[Jason Marsha]

Faced with the prospect of scratching out my missing aluminum motor mount on a very small CNC machine, my progress on the Bridgeport had stalled. Having a very busy life made this little excuse enough to delay any effort.

Then I had a breakthrough -- a few simple realizations that were enough to get me motivated again:
1. This part really doesn't need to be aluminum, or even acrylic. It's under very little stress.
2. I can cut the part from MDF and have it done in an hour or so!
3. The design of the bracket is already done. All I need to do is make it.

Cutting the part from aluminum would take a long time: 6+ hours on the small machine available! I also could not find a suitable piece of aluminum stock to cut the part from. That was enough of a mental barrier to keep me from attempting the build. I had "builder's block!" You know, like writer's block. And so the project sat.

The idea that I could have the part in my hands in an hour changed my electronic design into reality. It was very satisfying to make chips again, even if the chips were really just MDF dust. The part bolted up perfectly, toleranced just right for a snug, but not permanent fit with the locating circle on the NEMA 42 servo motor. The bracket can also accept a NEMA 34 motor, if I need to change my mind again.

Another nice discovery -- the bracket fits! Someone asked me for the CAD models of this design a few months back, but just before I sent the models, I realized that the "star" points of my design would probably interfere with the vari-speed housing on the spindle! So I didn't send the models, thinking the design needed more adjustment. If you're following this thread and still interested in the IGES or Pro/E models, please PM me.

Of course, there is a new stopper: My helical coupling fits a 1/2" motor shaft, which is what the NEMA 34 motor used. But the NEMA 42 motor needs a 5/8" coupling. Fortunately, McMaster Carr has good prices and I was able to order one online. Hopefully it will be here on Tuesday. If you want to take a look, go to www.mcmaster.com and type in "6208K14" which is the P/N.

I designed a similar plate for my diy cnc router a while back but then decided instead of the star I cut it as a circle.

PS. I think your garage is fulllllll.

Jason

[Barry_ward]

Yup. First thing you tend to want to do as you transition from a manual mill to CNC is preserve old habits and keep the handles. "the feel !"

There is no reason whatsoever to have handles on a mill. I'm not really a machinist. I don't know much about it, other than the results that I wish to achieve. When the manual mill starts chattering, you back off. When you start a job and are unsure on your CNC, you just go slow. You can always change the feed rate. Since it's more consistant than you will ever be when you crank manually, you can observe the results and change accordingly.

For irregular milling jobs that have a "I really just want to throw this in the vice on the manual mill feel", I just set a 0,0,0 reletive home location and jog at a rate that I think will work. As I get close I just slow the jog or use incremental jogs and record the endpoints. Then I can just enter the Gcode manually at a few thow closer and repeat the path to get a sweet finish cut.

Sometimes I use the MDI line to go to my endpoints. MDI has helped me get better with Gcode as you tend to be careful before you hit enter.....

I've also drilled quite a few holes in almost every type of material using a hand drill and drill press. I've never felt as confortable as when I have a part clamped on the CNC mill and just drill at a good feed rate. It's sweet and produces a much better result at exactly the location that you want. Even better still is that you can just go back to that location and tap the hole too.


Barry

[wddanie]

Can you give me some details on the Emerson drives you used on this retro? Why did you choose them over the Gecko 320 step to servo drive?

Thanks,

Doug Danielson

[unterhaus]

Can you give me some details on the Emerson drives you used on this retro? Why did you choose them over the Gecko 320 step to servo drive?
Thanks,
Doug Danielson

He's using brushless motors, and thus the Geckos will not work.

[damae]

The winter is my busy season at work and it's hard to scratch out enough time to make progress on my machine. But it seems there is still interest even without progress! Thank you guys for sticking with me =)

Jason: Nice motor mount! Your design yields a much better bang-for-the-buck! And yes, you're right -- my garage is .. uh.. loaded! I'll be working on that clutter problem as the winter yields to dry/warm weather and I can open the garage up to reorganize.

Doug: Unterhaus is right, my motors are 3 phase AC brushless, also made by Emerson. In fact, these motors really are not designed to run with any other controller than Emerson. They use resolvers instead of encoders, making them pretty picky about what controller drives them.

I like overkill! Really, I used the Emerson motors/controllers just because I found a good deal and was fortunate enough to buy working units. If I had to do it over again, I would likely go with Rutex or Gecko drives.

