It’s that window shopping time of year for me, as I spec out various tools for potential purchase. One of the items I’ve been eyeing up for a while is a benchtop mill/drill. Due to the power restrictions in our primary build space, we only have 110V available to work with, so most full-sized knee mills are off limits to us as they typically require 230VAC. Additionally, we only had a single doorway, so full-sized knee mills may not even fit into the room without major dissassmebly.
Does anyone have any particular reccommendations for 110V mill/drills? R8 collets and the ability to add a DRO (or DRO integrated already!) preferred.
JET seems to have several viable options, including many available via Amazon.
The Rong Fu rf-45 is a good fit, though genuine articles are not inexpensive. Real ones are made in Taiwan and are generally well cast and assembled machines. Clones are common and range from fine to garbage.
An important factor in this sort of machine is a square column. This class of machine will have very limited quill travel so moving the head up and down with tool changes is typical. A square column ensures you hold something like a zero when doing so.
It also has the critical R8 taper spindle, a gear box and 120v compatibility.
Rf-45s and their clones have excellent aftermarket support, with a lot of options for DRO, CNC, VFD and other upgrades.
We have a bunch of JET tools in our shop. I’d have to look at it to confirm, but I believe we have an older version of this mill, purchased in 2013. We’ve been pretty happy with it, only having one real issue so far (caused by mentor stupidity). We’re at the point where it’s running practically the entire time every meeting during the build season.
We’re not as happy with our JET lathe, though. We’ve had a heck of a time working out some of the slop and getting tools to properly locate. It works, and honestly, I doubt the students even notice any issues… but it’s something that really bugs me and one of the other mentors.
the rongfu-45 with square Z column/dovetail is the key to usability. and I wouldn’t get anything small like a LMS 3990 with tappet gibs. go one step higher to a grizzly g0704 with the tapered gibs at least.
repeating my comment on the round column Jet, and agreeing with Dave, I wouldn’t get it if I had the choice, but I’m glad we didn’t throw it away because we got a lot of use out of it by fixing the Z column and NEVER using it in the “drill” configuration (for the extra working height needed to use a drill chuck) for the reason Dave mentioned (I’m pretty sure he’s talking about his experience with the same mill…), we just used short drill bits in the appropriate collet. and built a lot of robots once we did that.
knee mills can be broken down, x travel bed and head removed and rebuilt, if getting it thru a standard door is the only obstacle.
but yes, the space required for them is overall unwieldy for its purpose compared to a benchtop mill/drill. kinda just went thru that mental exercise of “do we have space for that?” recently ourselves…
+1 to router, but on the subject of mills:
I’ve heard good things about the 6x26. They’re not all that large, and knees are super nice.
If you have to get something smaller, 100% get something with a square back. Round column mills are near-unusable.
The door is one challenge, but so it moving it from the loading dock to the room through the school. Simply put, the classrooms we work out of are in about as inconvenient as possible a position to receive something that large.
We’re also running out of space for larger, floor standing tools. Our build space also functions as a classroom during the school day, so the power tools largely have to hug the walls of the room.
We do have a 110VAC router, albeit underrated for cutting aluminum. We still get some mileage out of it on polycarbonate, and have parallel efforts to acquire a Omio X8 ongoing. However, due to the nature of this particular funding, we’re investigating purchasing something from an American vendor that honors school’s tax free status. The Omio will happen at a different time with different funding.
A long time ago, we had one of these 110v mills from grizzly or someone - was actually pretty decent with DRO and a power X feed. We brought it into our space through a standard 30in door from the loading dock on the far side of campus with the help of a cheap engine hoist from harbor freight.
Big thing on the LMS machines in general is that you need to keep an eye on them for signs of slop/wear, but if you keep them maintained they’ll keep on trucking for quite a while. They’re also relatively inexpensive… You get what you pay for, and maybe then a little bit. I don’t have any experience with the mills from them but I’ve worked with several of their lathes.
Can confirm, you can fit an entire 9x42 Bridgeport through a 30" door frame.
Moving them wasn’t that bad, as long as you had a bunch of steel pipes / rods to act as rollers, a good come-along winch, and some good 5-6 foot rigging prybars. Once you got it onto the steel rollers, moving them through the school/shop was pretty easy.
The only concern would be if multiple floors were involved without any ramps.
If a full size or smaller knee mill or RF-45 sized benchtop mill is not an option I would recomend looking at the Sieg SX3 benchtop mills.
I have personally owned one for the last 10 years in green branded by Grizzly, their G0619. Within its limitation it is quite capable and accurate. the addition of a DRO and appropriate tooling and you can make almost any small parts that an FRC robot could need. Last year I even made a few custom extra long hex output shafts for the versa-planetary gearboxes.