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Rank: Newbie
Groups: Member
Joined: 12/9/2009
Posts: 3
Points: 9
Location: Kansas City
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First off.... Thanks for this great site. I have learned a great deal just by reading through here and I actually feel like this is something I can do now. Trying to piece it all together from forum posts is pretty difficult. This site has been very helpful in getting it pictured in my head.
I've ordered the 44991 through Harbor Freight and I plan to work on improvements as my budget allows. Since I dabble a bit in electronics I'm probably going to build my own 3 axis controller/driver for it. When it comes to metal work however I am a total newbie. Never run anything beyond a Dremel. This all ready sprang up from the desire to be able to cut custom panels for my electronics projects in plastic housings. Cutting out large square openings for LCDs, or other more complex shapes and having it look nice is not easy or real practical with hand tools. Also the ability to mill some PC boards would be a nice benefit later down the road with CNC.
I am hoping I can make many of the needed parts for the conversion using the mill manually. A couple of things come to mind though.
1. I have no lathe nor will I have one any time soon, space and budget won't permit at present. I was wondering how far I can get with a rotary table on the mill to re-profile basic cylinder shapes? Is that even feasible? Seems as though it should be. I'm not planning to make chess pieces here, just reduce diameters and other simple stuff. In other words, can I limp along without one?
1a. Is it feasible to mount the rotary table to cut that part off the rough stock? Seems like it should work.... slowly.
2. Should I plan to go to ball screws even while still manual? I have read that you shouldn't someplace but it doesn't make sense to me.
3. Work holding.... there is a dizzying array of stuff, vises, tables, clamps, blocks. I am thinking of getting a 3 or 4" vise but wondered if I should get something else based on others experience?
4. Other tools? For tools beyond the mill I have:
- Digital Calipers
- Power drill
- Dremel
- 7" Angle grinder
- Hack Saw
What other tools would be essential to have?
5. Books. Any really good books to cover the basics of working with mills/lathes/ect?
Thanks for any help, tips, or info you guys can provide!
-Kyle
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Rank: Administration
Groups: Administration
Joined: 6/28/2008
Posts: 215
Points: 407
Location: Follansbee, WV
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Hey Kyle, welcome. CNC is fun but give yourself some time, there's a lot to learn. 1. a rotary table is not made to spin fast, gearing is usually 36 or 90:1 for turning like on a lathe you would want 500 rpm to get a decent finish so you would have to spin the rotary table crank at 18000-45000 rpm. No way it will handle that, a lot of them only have bronze bearings. It is possible to use the mill spindle to hold small diameter parts (2 inch) and use a lathe tool clamped to the mill table to turn the part. This can be done manually or under CNC control later for some complex shapes. You can also make a lathe attachment like I did for larger work. 2. ballscrews dont work well for manual milling, they are very efficient and have little resistance to turning which could lead to the endmill pulling itself into the work on it's own particularly when climb milling. It's possible to "ride the brake" and snug up the gib locks a little to give it some resistance but it's not ideal. 3. A decent 4 or 5 inch vise and a clamping kit will get you going and take care of most work holding. 4. Little Machine Shop has a guide for selecting tooling that could help. A socket set, drill bits and a tap and die set will be valuable. 5. LMS also has a good selection of books and videos at good prices too. Hoss
Gosh, you've... really got some nice toys here.-Roy Batty
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Rank: Member
Groups: Member
Joined: 9/27/2009
Posts: 12
Points: 36
Location: Hollister, CA
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Aloha Kyle,
I just started in with the HF44991 myself. After a bunch of lurking, I decided to go the road of the Gecko G540. It's a breakout board, 4 motor controllers, a VFD (you'll learn about that soon enough...) all for about $300. Motor controllers each can be $100-$150 each. I can't do math in public, but to me it seemed to be a no brainer financially. Down side is that you are somewhat limited in other inputs and outputs, but there are more than enough for a 'basic' machine with a few bells and whistles; just no rocket launcher attachment or pitot heat.
