CNC a Harbor Freight 33686

Craigslist find, from a tool and die maker. A 1984 Enco RF-30 ( for $600.00) with the Rong Fu Z axis gear drive. The HFT 12 speed unit is a virtual identical copy, sans the Z axis drive.

This has a single phase motor wired for 120 VAC, that gets quite warm after 5 minutes. No reverse. So, upgrades will come along slowly... First is that the missing Z axis drive belt is available on ebay, so ordered ($12.00?) and installed it. Cleaning up and lube was second. Then, thought of rewiring from the 120 VAC 32 Amp to 230 VAC 16 amp, with a drum switch to provide reverse... But, have acquired a 3HP, 2.2KW Marathan VFD 230 VAC 3 phase four pole 1725 rpm motor, ($50, on Craigs List, in the mounting frame, with the variable belt pulley! That pulley sells for over $55, new!), and, with the variable width belt pulley, will use the 23/32nd inch width belt, and, a VFD box, such as this:
http://www.vfds.in/3-hp-vfd-single-phase-to-three-phase-vfd-260617.html

Your experiences and input will help me greatly! A question is have you done this? Would it be better to get a more powerful VFD electronic drive machine, such as one for a 4 HP 3KW motor?

Oh, he included that huge US made machinist vise, two sets of clamps/dogs, in their storage frames, two fly cutters, small and the big one, with 8 bits up to 6 inch, complete set of three chucks on R8/M2 shafts. Most are US and/or German/Belgian made, for an extra $200.00.

Yes, there are great bargains to be found! I have been an electronics engineer, Air Force trained, 1965 to 1985, taught AC power for installers, in GEEIA, and have been a commercial welder on the FMC plant lines. I am an FCC licensed Radio Amateur, rebuilt computers and set up private class rooms for latch key kids, in several schools, since 1997, running only the Linux and the BSD operating systems.

So, next was to order the speed indicators, which are LED readouts, with magnetic sensors, that sell for about $4.00 on ebay. I have 9 volt 100 ma
DC power transformers to power them. Then, will be installing Digital Read Outs on all axis, for best accuracy, though initial set up of the vise and column, will be with the 1" dial indicators on magnetic bases. Last but not least is to eventually install stepper motors and CNC read outs.

Thanks for this opportunity to learn new things!
 
I've built a number of CNC machines and converted a couple of mills. If I already owned a round column mill I might try it, otherwise nope. Not that is can't be done, it's just a lot more trouble to get the z functional. Converting a mill to CNC isn't that hard and I would say anyone can do so if you have the right tools and are willing to invest the time. Buying a kit is the fastest and easiest, but fabricating it yourself is a great project in my opinion. While the manual mill is operational, many of the parts can be fabricated using it. Depending on your mill and the parts used you may have to do some mill work on the table (pockets or material removal to allow room for ballnuts, screws etc) which would require a different mill or hand grinding. Personally I'd do a bit of research on the web for cnc conversions folks have done on mills in your size/spec range and then decide which mill and conversion approach to take. I've seen lots of conversions on the HF mini mills as well as little machine shops version and of course a myriad of Grizzly, PM's and other imported models. Once you decide, you should be able to find and buy a used one as your conversion guinea pig. With some of the commonly converted models there are parts like pre-cut screws with the ends machined or motor mounts etc that allow you to mix and match what works best and fits your budget. Same goes with you electronics. You can piece together your own, or buy complete or partial kits. 570 oz nema 23 steppers are fine for smaller mills, but nema 34 and larger steppers or a servo motors are always an option. If you have another mill and a lathe, machining and fabricating everything yourself won't be hard. This place has about the best prices on components and kits unless you'd rather find individual parts on ebay or elsewhere on the web. https://www.automationtechnologiesinc.com/
If you have any specific questions feel free to pm me.
 
Yes, that kit will likely work just fine. I use the same motors, drivers and power supply on a couple of CNC machine I have. I've bought a couple of their 3 and 4 axis "kits" and haven't had any issues.
Round column mills are by nature of their design a bit more challenging to convert to CNC. A round column mill will lose it's Y and Z zero reference points when the head is raised or lowered during tool changes. The head is not indexed to the column so can rotate causing alignment issues. Your Z is limited to the quill height/travel distance. On the square column mills the head rides in in a dovetail with adjustable gibs just like the table does. There are a few work around's, but I personally have never CNC'd a round one so not sure of the results. Other than these issues, they are solid machines and with a little pre planning you can work around most issues during use. If you're already looking at electronics I'm assuming you likely know more about converting the 33686 than I do. Don't let the electronics intimidate you. Once you get into it and get it going you'll see how fairly simple the electronics setup is.
Have fun!
 
Thanks for your reply! It is hard to keep from being intimidated by the electronics (for me), but want to build. It's the rest of the electronic stuff that gets me. Power supply, drivers, etc. As far as the mill, I am very aware of the limitations of the round column, but have no issues as I had one for several years a while back and just had or made tooling to use for the job that worked without having to move the head. In that respect, a good machine.
 
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