[cowanrg]

I've been doing a little posting here and there on the forum, but the mill arrived, so it's time to officially start a build log. This is my 3rd mill that I've converted. My first was a round column and I learned a lot from that one. Basically, don't convert a round column. I didn't really listen and bought it because it was the best bang for the buck in terms of machine size and price. But it wasn't a great machine and the conversion wasn't really all that great.

This kinda stopped me from pursuing CNC and machining in general for several years. I caught the bug again and bought a cheap X2 clone from craigslist. I did a very basic conversion, knowing I'd get something bigger some day. I just laser cut all the mounts and kept the original ball screws. It works surprisingly well considering. But it's tiny, underpowered, and just not the right mill for me.

I ended up with a PM-30MV-L after a bit of debating. I just realized the G0704 was a great mill, but for a bit extra, the PM-30MV-L was bigger, more powerful, and better quality (in some aspects).

I put 'open source' in the title because I plan on sharing every aspect of my conversion, down to all the design files, which I will throw up on 3D content central, so people can convert them to their favorite platform, or just download the drawings. I come from an open-source background (work for a hardware/software company that's completely open source), and I like the idea of information being free to everyone and easily accessible.

I've started a blog to document my journey, and have updated the posts to where I'm at right now.

I got the mill last Wednesday and put some casters on the base, cleaned it up a bit, and hoisted the mill on the stand. Now the fun stuff begins!

I really hope people find the information useful. I've found a lot of great information here and I just want to share further.

Here are the posts on my blog so you can see the progress. Warning, I have a ton of photos (first the first couple of blog posts anyways):

CNC Conversion: Part 1 – Choosing the Right Milling Machine
CNC Conversion: Part 2 – The Mill Arrives
CNC Conversion: Part 3 – The Stand and Leveling Casters
CNC Conversion: Part 4 – Overcoming Gravity

Lastly, here's my 'roadmap' for what I plan to do. In short, I'm not doing anything special... 570 oz/in steppers, KL-5056D drivers, ball screws, etc. I may plan on doing a power draw bar down the road and some other stuff, but I'm gonna start with just getting the mill going first. Here's the full rundown on my blog:

CNC Conversion: Part 5 – Conversion Roadmap

[AVRnj]

Read through your blog, nice documentation of everything! At the rate you are going you are going to pass me up! Looking forward to following your build, hopefully we can share some ideas. You mention that the stand is better stationary than mobile, did you find that it lost rigidity once you put those casters on? I would have thought with the rubber at the bottom when the wheels were not engaged that it might actually provide better vibration dampening than the steel on it's own.

I am still debating what I plan to do for a stand. For now my plan is to do the X and Y on the provided stand, and decide before I put the Z axis back on the base. If I use the included base, I will either do casters like you did, or I may use hockey pucks as I really don't need the mobility, or don't plan to, although it would certainly be nice.

[cowanrg]

I think you have a pretty good head start on me actually! Getting the mill setup and on casters was pretty easy. There's along road ahead.

I never really used the stand by itself, so I can't really compare the two (with and without casters). However, I used to have a round column mill which was about the same weight and I remember the stand (it was pretty similar). It was stable, but needed quite a bit of shimming. Also, it rattled a lot because of the concrete to metal contact. The wheels allow the stand to move, but if I bought those feet for mobility only, I'd be unhappy. It moves, but it's a bit of a pain and they are always getting stuck on something, and don't swivel too easily. BUT, when you get the floor clean and line them up, it moves just fine and doesn't feel unstable at all.

For me, I just wanted the mobility because I don't want to go sliding it around my garage as I work on it. It's eventually going up against a wall, but for right now, I like it more out in the middle of the garage, where I can get behind it, and have access on the sides. So, it's nice having it mobile because I can work on it a lot better. In its final place, it might not move for months at a time.

I haven't fully 'leveled' it yet, just screwed the feet down until touching to see how it was. It's pretty darn stable. It's obviously not as stable as some of these guys with the welded tubular frames and such, but it's acceptable for what the machine will be doing. With the feet touching the ground, it's pretty solid. I can grab the table and shake it, and you get a little bit of a wobble, which is from the feet compressing. And if you aggressively spin the handle on the X axis, you get a tiny bit of rhythmic rocking in the whole setup, but only if you really go crazy with it. A lot of this is more because the base doesn't have a very wide stance. If the base was wider, it would help. Also, the rubber feet do give a very nice mechanical damping. I haven't machined anything yet, but you can tell that vibration and such will be damped quite well by having it decoupled from the floor. Once it's properly leveled and there's equal weight on each foot, I'm sure it will be more than stable for what I need.

Unless you plan on making your own beefcake stand, I'd do either something like this or hockey pucks. The problem with hockey pucks is that one of them is always going to have a lot more weight on it, or a lot less weight. So it's hard to make sure they all have the same load. If one doesn't have as much load, it could wobble a bit. In one of my posts I gave an overview of the total cost of doing a conversion. The casters were $80 for all 4, and around $15 or so for the metal. It's pretty cheap in the whole scope of the project. You could of course get really heavy duty leveling feet if you don't care about it moving for a lot less. I'd do SOMETHING to get it level. Also, the metal bars help to distribute the load across the whole cabinet.

Next weekend I mights start to tackle the oiling setup. I need to start getting some models drawn and getting the documentation together though.

[cowanrg]

Here are the documents that came with the mill. As others have said, the manual looks to be either outdated, or for a slightly different version (maybe the 20 or 25). Generally, it looks OK, but is missing a couple parts at first glance. Mine does have a gas shock in the column, which isn't shown in the diagram.

Also, here's the test report. This is the inspection report that each mill goes through.

