[ackbar345]

OK. This is my first post about my first cnc router table build containing my first google sketchup project drawings of my design. This is my first 3D CAD work and my first CAD work since 2000 when I was in high school using an outdated at the time version of AutoCAD.

I based a lot of my design off of things I have read here, primarily Arbo's designs but drawing from a lot of the build logs I found on Ahren's site. I don't think I could have gotten this far without people generously sharing their knowledge on these forums, so thank you everyone!

Be gentle, it still a long way from perfect, but I thought this would be a good point to start getting some input. I already have most of the parts, except the steel rail and the router and mounting bracket for the router. I also have a few extra parts (do'oh!) because I started buying parts before I started drawing in sketchup. So if anyone is interested in some NEMA 23 motor mounting plates from cncrouterparts.com or a 60" piece of 1545 at discount rates, let me know.

This is a R&P table (x and y), approximately 54x45. Almost all of the parts are from Ahren with the exception of the rack (Moore), screw(McMaster) and a few odds and ends from Fine Line Automation(fasteners kit). I am using Ahren's High-Z plate with extended linear carriages. I still have some questions about my Z-axis lengths and the use of drill rod & couplers (optional? I have plenty of extra screw?).

Anyway, here she is, thanks in advance for your comments/suggestions.


-Mikkel

[CNC Lurker]

I like your plans, it is similar to an idea I had about making a Solsylva CNC with 80/20 extrusion. In the end I went the safe route and am building it like the plans on the CNC Routerparts & Fine Line Automation site. Sawdust (routerdust??) falling onto the cold rolled steel rails and jamming the ABEC bearings was a concern I have and mounting it on top like you have would alleviate that problem (along with a dust shoe).

As for the drill rods and couplers, you won't need those since you are making your own design. Their plans still call for the drillrods and lovejoys even though they now offer a helical shaft coupler. The drillrod also gives the ACME rod a little more usable length, but since they sell ACME in 3 ft and 6 ft lengths, you won't have to worry about that for your Z-axis.

[ackbar345]

As for the drill rods and couplers, you won't need those since you are making your own design. Their plans still call for the drillrods and lovejoys even though they now offer a helical shaft coupler. The drillrod also gives the ACME rod a little more usable length, but since they sell ACME in 3 ft and 6 ft lengths, you won't have to worry about that for your Z-axis.

Yeah, that's kind of what I was thinking about the screw length. I mean if I already have more than I need, why would I hack some off just to add another part? I am using Ahren's helical shaft coupler.


I did have a question about these thrust bearings though. I was watching the Z-axis video in the Aaron Taylor build log on these forums and he used a coupling to wedge the thrust bearings onto the top side of the bearing block. I was wondering if I needed to do the same on the top or bottom of the low profile bearing I am using with the high-z plate? I bought two sets of thrust bearings but only one shaft coupler... I am working off of the parts set Ahren lists on his site for an ACME axis but it doesn't really take into account the use of his newer high-z plate.

[ackbar345]

Work continues, mostly modeling at this point, but the machinist who is ordering my steel for me is trying to convince me that I need Blanchard steel? I know Ahren's plans call for 1018 cold rolled and that seems to be what everyone else is using? The cost difference is pretty substantial...

Also, Ahren's specifications for the high-z indicate that I could attain travels of up to 12" for my z axis. Do I measure that as the tip of the router bit with the z in the highest position to the top of my work surface? I am trying to figure out how long to make my extrusion/plate for the z axis.

[CarveOne]

Work continues, mostly modeling at this point, but the machinist who is ordering my steel for me is trying to convince me that I need Blanchard steel? I know Ahren's plans call for 1018 cold rolled and that seems to be what everyone else is using? The cost difference is pretty substantial...

Also, Ahren's specifications for the high-z indicate that I could attain travels of up to 12" for my z axis. Do I measure that as the tip of the router bit with the z in the highest position to the top of my work surface? I am trying to figure out how long to make my extrusion/plate for the z axis.

Blanchard describes the process for surface grinding the steel plate for precision dimensions and flatness. I used it on my Z axis but it is at least double the cost of standard cold rolled bar stock of the same size. A 24" piece cost around $45 a couple of years ago. I made two Z axis rails from it though. Regular CRS bar stock is what most people use for the rails.

Don't even think about substituting lower cost hot roll steel bar stock though. It won't work because of the factory scale and poor dimensional control. Even if you try sanding the scale off, as I did.

CarveOne

[ackbar345]

Don't even think about substituting lower cost hot roll steel bar stock though. It won't work because of the factory scale and poor dimensional control. Even if you try sanding the scale off, as I did.

CarveOne

Yeah, I had been warned off the hot rolled from lurking these forums. I ended up going with the cold rolled.


Also I picked up my router today!! Bosch, 2 1/4 HP, 8k-25k rpm, 1617EVS motor.

[Arbo]

Nice. I think I would go with a R&P on my Y, if I felt like pulling my Y rail off and going with a thinner one... but I hate the thought of hand drilling another piece of steel.

Though I'll have to mull over the advantages and see if it's worth all the work for me.

[ackbar345]

I ordered a mount for my Bosch from K2. I started a dry run assembly. It looks like I am going to come up short on some fasteners so my New Years plan is to get that order together and maybe make up the wiring harnesses. I would post pics but my crappy cellphone camera just isn't cutting it. I'll try to take a better camera home and post pics this weekend.

[ackbar345]

OK I still failed on the pictures but I did realize my ipod nano takes halfway decent video (for as tiny as it is)...