Barry: You and I are thinking along the same lines. I put my mill to limited use cutting while in jog mode. But like you, I find that DNC is the just about the best way to do really controlled cuts. As I get better at hand-coding, DNC seems like the best way to do "manual" machining on a CNC. I saw your pictures of CNC tapping on your Shiz -- very nice! That is a long way off for me, but certainly would be nice to have!

[wddanie]

I just bought a AN-S Shiz with a dead Bandit control and am planning the retrofit. I see you have one, so what are your plans for its controls?

Barry and I live about 20 miles apart, so I drove up and looked at his Shiz, which gave me the confidence to go ahead and bid to win the one on ebay.

Thanks,

Doug Danielson

[damae]

Hey Doug, welcome to the retro club!

The AN-S is a really solid machine. They are well built and retrofit friendly. Technically, the Bandit controller was a retrofit. So I'm doing a retro on a retro!

So the rough plan looks like this:

Mach3 for front end
GREX for motion control/breakout
Reuse original servo motors + new encoders
Gecko (or Rutex) for motor amplifier
Build my own power supply (I have lots of surplus toroids)
Rebuild motor mounts
Build new control housing

Since the Shizuoka is the last machine on my retrofit list, presumably I'll be making less mistakes by then. I'll have to invent new kinds of mistakes! For instance, I've never botched a toolchanger retrofit before, and I keenly anticipate doing so! The toolchanger is pretty messed up on my machine, so It may never work properly again. For sure it will require reinventing and redesigining some of the basic mechanical components, like the tool grabbing arm.

Barry is just finishing his first-class retrofit, so I'm sure you will be able to learn a lot from looking at his project by seeing it in person. I wish I had pressure-washed my mill before I got it in the garage. Barry's mill is squeaky-clean! I'm still scraping grime on mine. =)

[damae]

After destroying my final good 1/2" endmill, I realized how much I needed a cooling system.

And so I proceeded to hiijack my wife's watering can and tried pouring the coolant into the path of the cutter manually. Not only was my arm tired, but it was an extremely messy process trying to fill up the can and resume pouring before the cutter made the next pass!

Hearing of my troubles, my neighbor had some pity on me and loaned me his tiny water fountain pump. It managed to get fluid about 18" up the pipe, but could not muster enough head to get it up to the table! That's when I finally gave in and ordered a 10 gallon system from Enco for about $130. And boy am I glad I did!

The metal tank is nothing special -- just welded sheetmetal. But the pump is quiet and powerful. In fact, it can pump about twice as fast as my table drain can return the fluid back down to the coolant tank! Fluid was again splashing everywhere because of the powerful stream. Fortunately, I realized I can control the flow by partially closing the supplied ball valve.

then it was on to rigging a better spray shield. By better, I mean better than a bunch of cardboard clipped to the table, which is what I had for my earlier coolant experiments. Haha! First, I have a polycarbonate vise-mounted shield made by Kurt. Next, I started to make use of bits of aluminum I bought at the scrapyard "because someday I'll need it." Tin snips made short work of the thinnest pieces and I placed them in between the Kurt shield and my rear splashguard. The rear splashgaurd was originally an aluminum keyboard shelf, but it fits perfectly on my table, almost like it belongs there!

I already made some cuts with coolant and it really does make a huge difference! I'm pleased as punch... or is that blue kool-mist?

[damae]

Hey, some pictures! (more pictures)

This time showing a fixture I'm cutting into some soft jaws that will be mounted in the Kurt vise. The process worked beautifully, cutting .050" deep at 40 IPM and 3000 RPM, probably still very conservative. The finish was great and everything went as I hoped. Oh, except for being out of tolerance by 0.020"!!!!

Yeah, I found a 1/2" EM in a pile of old tooling and thought "great, I don't have to wait for my new cutters to arrive," but I didn't realize it had a "history." Some time in this cutter's past, it had been resharpened, and in the process made into a 0.490" EM instead of a 1/2" EM as marked on the shank. So now I'm dead in the water until my new cutters arrive.

Oh well -- I'm still pleased as Kool-Mist that the coolant works so well!

[Barry_ward]

Hey Damae,

I love seeing you use coolant. I need it, but have been afraid of the mess management. You are forcing me to forge ahead. What coolant are you using????

