[MechanoMan]

I'm wondering what I can do to prevent chips from getting onto that poor unprotected bottom part of the Z-leadscrew.

I've seen a pic where there was a rubber curtain similar to the way/motor covers on the X/Y. Is that a stock item somewhere? Are there other ways of solving this problem? The downside I see is bunching up, when the Z is low and the Y near the column then the curtain may bunch up and buckle over into the work area, at least I think it might.

[DonFrambach]

Here is one guy's solution:

http://nyccnc.com/Herbie/HERBIES_BLO...__bellows.html

[doanwannapickle]

I have exactly what you describe on my mill. It's been there so long I thought it was stock. I just attached it with a hot glue gun and it's been trouble free for years. I've never noticed an interference problem.

Cheers,
Walt

[MechanoMan]

Well that's... exactly what I'm looking for.

That's no fun. Doesn't anyone have a solution which starts with a common household item, appears simple and dirt cheap at first, then requires 6 months of tweaking and $100 in additional parts/tools to get it to work?

Because that's just the way I'm used to working.

[CROSSHATCH]

I have the best solution. It's done on my Taig.

Go to Home Depot. Bath section, get bath liner cut and rig it to your z and x. Been using it for months!

[japroach]

I have exactly what you describe on my mill. It's been there so long I thought it was stock. I just attached it with a hot glue gun and it's been trouble free for years. I've never noticed an interference problem.

Cheers,
Walt

I like the dual motor setup, what are their specs?

[doanwannapickle]

I like the dual motor setup, what are their specs?

Couldn't say. Those are brushed DC servos and the way they spec'd them made no sense to me. They deliver 7000 rpm at the cutter and have plenty of power.

There's a high and low range but I seldom need to us the low range.

I never cared much for the cantilevered setup with the OEM motor.

Here's a little better shot.

[fretsman]

Couldn't say. Those are brushed DC servos and the way they spec'd them made no sense to me. They deliver 7000 rpm at the cutter and have plenty of power.

There's a high and low range but I seldom need to us the low range.

I never cared much for the cantilevered setup with the OEM motor.

Here's a little better shot.

I see you have a ballscrew in your z axis, and do you have these in the other axis, and may I ask what type of anti-backlash setup you have?

Thanks,
Dave

[doanwannapickle]

All three ball screws are of the single nut type. The z axis is just a cheap rolled screw and relies on gravity for it's anti-backlash.

The x and y screws are much better quality - I'm attaching a couple of pictures of what they looked like before modifying them to squeeze into the Taig. This type of screw relies on their high precision and a rolling press fit between the nut and screw.

[fretsman]

Interesting, may I ask what brand/info these are? I thought they all had some sort of backlash, I still learn something new everyday-

Sorry for the Off topic chatter mechanoman-

Dave

[doanwannapickle]

Any press fit has negative clearance which provides very accurate location. This is the principle behind a dowel pin. A rolling element is able to have a press fit and still move freely and smoothly. This is the principle behind ball lead screws. If there is enough room and budget, the preferred method is to use two nuts that oppose each other to provide the press. The same as is done with the OEM Taig screw. That gives some ability to adjust. When my screw wears out, it's dead.

[fretsman]

I completely understand the theory of a rolling fit but I thought maybe yours were something different, now you've made it very clear what you have, thanks for that.

I'd love to add ball screws at some point, but as you know, it will be a "project" for sure-

Dave

[5artist5]

Yeah, what we need is for one of you geniuses to start selling a ball screw conversion kit for the Taig. You know there is a bunch of money in it as I am sure that practically every person on this board would buy one.

[doanwannapickle]

Well, I hope MechanoMan has decided how he's going to protect his lead screw since we've totally hijacked his thread.

As far a ball screws go, I'm the only one I know of that has actually done it and I usually discourage others from trying it. The Taig comes with really good screws even it they are a bit slow.

There are a lot of other modifications that I feel have a lot more bang for the buck. I think I'll start a thread on that when I get a bit more time.

Cheers,
Walt

[MechanoMan]

I'm fine, jack away.

What was the problem with the ballscrew? Or was it just not worth it?

What do people mean when they call the Taig leadscrew "slow"? I didn't see a practical limit until like 60-80ipm, and that's beyond what I could work most of my materials at except wood.

[rowbare]

I'm fine, jack away.

What was the problem with the ballscrew? Or was it just not worth it?

What do people mean when they call the Taig leadscrew "slow"? I didn't see a practical limit until like 60-80ipm, and that's beyond what I could work most of my materials at except wood.

It mostly has to do with the torque curve of a stepper motor. The torque drops off drastically as the speed increases so it gets more and more difficult to do useful work as the speed increases.

At 80 ipm your steppers are turning 1600 rpm which is beyond where steppers do their best work.

[doanwannapickle]

I'm fine, jack away.

What was the problem with the ballscrew? Or was it just not worth it?

What do people mean when they call the Taig leadscrew "slow"? I didn't see a practical limit until like 60-80ipm, and that's beyond what I could work most of my materials at except wood.

There's no 'problem' with ballscrews, they work great. It's just that they are very difficult to squeeze into such a small machine and they are expensive. I feel that most people would not be able to justify the time and cost involved in getting them installed. Particularly when there are so many other mods with lower cost and quicker return. It's all about cost/benefit.

If they were designed in at the factory it might be doable but even they would need to contract with a ball screw manufacturer to produce a special. By then, you've doubled the cost of the machine. I would be surprised if they haven't given it some thought.

BTW, even with the ball screws I set my rapids to 60 ipm. It's just too quick to keep up with at higher rates.

[MechanoMan]

OK I got the z-axis bellow material in.
Found that LittleMachineShop also had brackets for that, which I wish I'd known about, although I probably wouldn't have been able to use.

I ended up taking a pair of steel strips wider than the headstock and 2 long 10-24 allthread rods to clamp the strips above and below the headstock with the bellow end clamped under the bottom strip. I can undo this thing at any time for cleaning or if the job requires moving the table so far it'll pinch the bellow against the screw.

I did not have to drill or glue anything to the headstock.

In retrospect I should have threaded the bottom bracket and used a wingnut+jamnut to make a finger-screw system. I kinda screwed up by drilling the holes in the bracket so close to the headstock width that there's no lateral room to put a nut above the lower bracket to lock the allthread onto it.

It doesn't "fold up" really well. When it drops it falls onto the Y-axis way cover and s-folds itself down into a pile one way or the other. It CAN pick up crud on the backside if it starts by falling backwards once it lays on the Y-axis cover. Then when it lifts it carries the crud onto the Z-axis screw. Still better than just letting crud spray onto the Z-screw every time.

[fretsman]

Here's how mine looks as I also used the little machine shop bellows. I completely removed the rear Y axis cover and just used one long one for both. It folds up pretty well when the Y is all the way back but will sometimes fall on the material which is fine. It's not like it's "in the way" or anything. Took a couple of times to get just the right length, but it's great for me.

Dave