When I was looking to purchase the mill, I tried looking everywhere for the manual and couldn't find it. So hopefully this helps someone out.

[AVRnj]

Very good point on the pucks, I would love to build my own stand, but without welding equipment I would probably have to do wood, which I am not sure would be ideal for various reasons. I may buy the same castors as you and be done with it. Maybe put a bunch of weights in the bottom of the stand for extra rigidity. Very curious to see what you do for an oiler, I need to do one as well.

[cowanrg]

Yeah, I might end up doing a sand bag or something in the base for a bit more stability. But, since there's 500 pounds sitting on top, I'm not sure if 50 pounds of sand will do a whole lot... we'll see. I think it's fine.

I'm in the same boat as you, I don't have a welder, and I would have either bolted a frame together, or used wood. This was a simple solution. If you check my blog post, I have the link to the guy I bought the casters from. Good guy. That's about the cheapest place I found, and they seem to all be the exact same thing.

[AVRnj]

Yes, I saw the link. I am going to buy them, seems like a pretty reasonable price. Thanks.

[cowanrg]

I ran into a bit of a hiccup. This weekend I'm working on getting the one-shot oiling setup going and when I took apart the table, I inspected the gib strips. They don't look good.

Both the X and Y axis strips have some discoloration at the ends, seems like they got too hot while grinding/cutting?



Although not idea, that doesn't really bother me that much. What bothers me is that the X axis strip looks like it just wasn't ground fully:

Attachment 228338

Here's a better look at the end. Yes, that's a big cut through the strip.

Attachment 228340

The Y looks pretty decent though. I don't have a surface plate yet, so I can't test how flat either really is. Here's what the Y looks like, and the backside of the X.

Attachment 228342

Any thoughts? I knew what I was getting into with a chinese machine, so if this is the worst I have to deal with, I'm OK. Should I request new strips from Quality Machine, or get a surface plate and sand/lap them down? Or is this normal...

[109jb]

From the two circles on the strip in question, I'm thinking that is the side toward the axis locks and is not the side that rides on the table dovetail. If that is the case I would not be too concerned. It looks like there is some rough finish on the one end, but it looks like the high points got hit by the grinding machine.

[AVRnj]

Took a closer look at my gibs, I don't notice any areas where it is not ground properly. I do however plan on lapping my ways and gibs as a part of my conversion. I decided the scrapping is going to be too much for me to take on for a machine this size, so I decided to do the method described on the mini lathe site with the polishing compound. Maybe you want to do that at least with the gib?

[cowanrg]

I think for right now I will leave it alone. The machine is going to be apart for quite some time, so it's not like I need to rush on getting it done right now. I'll be ordering a granite surface plate soon, so I could see how flat they are. Everything moves pretty smooth, if not a bit tight. I think it just needs some oil. I wiped off the grease, cleaned it up, and sprayed it with WD-40. I think with some way oil, it will move a bit better.

[cowanrg]

I've spend a good part of the weekend in Solidworks getting the mill modeled. I'm done with the table, saddle, x leadscrew, x nut, and the x mounts. Here are a couple glamor shots so far.

Attachment 228570

Attachment 228574

Attachment 228578

I'm still working on tweaking it a bit, with the rough castings it's hard to get proper dimensions, but as of now everything fits (in the assembly) and mates well. This should make modeling the ball nut mount a lot easier. Once things are more complete, I'll share it online so other people can use it.

[AVRnj]

Really nice work, blows my modeling away.

I have noticed a lot of people use solid works and other high end CAD software. I remember looking into solid works and it was around $2K.

Do you get through your job, or have you bought that? A little rich for me, but I would love to be able to design like that.

[cowanrg]

I have it through my job, which is ironic because my job doesn't require Solidworks... I just taught myself how to use it. BUT, student editions are practically free. But they don't have the rendering features though. Once I get it up on 3D content central, it has a nice exporter that you can use to download it an just about any format you want.

[SCzEngrgGroup]

Really nice work, blows my modeling away.

I have noticed a lot of people use solid works and other high end CAD software. I remember looking into solid works and it was around $2K.

Do you get through your job, or have you bought that? A little rich for me, but I would love to be able to design like that.

$2K? That must have been quite some time ago. I just bought it, and the cheapest version was almost $4K, but worth every penny.

Regards,
Ray L.

[AVRnj]

I just looked into the student version, looks like it is $150, but you have to show proof of being a student, which I am not.

Ray, regarding pricing, just looked again, that was for the standard subscription, the license is actually $4k.

From the looks of it, I can see how it is worthwhile for those who use it for business, but for me I don't know that I can justify $4k for hobby use.

[mduckett]

We have SolidWorks at work, truly a great product, but I can't afford for home/hobby, so I went with TurboCAD and got the CAM plug-in. If you get an older, but very capable version such as Platinum Pro 18, you can do some pretty good modeling. The CAM is 2.5D and ok/convenient. It also supports CNC lathes. Here's a link where you can get a full version 18 with the CAM plug-in for $299 (TurboCAD Pro 18 Platinum Edition with CAM Plug In Complete CAD & CAM Solution - TurboCAD Pro 18). --md

[AVRnj]

mduckett, thanks, I will check that out. I like the idea of having CAM integrated with CAD. I want to see if they have any free trials before I buy, thanks.

[cowanrg]

It's been awhile! I've accomplished a lot. I have the mill fully running, I just need to add some limit switches and such. I'm cleaning up the model right now, but almost everything is modeled. Here is the X bearing block assembly:

Attachment 245834

And here's the PDF with callouts for the individual components. Those are the McMaster part numbers, but they can be found elsewhere (like the bearings).

Attachment 245836

[cowanrg]

Here's the full post:

X-Axis Conversion

At the bottom are all the files for the X Axis.