Thanks for the praise on my retro but it is really far from being done. I want to try to get the front panel in place soon so that there is a real Estop button (instead of the keyboard or mouse estops) I also need to mount the buttons for my drawbar as the switch is dangling by the wires...

Washing Machine: I was forced to use the pressure washer due to the mass of clay-grease like crud on the machine. Even after PW, it took weeks of scraping, washing, dis-assembling, scotch-brighting and lube spraying to get it clean enough to touch with my "day job" clothes on. Attached image are brackets that still need to go on the machine - 1/8" crud missed by PW.

As far as the Estop goes, I think that I will add a contactor between the power supply and the motors so that the DC is instantly shut off to stop the motors without waiting for the big cap to discharge. On Kens big machine Fanuc has a contactor for each motor. When engaged everything is normal; when disengaged, the contactor shorts the motor out. This has the effect of stopping it instantly and acting as a power-off-parking-brake.

One other question? do you use a keyless chuck? I have a new (gifted to me) Albrecht which I used for some various CNC drilling (3/8 & #29) on some of my aluminum extrusions. Maybe I just don't know how to get it tight, but it has slipped more than once. Some guys swear by them - At this point I swear at it. If I don't get help, it's going to get religated to the basement drillpress.....

best regards,

B

[Kevin Taylor]

Amae Look's like your on the right track with the coolant take a look at my encloser on the BTC clubhouse the base is the origonal BPT and the rest is almost done. might be to big for your space your part look's like a soft jaw for a kurt vice ? Can you overcome the size with cuttercomp or rewright the tool path +.005" offset? I have yet to master CC even though my machine is capable but offten just regenerate the tool path when faced with the wrong size tool Keep up the good work Kevin

[Adobe Machine]

I buy "resharpned" carbide cutters by the dozen from a very good grind shop in Tucson. Cost is $4-$5 each, and he does an outstanding job on the resharpen. I mark each cutter with the actual measurment, then put it in the the tool log in my Vector CAD/ CAM program ( I also number them) and Desk CNC. The measurements are comped in the tool path..This is ok where only one person is using the equipment, but in a High Tolerance shop it may be dangerous..You know, make 4000 widgets( sorry Eric )and be off 0.010 could be more expensive than the money saved.

I actually took a day and went to some CNC shops and bought their so called "scraped" carbide cutters..I came home with 140 good canidates for resharpen for less than $40 bucks and some diesel fuel..I found a lot of good end mills that had been tossed for no reason, the rest I had sharpned.

Found a bunch of little plastic containers that we used for each carbide end mill to keep them apart and organised. I figured my cost per carbide end-mill
( most are 1/2", some 3/4", and very few 1//4"and 3/8") is about $7.00 each,
a lot less than even Enco..

Adobe (old as dirt)

[unterhaus]

One other question? do you use a keyless chuck? I have a new (gifted to me) Albrecht which I used for some various CNC drilling (3/8 & #29) on some of my aluminum extrusions. Maybe I just don't know how to get it tight, but it has slipped more than once. Some guys swear by them - At this point I swear at it. If I don't get help, it's going to get religated to the basement drillpress.....

best regards,

B

I think for heavy cuts you are better off with a keyed chuck. I don't think they really work at 3/8-1/2". I've used them for edge finding and center drilling, and some small drills.

[damae]

...I love seeing you use coolant. I need it, but have been afraid of the mess management. You are forcing me to forge ahead. What coolant are you using????

Barry, glad to 'twist your arm' into using coolant! =) I use Kool-Mist, mixed very rich, about 5:1 because I absolutely want to avoid rust problems. No particular reason for picking this brand, except that my local supplier (Tool Supply Inc.) has this on hand.

Thanks for the praise on my retro but it is really far from being done. I want to try to get the front panel in place soon so that there is a real Estop button (instead of the keyboard or mouse estops) I also need to mount the buttons for my drawbar as the switch is dangling by the wires...

Same here! I want to mount at least one E-Stop close to the front of the machine. It's especially troublesome to have to open the control box enclosure just to turn the spindle on or off!

Washing Machine: I was forced to use the pressure washer due to the mass of clay-grease like crud on the machine. Even after PW, it took weeks of scraping, washing, dis-assembling, scotch-brighting and lube spraying to get it clean enough to touch with my "day job" clothes on...

I suppose there's no true shortcut to cleaning up a decade or more of grime! Except to hire a high school student to do it for you! Haha!

