[mike_mccue]

I was a bit surprised when I realized the MaxNC isn't supplied with a collet wrench... but then I found a G-code file WRENCH.T in the included sample files and thought it might be a hint.

I had some scrap aluminum and used 8" of 2" wide x 1/8" thick flat stock.

Here's what I made last night:





I have to say... it was really fun to watch the machine work so smoothly. It cuts aluminum really well.

I can see that I need to develop some skill in clamping down the material. It wasn't a problem until the final pass started to release the part. I would pause the machine occasionally and then tape down any loose material. That seemed to help but in hind sight it seems like better clamping is the best way to go.

Does anyone have any thoughts about how they figure out the best way to clamp in a certain situation?

thanks,
mike

[escott76]

I was a bit surprised when I realized the MaxNC isn't supplied with a collet wrench... but then I found a G-code file WRENCH.T in the included sample files and thought it might be a hint.

I had some scrap aluminum and used 8" of 2" wide x 1/8" thick flat stock.

Here's what I made last night:





I have to say... it was really fun to watch the machine work so smoothly. It cuts aluminum really well.

I can see that I need to develop some skill in clamping down the material. It wasn't a problem until the final pass started to release the part. I would pause the machine occasionally and then tape down any loose material. That seemed to help but in hind sight it seems like better clamping is the best way to go.

Does anyone have any thoughts about how they figure out the best way to clamp in a certain situation?

thanks,
mike

Flat stock can often be double stick taped to a sacrificial plate, and then popped off. You just have to be careful not to wreck things when prying them up.
The other method for thicker parts is to use stock thicker than you need, cut out the profile, then flip the part, grab it in a vise, and fly cut the back down to the required thickness.
Workholding is an art in itself, there are many many different techniques. Just remember, if a setup looks unsafe, it probably is. Take the time to do it right, and keep all your fingers, toes, and eyes

[Fixittt]

another option I did when I cut the wrench is drilled some holes in the body of the wrench and use a couple of T nuts and a short bolts in the center to hold the wrench in place and toe nail clamps on the materials edge that will get cut away.

This works in certain situations but not all, you need to know your final outcome of the part which is where knowing g-code, gcode simulators ect come in.

But you did good and I am impressed, I leave for a week and a half and you cutting things already! Good job! all you needed was a kick in the butt!

[mike_mccue]

Thanks for the kick Fixxit. It was really helpful.

I hope you had a wonderful wedding and a nice trip to Florida.

I started programming in G-code in a text editor last week and I'm making progress with that. I sat at the computer for a day hoping something would happen before I realized I just need to knuckle down with paper and a Calculator and think the moves thru. I wrote up and made a sample of an electrical panel that I can use for my sound production work and I have some stock on order for a final run.

I am also just starting to comprehend how important it is to think about work holding and how you use it to relate to zero (obvious stuff of course... but only to the initiated) especially if you need to remount the work piece for more than one orientation.

I had some quick success and then sort of rode a roller coaster thru yesterday. My computer is a rebuild from my office stuff... and the hard drive started failing last week (I suspect form too long a period of dry storage) so I took the opportunity to install FreeDOS and then a fresh XP install for a dual boot system.

Last night I got the machine running again.

MAX for DOS runs great. (and MAXWIN was working as well) I received and installed MAXIII last week and am just staring to learn it.

I'm about to switch over to the MACHIII registration.

I have a lot to learn about MAXIII/MACH 3 because last night I sent to the Z axis UP by accident and nearly ripped the stop switch of it's mount.

The little aluminum bracket is bent... but I can still zero.

I know it was my fault to have pressed a button without enough fore thought.... but I sorta hoped the MAXIII package had come with correct limits... MAX for DOS was setup to protect me from this.

So, that's where I'm at... I have to learn soft limits for MACH before I do much more.

Thanks again.

best regards,
mike

[BrianT]

Hi Mike,
I have a maxNC-10 and I am having great difficulty finding correct settings for milling aluminium.

What was your cutter type, cutter diameter, feed rate, depth per pass, RPM, etc for the collet wrench.

Cheers
BrianT

[mike_mccue]

Hi Brian,

I ran a 1/8" carbide two flute end mill at 0.06" depth. 2.0 feed rate and 6000 rpm on the motor.

best,
mike

[SCzEngrgGroup]

Hi Brian,

I ran a 1/8" carbide two flute end mill at 0.06" depth. 2.0 feed rate and 6000 rpm on the motor.

best,
mike

That is WAAAAAAY too slow to be feeding that thing - you'll wear the cutters out very quickly like that, and generate a lot of unnecessary heat. At 6K RPM with a carbide tool, and such a shallow cut, you should be able to run at least 15-20 IPM. I run my 1/8" HSS tools at 0.125" DOC, 12 IPM at 8200 RPM. Carbide tools should be able to do close to twice that, if they don't break off first.

