[CFLBob]

I forgot one thing. Where can I get replacements or extras of the balls in the C7 ball nuts?

I think they're .124?

[hoss2006]

The best prices are at toolsupply on ebay.
Great deals from ToolSupply | eBay Stores
Hoss

[denvermatt]

Hey guys. I purchased Hoss's DVD and plans a couple weeks ago and am in the process of putting together my shopping list for components.

One question I have is about waterproofing the stepper motors for the flood coolant. I called Automation Technologies and asked about waterproofing the motors, but despite the fact that they list it as an option on their website, the guy said they don't do that type of thing for small orders of only 3 motors. They only do it for larger production runs.

My plan was to take Hoss's advice and get two Nema 23s and a Nema 34. But I'm just not sure what to do about the flood coolant and making sure I don't short anything out.

What do you guys do about this?

Thanks!

>Matt

[CFLBob]

Matt,


I don't want to step on anyone else's toes, but here's a For What It's Worth. Motors can't really be waterproofed from the outside once the motor is built. You can squirt some RTV around the where the wires exit the body, and that's about as good as it's going to get. Anything else has to be designed and built into the motor. And nobody in the business is going to tell you a motor is "waterproof". They're going to tell you it will be rated to a code like IP67 or to some other specification it can be tested to. (IP ratings are an industry standard way of specifying how tightly something is sealed against dust and moisture, among other things). You're probably thinking "so if I put RTV on the wires, what about where the spinning shaft comes out of the motor?" Motors have to be designed to meet these specifications, they can't be coated with something to fix them once they're built.

I used to design parts of commercial airborne weather radars. Weather radars use stepper motors (this radar used NEMA 23 for left/right and NEMA 17 for up/down). Weather radars are in the nose of the aircraft outside the pressurized vessel and it's a hostile environment. One minute they're flying along at altitude where the air temperature is way below zero (think -40 or -50) and a few minutes later they descend into warmer, wetter air. When that air hits the cold metal of the radar, the humidity condenses into streams of water and the water flows like crazy until the radar warms up (which is after it has done its job).

We had our share of motor issues over the years. One of my last tasks was to evaluate motors from a company that guaranteed they'd survive a milspec salt water spray test: a week with hot salt water sprayed on them. Which they did as claimed. Non-treated motors would generally turn into large piles of corrosion. The metal in the good motors was specially treated and the most important part is that to get the required torque out of the motor, the gap between the rotating parts on the shaft and the stationary parts had to be precisely designed and waterproofed in a proprietary way.

So unless the motor is specifically designed, squirt some RTV around where the wires leave the body, and protect it from coolant being sprayed on it, and you'll get about as good as it can be.


Bob

[hoss2006]

Hey guys. I purchased Hoss's DVD and plans a couple weeks ago and am in the process of putting together my shopping list for components.

One question I have is about waterproofing the stepper motors for the flood coolant. I called Automation Technologies and asked about waterproofing the motors, but despite the fact that they list it as an option on their website, the guy said they don't do that type of thing for small orders of only 3 motors. They only do it for larger production runs.

My plan was to take Hoss's advice and get two Nema 23s and a Nema 34. But I'm just not sure what to do about the flood coolant and making sure I don't short anything out.

What do you guys do about this?

Thanks!

>Matt

The motors won't be immersed but will get splashed a bit.
A couple things I did was to make stepper end covers to protect the wiring a bit and plastic motor covers to deflect some of the splashing.
Hoss

https://www.youtube.com/watch?v=33sahEkLtPc

https://www.youtube.com/watch?v=OEfDVgEVvb8

[CFLBob]

Feeling better now. Did you get your ballnut mounted? I did the rear mount Y on mine, was thinking for a front mount an install tool might work better without the flange on it just basically a tube.
Hoss

Re-watching the video for the Y axis installation, I'm going to have the machined side of ball screw sticking out the front of the base, instead of the back. The ballnut, though has to have the same orientation as yours - the ballnut mount I made and the flange are toward the rear and the long tubular part of the ball nut points toward the front of the mill. That means the ball screw's non-machined end has to screw into the nut without the machined end to guide it and push the tool out toward the back.

Did you ever try to re-ball a ball nut using your tool instead of a screw? It seems like I could save a step and some hassle if I just got the balls into the nut without using the screw. The tool would just kind of hold the balls in place in the nut's threads. Otherwise, I have to put the balls into the nut on the screw, use the tool to take the nut/mount combination off the screw, then put it back on the non-machined end.