FWIW, after getting the mill, I ordered a set of collets from LMS. A week later, I ordered a 4" precision vise (the HF one was a complete POS). A week after that, I ordered the 4" rotary table for making the 1.380" hole for one of the stepper motor mounts. I was fortunate enough to rummage through a box in a buddy's hangar that had a pile of old end mills so saved some bucks there.
Before I found this site, I looked at fignoggle.com for a bit and bought their conversion plans and DRO plans. After comparing those CNC plans to the drawings available on this site (free BTW. Thanks Hoss...) I decided to pitch the fignoggle plans. The DRO plans were mostly correct and are a good way to start making chips so I kept those. DRO's on fleabay will help get you stated and take the guesswork out of the manual machining.
As for books, the ABC's of CNC was entertaining, and mostly worth the $'s, but I got more out of the CNC cookbook. I recommend that one...
As for as machining goes, once you start making chips - you will REALLY start learning.
As far as websites, look here, cnczone.com - bench-top machine section, littlemachineshop.com, lathemaster, fignoggle... each one brings something unique to the party.
Good luck!
-4ist
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Rank: Newbie
Groups: Member
Joined: 12/9/2009
Posts: 3
Points: 9
Location: Kansas City
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Thanks for the welcome and info guys!
Forrest. I do understand that I could likely purchase the drivers for less than the cost to work up my own but I am planning to see if I can make a useful product that might be sell-able. My plan is to create a 3 axis controller that can run stand-alone or via computer control. I'm hoping to be able to get it to where it could take an SD card with G-Code and run that. It would also be able to drive the system to a specific position based on input from a keypad. I tinker in this stuff so it's just fun to play. Soon I will have the ability to make my own PC boards and with that the cost of building some simple drivers on the SLA7062 would actually be quite low.
Thanks for the book recommendations. I will check into those.
I am still am a bit confused on the rotary table. I read that they are used to mill circular features into parts, pockets, shoulders, rings, ect. So I'm not seeing why if they can do that they can't just complete the circle and reduce an outside radius a bit like a lathe. I wasn't envisioning spinning the table as a spindle, just using the table to let the mill cut down the outside in a pinch.
Lastly I have one more question. Assuming I can ever find a place to put a lathe there will certainly be no room for a metal cutting band saw. Is there any compact substitute for cutting solid stock. Hack sawing through it sounds unpleasant and untidy at best. Using an angle grinder and cutoff wheel for several inches of solid bar metal is frightening. A chop saw looked like it might work but I was wondering if there are any blades that would allow a heavy duty miter saw to work? If I could buy a power tool that would be useful on wood too it would help justify the cost a bit more.
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Rank: Administration
Groups: Administration
Joined: 6/28/2008
Posts: 215
Points: 407
Location: Follansbee, WV
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You could use the rotary table that way in a pinch, just be a little rough looking. I used a portable bandsaw for a while. http://www.hossmachine.info/fun_stuff.html#bandsawYou can use a carbide toothed blade in a mitre saw if you be careful, just for aluminum or softer. I tried it once and it's... unnerving. Someone makes one, I forget who, that turns at a much slower speed for cutting aluminum. Hoss
Gosh, you've... really got some nice toys here.-Roy Batty
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Rank: Newbie
Groups: Member
Joined: 12/9/2009
Posts: 3
Points: 9
Location: Kansas City
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Ha! The portable bandsaw contraption is perfect. A vice and a small table I can do!
I was thinking the same thing about the miter saw. High RPM blades and thick metal make me nervous. No workman's comp in the garage.
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Rank: Administration
Groups: Administration
Joined: 6/28/2008
Posts: 215
Points: 407
Location: Follansbee, WV
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Found one of the metal cutting mitre saws, they even show it cutting steel. probably has a lot to do with their blade. Several videos shows it working though the metal they cut is really no thicker than 1/4. http://www.evolutionpowertools.co.uk/us/evolution_rage3.html#Hoss
Gosh, you've... really got some nice toys here.-Roy Batty
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