[hcsceo]

I got my first CNC today. It was a build someone else did and sold to me. I'm pretty sure it is a HobbyCNC and as far as I can tell it is stock. It might be based on a previous version as it doesn't have the vacuum top. Came with Xylotec 3 axis controller, power supply, 3 bipolar steppers and all cabling ready to go for about $110. It has been in storage for a while so the linear bars are a little bit rusted and the thing was a mess as he used it a lot when it was running. I took it apart tonight and cleaned everything. I'm going to get some steel wool tomorrow and clean up all the metal stuffs.

My question is this. Since I have it apart should I upgrade anything or just clean it up and run it and modify later? The linear bearings look like brass bushings and the screws are all 1/4-20 standard stuff you would find at a home store. I haven't run it yet as I wanted to clean up the surface rust on the linear rails and clean up the machine generally. I probably could have it running like it is in a couple of days.

[CarveOne]

I would recommend getting it running first and seeing where the problems show up. Then figure out what you want to do to correct it.

Post a couple of photos of it assembled so we can see what you are working with.

CarveOne

[hcsceo]

Cool that's what I was thinking to. I'm loading a spare computer now with EMC and I'll get the CNC completed in the next day or two and post pics.

[CarveOne]

Cool that's what I was thinking to. I'm loading a spare computer now with EMC and I'll get the CNC completed in the next day or two and post pics.

Cool, that's what I'm running also.

CarveOne

[electric2u]

i'm going to start build my first cnc router this weekend think the size is going to be around 20 x 32 or so what size thearded rod do you think i should get and how accurate is it like with in 1/16 or so

[hcsceo]

OK I got it cleaned up and back together tonight. Honestly, I'm surprised with how simple the machine is. I got it hooked up to the computer and setup with EMC2 which was super easy since the xylotex controller had settings preconfigured. I'm still working on the velocity and speed but that should come quickly.

After doing a couple of tests it is clear I have a problem with the top. It isn't flat and appears the previous guy must have stored it with something sitting on top of it. It kind of slopes to the middle and to one side. What is the best way at this point to get it flat? I could easily replace the wood top with another, but is there a better solution? Is milling the top with the router on the machine an option? Any ideas would be welcome.

[hcsceo]

What about a 3/4 plexi top?

[jalessi]

Milling the work surface will work fine, the only issue is it will have a ridge where the X and Y travel ends.

If your work does not overhang the surfaced area you will be golden.

A 3/4 inch thick piece of plastic the size of the work surface may be a solution however will cost a small fortune.

Jeff...

[hcsceo]

Thanks Jeff I think I'll give that a go then. That would ensure the top is square to the router. I could go down the sides with a flush trim bit on a hand held router and probably get the ridge off enough to make it work for small overhangs. 3/4" Plexi in 12x36 is about $75 shipped. Milling the top $0

Steve

[jalessi]

Steve,

Maybe you can find a Zone member in your area with a larger router that would machine your entire old surface for you. Taking the top off should be a fairly simple task.

What ever you decide make sure you seal the top after you machine it, humidity will damage it in short order.

Jeff...

[ger21]

I think if you machine the top it will just sag again. I'd make a new top with plastic laminate on both sides, which will make it much stiffer.

[jalessi]

I agree with Gerry about the sag recurring, why not go a step further and make the top out of .500 aluminum plate.

[hcsceo]

Yea I'm still haven't decided. I'm down to two choices at this point. Either replace the top with another wood one while I'm learning the machine and move to aluminum later. This would be the least expensive and I couldn't use a premade formica counter top and cut it down to work. The other option is to get the aluminum now. If I'm willing to drive 45 minutes one direction, I can get a peice of .50" 12.5x30 aluminum for $49. It has a few drilled holes in it but will be fine for my purposes. I'd have to make the CNC 6 inches shorter but it should be really easy to do and I don't think I'll miss it. I've put in a call to the local waterjet companies as we are regular customers and they are all looking through scrap for possibilities and I'm going to check the recyclers. The guy that runs our mill at the office said he would mill anything flat I brought to him if it fits on his machine. Finally there is a Corian dealer close to my house that has a lot of scap available for almost nothing. I thought I'd look at that product also.

[hcsceo]

OK I've looked for Aluminum and it is just more than I want to spend right now, unless I buy recycled. Finding a recycled peice about that size is difficult at best and I'm finding out that the ones I do find are less than ideal and will take a lot of milling to get right. I think I've come up with a solution that will work well for now.

I'm going to cut a 12x36 .75" MDF and dado out four .5" channels along the length and install four .5" square mild steel tubing. Then install a removable .5" mdf top that can be milled flat and also used for a sacraficial top. I think I have all the wood available at home and the mild steel is cheap.

I'm planning to install it permanantly into the lower section of one of my workbenchs in an area that is about 24" deep and 48" long. I'm planning to enclose that area for it and install a light, power strip, air connection, window, and shop vac connection. I need to devise a way to level the CNC when in there.

I'm also wanting to buy a new laminate router for it this weekend. I'm looking at the dewalt one carried at most home stores for $79. The router it came with is a crap rechargable deal that can only do light engraving at best.

[jalessi]

Sounds good to me, is it finished yet?

[milhead]

Hi Steve;

I have a machine I built similar to yours and I recommend that you not mess with machining the surface you have.

Get a peice of 3/4 MDF and pre-cut it to just fit within the area that your machine can cut. Screw the material down on your existing surface then you can fly-cut the whole top with your router.. It makes the leveling process pretty easy as the resulting surface is square to your router setup unless youve got some sort of torsional twist.

This peice of spoilboard will get all chewed up anyway when you cut through things.. When it get's bad enough you just pitch it, slap on a new one and re-level... I normally can re-level mine several times before I have to pitch it.

This makes your spoilboard slightly higher than the machine table and you don't have to worry about the ridges at the sides...

Mil

(p.s. I countersink my screw in at least 3/4 of the material so that I don't have screw heads to interfere with my router bits unless I make a 0.5 inch too-deep mistake)

[hcsceo]

Yea millhead this is exactly what I was thinking with the 1/2" mdf on top of the 3/4 one. I think it is the best solution and I can change it out and relevel it at anytime using my router. It's cheap, fast and should offer a level surface in relation to the router.

[jalessi]

Sounds awesome, is it making parts?

[hcsceo]

Sounds awesome, is it making parts?

LOL, stop talking.. make something.. I get it. I'll cut something useful over the weekend for sure.

[jalessi]

Hey someone has to clown around, it might as well be me.