Regards,
Ray L.

[mike_mccue]

Are you running a little mill like a Max 10CL-B?

best,
mike

[SCzEngrgGroup]

Are you running a little mill like a Max 10CL-B?

best,
mike

No, I run a knee mill. But with such a small cutter, the size of the machine is largely irrelevent, as the forces involved are quite small. The fact remains, running with a very low chipload is murder on the tool - it spends most of its time rubbing the work, rather than cutting it. You're only running a chipload of roughly 0.00015" - you should be about 3-5X that with an 1/8" tool.

I will somewhat modify what I said earlier - since you are presumably RPM limited at 6000, your feed should really be about 8 IPM, and using carbide does not help you at all, since you're not even running a proper SFPM for HSS.

Regards,
Ray L.

[mike_mccue]

Yes,
I think the MaxNC CL-B introduces some compromises. I can afford a bunch of $10 carbide bits. :-)

The MaxNC was a gift. I'm interested in not blowing it apart by overtaxing the fittings.

I plan to increase feed rate in an effort to use the cutter to best advantage.

I have a 10,000 rpm motor but belt and pulleys function as a reducer so I think I'm only running half speed at the spindle. To date I've run the motor at 6000rpm so I assume the spindle is at apprx half that.

Thank you for the good advice.

best regards,
mike

[SCzEngrgGroup]

Yes,
I think the MaxNC CL-B introduces some compromises. I can afford a bunch of $10 carbide bits. :-)

The MaxNC was a gift. I'm interested in not blowing it apart by overtaxing the fittings.

I plan to increase feed rate in an effort to use the cutter to best advantage.

I have a 10,000 rpm motor but belt and pulleys function as a reducer so I think I'm only running half speed at the spindle. To date I've run the motor at 6000rpm so I assume the spindle is at apprx half that.

Thank you for the good advice.

best regards,
mike

Well if the motor speed is not the spindle speed, then it's pointless to tell us what the motor speed is - it doesn't matter, only spindle speed does. so, if you're running 3000RPM at the spindle, then you're only off by perhaps a factor of 2 in feedrate.

Regards,
Ray L.

[blim]

Just got an old MAXNC 10 which I am converting to GRBL now. There was only one collet for the spindle with the machine, and I can not figure out what type of collet that is. Size is 11mm, but it did not work with an ER11 collet I had laying around. Seems like it should be a wider angle on the collet for it to fit well. Anyone know what collet type it should use?

[DICKEYBIRD]

The MaxNC website says ER-16.

[blim]

Think that applies to newer machines. I measured the hole in the tightening nut, and it is 11 mm. The tip of the collet is also 11, but it has another geometry than ER- collets.

[awerby]

The older MaxNC machines used proprietary collets made by Taig Tools. It's not an ER system, where the collets snap into the closer nut, but a simpler one that's non-standard. Taig still has them; see if these look familiar: Taig Tools - Desktop Milling Machines and Lathes.

[blim]

Thanks,
Ok so they are outdated, and no metric collets. Think I'll buy an ER16 shank and rebuild the spindle.

More: The motor is missing from the machine I got. Whats your opinion: Buy a separate motor and stick to belt transmission, or buy one of the ebay spindles with motor on the spindle. Like this one: DC12 48V CNC 300W Spindle Motor with Mount Bracket for Engraving Carving | eBay.

Guess the last alternative is less rigid compared to the original spindle, though.

[awerby]

I suppose you could try to build your own ER spindle. But then you're faced with rebuilding the rest of that machine - putting in bearings to support the screws would be the first order of business, and then you could figure out how to support the motors properly. As for that Chinese spindle, it would work for cutting wood, if that's what you want to do. But it won't go slow enough for metals, with the possible exception of aluminum. The original MaxNCs like yours used Dayton universal motors that spun fast but tended to burn up.

[blim]

Thanks,
What kind of belt system and pulleys should I use between motor and spindle. Will use a motor with speed control, so no need to change gear ratio. I have some GT2 timing belt and pulleys. would it be okay to use that?

[awerby]

The original system used a 10k rpm motor. But it was not really suitable for this application and failed regularly, as I mentioned. But if you plan to cut wood with this thing, then getting 10k rpm out of the spindle is desirable. So you need to take the max motor RPM into account and get pulleys that will give you that. Speed-controlled motors are convenient, but you don't get the torque multiplication in the low range that you get with a pulley system. I wouldn't use a timing belt for this, since the belt won't slip if something jams, and it will kill your motor.

[blim]

Those are good reflections and advises. Thanks
And if I some time decide to upgrade the lead screws. Do you have any suggestion for a proper type, size and pitch for a screw? Not sure of what pitch is on the screws on the machine currently, but I guess the seek rate will be low. The steppers I use will have plenty of torque, so I could get a higher pitch screw for more speed. But not sure if I need that.. Any thoughts?