Not sure if I can embed video like this or not:


Next step is work on the Z-axis...

[lunchtrayrider]

looks great.

[harryn]

Hi - Looks like good progress. I am not sure about your cell phone camera, but mine needs a lot of light to take a good picture. The difference between marginal and an over abundance of light was amazing.

[ackbar345]

Quick update since I'm already late for work:

Z-axis dry run assembly

I'm still not sure what kind of fasteners to use to mount the other two linear carriages. I'll try to get that sorted soon so I can mount the assembly on the gantry rail.

[ackbar345]

Well it is wintry mix here and I'm just getting over the flu but I managed to get a little work done. To solve my fastener quandary for the z-axis I ended up tapping the gantry carriages to 3/8" and cutting a few more threads on some store bought SHCS to get a tight fit.

Unfortunately this is where things went a little wrong. I forgot that I was going to need one of those holes on the carriage to mount the R&P plate and I got so excited about having the z-axis mostly together that I went ahead and mounted it to the gantry. Long story short: gotta take it apart again again again. Lesson still not learned.

No sense in squaring the gantry since I still have to take it apart again. The Y movement is also a little rough, I need to make some adjustments to the bearings while I have it off the gantry to remove that fastener. Also I'm thinking I'm going to have to trim the z extrusion down a few inches and the acme screw as well.

[ackbar345]

There seem to be some small imperfections on one edge of my 4" 1018 steel. Needle file? Sand paper? Whats the best way to tackle a couple of burrs without making the situation worse?

[lunchtrayrider]

1. I think K2 machines to order, could be wrong, it is worth waiting for. I think mine took two weeks when i ordered it.

2.I don't know EMC but I am pretty sure that EMC is only up to 10.04 Ubuntu.

3. Regular DB9 cables from the store are going to have too light of a gauge of wire in them. Ahren's cables are 20gauge wire. you can get 18 gauge at radio shack in stock.

[eigstein]

your grind-y sounding z axis may be coming from the thrust bearings . we can't tell from the u-tube, but suspect you ran the threaded rod through the thrust bearings and did not use the piece of drill rod as shown in ahren's sketch ups . the drill rod makes a seat for the bearings and keeps them in line . ahren has never explained this in enough detail . if you think about it . you have 6 thin rings sitting on the edge of a screw . bad things can happen .

[ackbar345]

your grind-y sounding z axis may be coming from the thrust bearings . we can't tell from the u-tube, but suspect you ran the threaded rod through the thrust bearings and did not use the piece of drill rod as shown in ahren's sketch ups . the drill rod makes a seat for the bearings and keeps them in line . ahren has never explained this in enough detail . if you think about it . you have 6 thin rings sitting on the edge of a screw . bad things can happen .

@ DIYaholic - Yeah, my dad took him out to the hunting club for the weekend. I'm sure he'll attempt to be in future videos, cam whore.

@ eigstein - It appears the grindy noise and errant motions were due to a shoddy soldering job on that connector. All the cabling has been redone with shielded cable and with superior soldering (through extensive practice) this time. Also I re-tuned the bearings on the carriages, trimmed the excess off the Z and screw and installed the bushing bearing on the bottom of the screw. Seems to be running well at the moment.

I think I have the soft limits mostly worked out and the home switches seem to be working though I still need to mount them in a more permanent position. This morning I am working on wiring up the relay for the router.

[JayCop]

Ackbar man that thing is looking sweet. I have a few questions about your machine.

How tall are the legs?

What are your router mounts, mounted to? (The linear carriages?)

Can you upload the sketchup file? Please pretty please

[ackbar345]

Ackbar man that thing is looking sweet. I have a few questions about your machine.

How tall are the legs?

What are your router mounts, mounted to? (The linear carriages?)

Can you upload the sketchup file? Please pretty please

First I would like to direct attribution specifically to Ahren of cncrouterparts.com for all parts that are taken from his website. Many of his parts drawings are used in the rendering of my machine. He retains all rights to his drawings.

Second I would like to direct attribution and thanks to lunchtrayrider and Arbo (both of these forums) as I drew inspiration from both of their designs and valuable knowledge from their and other build logs on this site.

Third, to the members of this site who helped me through a couple of tough spots during design and construction.


http://dl.dropbox.com/u/19254565/cnc.skp

I am releasing this file under the Creative Commons 3.0 license. A summary of the license can be found here: Creative Commons — Attribution 3.0 United States — CC BY 3.0 Full text can be found here:
Creative Commons Legal Code

In answer to your question, the legs are 8" tall. The router mount I bought from K2. I had to modify it. I had my machinist (Jergen's Werkstatt, Garden City, SC) pop 4 counterbored holes in the plate that lined up with the 80/20 extrusion slots. This allowed me to use the flat headed version of the socket head cap screw (see this nifty chart from the intertubes) and some economy t-nuts to fasten it to my extrusion. I think, but I am not certain, this is a result of using the Ahren's high-z plate.


I believe this to be the most up to date and accurate version I have of the sketchup file but it is given without warranty and with no guarantees of safety or function.

[ackbar345]

It is cutting wood under its own logic but DAMN do I have a lot to learn! I already buried it to the collet and because I don't have a relay hooked up (extension cord plugged into router, relay gets here tomorrow hopefully) I couldn't get it stopped before it did what I suspect was some damage to the bearings. It is still running ok, and I suppose it was bound to happen as I was learning through experimentation. I am test driving CamBam now, trying to learn its in and outs and how they translate over into mach3. I still want to use sketchup if I can for my CAD work, but we'll see how it goes.