Ames Mobile shop? perhaps some pictures. How about other mobile shops? Have these machine shops been able to serve most teams needs? For example, I think the Ames shop has a 9" x 20" Jet bench lathe. Looks a little small, but if it provides what teams need at the event, then small is good since this will be a mobile shop.
Model numbers and where to buy would be greatly appreciated.