Seig X1 CNC Conversion Help

[GraflexGuy]

Hello,

Yes, another Seig mill conversion thread... However I haven't seen much discussion on the X1 within quite a few years span, and those threads never seemed to come to any resolution. To make matters worse, all of the referenced material (Hossmachine, CNCfusion, Yahoo groups) are dead.

I've basically been given a Seig X1 (HF Model), with a shredded transmission. Since I already have a nice manual mill, i'm planning on converting this to belt drive and making it a CNC. I've done some RC and 3d printing projects in the past, but I have no idea where to start with CNC beyond the basic concept of it.

I'd like to build something reasonably functional for the lowest initial cost, possibly upgrading as I learn, so i'll be skipping a ballscrew upgrade for now, and just dealing with backlash adjustments in software. I'm not sure the design of the belt drive yet. I haven't decided if it's really important to keep the weight of the motor centered directly over the head or not. I'm probably going to fabricate a plate and turn some pulleys but i'm not sure what size I need for the best speed using small tools taking repeated light cuts on aluminum and steel.

Anyway, to sum up, here's my planned build so far:
Base Mill: HF Seig X1 (I'm planning to counterweight the head + modifications)
Motors, Control Board, Drivers, PSU: https://www.amazon.com/gp/product/B09MRQKF43/ref=ox_sc_act_title_2?smid=A3E9T3KQ1YPBBY&th=1
Motor Mounting: https://www.thingiverse.com/thing:873408
Computer: One of my junk computers I have lying around
Software: Probably going to look into CNC Linux.
Belt Drive: I need help determining pulley size, but will fabricate as needed.

Does that electronics package seem sufficient? Am I missing something critical that's necessary to function? How do I determine a good pulley size?

 

[matthewsx]

Those should work. If it were me I'd do the ballscrews right away, they're fairly reasonable on ebay and you'll want them eventually. I used Linux CNC with my project and it's a great way to get started.

There are plenty of belt ratio calculators on the web, will you be using a variable speed motor?

I think we need some pictures of the machine in question though....

Having a working mill will make your project much easier than mine was.

John

 

[homebrewed]

I have just one suggestion/concern. Acme threads will require more torque to drive them compared to ballscrews. A pre-packaged motor-driver combination for a CNC application may assume lower-friction ballscrews. Before you buy, check out other build logs for the X1 to see what they did and what problems they encountered along the way.

I've used linux CNC, albeit in a limited fashion. It worked OK for my needs. It drove a Sherline mill. I never had to mess with the backlash parameters, but Sherline uses a two-nut scheme to reduce backlash. Despite this, standard screw+nut lead screw combinations will eventually wear and cause variations in backlash over the extent of the table motion. So you have to think about that in terms what your plans are for your X1 CNC setup.

 

[GraflexGuy]

Here's a link to the model of the mill in question: https://www.siegind.com/shop/x1-micro-mill-drill
Mine is identical, except for the fact that i've disassembled the top end above the spindle. Here's an exploded diagram: https://littlemachineshop.com/images/gallery/PartsDiagrams/X1_Micro_Mill_HarborFreight_47158.pdf
If that's not helpful enough let me know, and I can send some photos when I get a chance.

I'm planning on reusing the original DC motor and variable speed controller that came with the mill. It's supposed to be about 4000 rpm without reduction. From what i've seen, it seems like the faster the better with CNC? Do you just control the feeds and depths and not really worry about the speeds, or is this assuming active coolant?

Interesting point about the backlash becoming variable in different areas of the leadscrew... The machine as it stands now has almost no wear on it, what if I were to replace the leadscrew nut with a nylon or delrin or even PLA replacement part to concentrate the wear there instead? That should give consistent backlash over the entire travel, if a somewhat more accelerated wear rate, yes?

I'm going to eventually upgrade to ballscrews when the wear necessitates them, but not at first (mostly to get rolling on a budget with the fewest things needed). I will probably do those at the same time I put a bigger table on to really make it worthwhile. I checked several other build logs and it seems that people use nema 23 and 32s for both ball screw and non-ballscrew conversions, but in the instances where the original screws were kept, thrust bushings were usually used. Turning by hand, the head is the only axis that really feels like it has much resistance and I plan to counterweight that anyway so that should help.

Complete build logs for the X1 are harder to find it seems, what I've come across is partial or for the X2, so i'll keep posting here as I go to hopefully re-document some of the information. If those steppers can drive an X2, a little X1 should be fine, right?

As to use? Nothing super dimensionally critical i'd imagine. Adapter plates, maybe some engraving, Small models, parts for my other machines, etc. I'm not really sure yet. All the stock will be prepped in my larger manual mill most likely.

 

[matthewsx]

Nema 23 will be fine for your use. Ball screws are cheap on eBay and since you have a mill you could make all your mounting hardware to save $$. I've done the delrin nut thing and it's not as satisfying as you might think.

I suspect a lot of folks start down this path and don't finish, it sounds like you have reasonable expectations so that will help lots.

Here's my CNC project if you're interested....

Homemade vertical mill drill

Well, I guess I'm gonna try to make myself a mill for cheap. I found this column on Craigslist for $80. And I ordered this spindle I can power with a VFD I already have. And I'm going to get one of these cheap x-y milling tables. And probably look for a really flat piece of C channel...

www.hobby-machinist.com

John

 

[homebrewed]

Interesting point about the backlash becoming variable in different areas of the leadscrew... The machine as it stands now has almost no wear on it, what if I were to replace the leadscrew nut with a nylon or delrin or even PLA replacement part to concentrate the wear there instead? That should give consistent backlash over the entire travel, if a somewhat more accelerated wear rate, yes?

I don't think so. A softer-but-tougher piece like a plastic nut will actually wear more slowly than the lead screw. And, even if they wore at the same rate, it still depends on what portion of the LS is used most. It doesn't matter how much the nut wears in this regard. The nut doesn't exclusively determine the amount of backlash. They BOTH do.