[denvermatt]

The motors won't be immersed but will get splashed a bit.
A couple things I did was to make stepper end covers to protect the wiring a bit and plastic motor covers to deflect some of the splashing.
Hoss

Thanks for the feedback Bob and Hoss. Not sure how I missed those two videos from Hoss, I thought I'd watched them all.

[Upnorth4]

Maybe not the right place for this post but I would like some feed back on an idea/adaptation of the MAD/ manual power draw bar.....
I would like to mill a shaft and pulley assembly for the belt drive conversion and figured why not put the belleville washer under a cap threaded onto a boss machined directly into the top of the pulley.... Essentially extend the shaft through the pulley, thread the OD and screw a cap over it... this way there would be no need to flip up the bar like in the version2 MAD.

Main concern is that the pressure to compress the bellevilles would be applied to the pulley/shaft/bearing, lifting on the bearing..... I'm very certain that the bearings can handle the load but will they be lifted out of the head? I'm thinking that a modified motor mount with a small flange over part of the bearing could keep it captive...

Does this make sense?

I love the idea of the MAD. I'm not looking into production work so the time savings of an ACT isn't an issue. For the massive cost savings I'll lift the quill instead of pushing a button, plus no pneumatics means no compressor to listen to.


In short is the force required to compress the bellville washers enough to lift the bearing out of the head and is so is it reasonable to contain the bearing with a plate?

[Fastest1]

Maybe not the right place for this post but I would like some feed back on an idea/adaptation of the MAD/ manual power draw bar.....
I would like to mill a shaft and pulley assembly for the belt drive conversion and figured why not put the belleville washer under a cap threaded onto a boss machined directly into the top of the pulley.... Essentially extend the shaft through the pulley, thread the OD and screw a cap over it... this way there would be no need to flip up the bar like in the version2 MAD.

Main concern is that the pressure to compress the bellevilles would be applied to the pulley/shaft/bearing, lifting on the bearing..... I'm very certain that the bearings can handle the load but will they be lifted out of the head? I'm thinking that a modified motor mount with a small flange over part of the bearing could keep it captive...

Does this make sense?

I love the idea of the MAD. I'm not looking into production work so the time savings of an ACT isn't an issue. For the massive cost savings I'll lift the quill instead of pushing a button, plus no pneumatics means no compressor to listen to.


In short is the force required to compress the bellville washers enough to lift the bearing out of the head and is so is it reasonable to contain the bearing with a plate?

To get repeatable tool lengths the quill needs to retract all the way up and rest against the spindle.
To release the TTS collet the quill also needs a little over travel. Your way would work if you used a shim between the quill and the spindle, remove the shim, press upward, change tool and reinstall the shim.
You could also thread for a bolt at the top in your cap. Stop the spindle, screw the bolt down a few turns by hand then lift the quill into it, change the tool. Unscrew the bolt a little and be on your way.


Sent from my iPhone using Tapatalk Pro

[Upnorth4]

With the cap spinning with the pulley, quill and spindle, the quill could rest against it. I'm guessing what you listed are the reasons Hoss has the version 2 MAD block fold down and out of the way. Agreed the quill has to retract fully to get repeatable tool lengths. I have found a quick and easy way to set the tool lengths is to use the quill, run it down until the tool touches a reference surface and lock in place.
Sometimes not the best practice, set tool lengths are faster.
I work with a machinist that has used a 2axis CNC Bridgeport. The Z was manually controlled with the micro adjust. This sort of flexibility appeals to me.

To get repeatable tool lengths the quill needs to retract all the way up and rest against the spindle.
To release the TTS collet the quill also needs a little over travel. Your way would work if you used a shim between the quill and the spindle, remove the shim, press upward, change tool and reinstall the shim.
You could also thread for a bolt at the top in your cap. Stop the spindle, screw the bolt down a few turns by hand then lift the quill into it, change the tool. Unscrew the bolt a little and be on your way.


Sent from my iPhone using Tapatalk Pro

[CFLBob]

Getting back to the other topic that's here lately, I tried to repack the balls into my Y axis nut and it didn't go well. The ballscrew seemed to push balls out of place.

The video posted (Repacking Ball Nut RM-16 C7 Ball Screw by ArizonaVideo99) talks about avoiding some races and says if you don't avoid those, the screw will bind but I could never see what he meant. It was only when I wore optivisors and put the the balls in at the crossover, then kept pushing them all the way around the race that I thought I got it right.