One other question? do you use a keyless chuck? ...Maybe I just don't know how to get it tight, but it has slipped more than once. ...

Well, I doubt you're doing something wrong -- keyless chucks should reach full tightness by hand. I was just bidding on a drill chuck for my machine, and was wondering the same thing. Based on what you say, I'm going to get a keyed chuck instead of keyless, just to be safe.

[damae]

... take a look at my encloser on the BTC clubhouse the base is the origonal BPT and the rest is almost done....

Kevin, that's a really nice setup you have there! I do need to figure out something more permanent, but I was thinking to keep it contained inside the dimensions of the table.

...look's like a soft jaw for a kurt vice ? Can you overcome the size with cuttercomp or rewright the tool path +.005" offset? ...

Yes, it is an aluminum soft jaw I was cutting on. You are also right about adjusting toolpaths and cutter diameters in software... so I guess I don't really have an excuse to hide behind, do I? =) It's a bit of a pain to regen the toolpaths, because I am still very clumsy with BobCAM and transfering the file is a little awkward. I have to put it on a USB stick, carry it downstairs, open the control cabinet, unplug the USB keyboard and insert the USB memory stick, copy the file (using mouse only) and then swap the keyboard back in.

I sorely need a USB hub and a panel-mount USB port!

[damae]

I buy "resharpned" carbide cutters by the dozen from a very good grind shop in Tucson. Cost is $4-$5 each, and he does an outstanding job on the resharpen...

Not a bad idea! I already have my own pile of wasted tooling. Perhaps they can be shortened and reground.

I actually took a day and went to some CNC shops and bought their so called "scraped" carbide cutters..I came home with 140 good canidates for resharpen for less than $40 bucks and some diesel fuel..I found a lot of good end mills that had been tossed for no reason, the rest I had sharpned.... I figured my cost per carbide end-mill ... is about $7.00 each, a lot less than even Enco..

Thanks for the hot tip! Do you trust your calipers to produce an accurate measured diameter, or do you make a hole with the cutter and then check the hole with gage pins to account for uneven or off-center grinding? Or is that not a problem at all?

[Barry_ward]

D,

From what I understand, you want to mix the coolant with the proper concentration. They even sell refractometers to ensure the concentartion is correct.

from http://www.coolantmaintenance.com/
Too low a concentration can dull tools prematurely, or even break them during the first cut. Too high a concentration not only causes higher usage rates, but can also lead to health and safety issues.

B

[damae]

D,
From what I understand, you want to mix the coolant with the proper concentration...

Hey, nice new avatar, Barry! Shizuoka Red!

You bring up a good point about health issues with high concentrations. I just really, really hate rust. I guess that comes from growing up in Hawaii, where every car over 5 years old has rust! In fact, I never did own a car there that didn't have visible body rust; one even had rust so bad you could stand in the hatch area with your feet thru the car, like Fred Flintstone!

Anyway, who likes rust? Of course, I am only assuming higher concentrations of coolant mean less corrosion.

You're right, I really do need to see what concentration is appropriate. Kool Mist 77 is 100% synthetic and intended to be mixed pretty thin -- 32:1! This particular brand is meant to be used as either mist or flood coolant. I wonder if I can get away with higher concentrations when using it in a flood-only application.

I also bought a large box of latex gloves to use around the coolant.

[Adobe Machine]

Re: reground tooling. I cut a slot in some scrap alum, then measure using my guage block set..quick and easy for tolerances of .001 to.002, if I have to mill to tenths, use a new , carbide endmill, but have gotten in the habit of checking those the same way.I have some new, never used 1/2 " end mills that are 3-4 years old..due to using the regrinds.At least there might be something new when my wife auctions everything..

Adobe (old as dirt)

[Barry_ward]

D,

Have you had a rust problem due to coolant?



My machine is in the garage and the physics are bad.

The temperature in the garage can get into the 40s fairly easily. Then in the day the outside temperature goes way up. If it rains and someone opens the garage, the machine sweats (a lot)

Every surface of the machine has a light coat of LPS II which seems to offer enough protection. (LPS is by far the best spray lube I've found, and the II is a good general viscosity) (It's also a good cleaner of thick stuck on greasy-grime)

Sometimes I'll run a heater on the machine just to cut down on the condensation. As long as it's a couple of degF hotter the moisture is driven elsewhere.

B