I put both of the wipers back in place, then put in my hardwood transfer tool (sort of like a ballnut removal tool, only simpler, more like the cardboard tube from 109jb). Then I was able to put the ballnut back on the screw with the screw in the base of the mill. Only it doesn't come forward enough. It has been so long since I started down this road, I forgot I might have to cut out part of the base.

I guess.

[hoss2006]

Yeah material still needs to be removed from the base just like shown for phase 2.
Hoss

[CFLBob]

Yeah material still needs to be removed from the base just like shown for phase 2.
Hoss

Just to double check, I'm the guy (the only one?) doing a front mounted motor. I thought the cutouts were for the shape of the phase 2 ballnut mount.

Let me tell you what it does: I let the ballscrew float a bit more before tightening the setscrews, and the nut wants to be a little below flush with the top of the cutout in the slide. The slide will pull forward where the front edge is 3/4" past the end of the base and over the spacer. The back edge of the slide stops about a 3/8" short of the back column. This is without the bearings and motor mounted, just with the ballnut at the end of the screw.

[hoss2006]

Pics would help but the back sounds about right, the front may go more.
The material removal in the base is strictly for ballnut clearance, flip it over and note where the ballnut is making contact with the base preventing it from moving forward more.
Hoss

[CFLBob]

It's hitting on the cutout. I pulled the gib strip looser and find I can pull the ballscrew forward until the leading edge of the cross slide is 1 1/4" past the end of the base.

I'm right at 6 1/2" of travel.

It seems like a casting bump (hard to call it flash) is stopping the rearward travel, and the forward end is that 1 1/4" you say to cut away.

If I cut out that 1.25", does the new hardware support 7 3/4" travel? It might be 8" by the time I smooth out the back wall.

[hoss2006]

You should be able to up to 9 inches travels with the material removed to allow it and the longer y ballscrews in the prints.
The cutouts are for both the front and rear mount steppers.
Hoss

[CFLBob]

I cutout the 1.25 x 1.25 section in that photo you posted and it sure doesn't seem to allow the double ballnut to move that much farther forward. I cut out 1-1/4 and picked up much less than that, judging by eyeballing the position of the nut and mount. I'd guess I picked up no more than 3/8. I was able to break some crud off the back of the casting, but haven't checked to see if I can get any closer to the column.

Right now I have a bigger problem. I'm trying to pull the Z-column, and two of those four big SHCS are killing me. The top two. I've used every tool in my tool box to try and budge them, even standing on my 10mm allen wrench (I'm about 215, so that should be at least 100 ft lbs of torque). I have a 10mm hex that fits my socket set and can't budge it. I've hammered on my allen wrench. I have a 90 PSI ratchet and that does nothing but bleed air. The only tool I haven't tried is my half inch breaker bar, because the socket is 3/8" drive and I don't have an adapter that goes 1/2 down to 3/8.

What's left? I'd rather not go buy another tool I'll hardly ever use, but a big impact wrench?

The one video I watched, the guy took it off with a freaking plastic Tee handle wrench. Obviously extremely different than mine. I think mine needs dynamite.

[Titaniumboy]

Is an impact ratchet different than an impact wrench? I found out that my cordless Dewalt impact driver was no match for a stuck bolt I had on a drill press vise. My BIL's air impact wrench unstuck that bolt almost instantaneously. I have to get one of those someday.

Or you could hit the stuck bolt with heat from a Benzomatic torch.

[CFLBob]

Is an impact ratchet different than an impact wrench? I found out that my cordless Dewalt impact driver was no match for a stuck bolt I had on a drill press vise. My BIL's air impact wrench unstuck that bolt almost instantaneously. I have to get one of those someday.

Or you could hit the stuck bolt with heat from a Benzomatic torch.

I like that idea. I can get a torch pretty easily, and it seems like it's fairly easy to try that and if it doesn't work try other stuff.

I have a corded, 1-1/4 HP DeWalt impact drill that has variable speed and reversing. I'd need a 10mm hex bit to put in it, but that has got to be cheaper than an air impact wrench.

The air ratchet I have is from a Craftsman accessory kit that came with a compressor I bought years ago. It's not an impact wrench and isn't marked with its torque, it just says not to exceed 90 PSI. From a look at cheap to mid-range air ratchets, it's probably less than 50 foot pounds. Physically, it looks like this, but I have no idea what it's rated to do.
Sears.com

[109jb]

Just slip a piece of pipe over the Allen wrench.