Congrats Don my friend - I know that you have wanted to do this for a long time now.
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| And so it begins... http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10106&t=16279 |
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| Author: | Don Williams [ Thu Mar 06, 2008 12:27 pm ] |
| Post subject: | And so it begins... |
Well, the bench is complete enough to start cutting aluminum extrusions, and all parts are either in hand or on order. So it finally looks as though I'm ready to attempt to take this pile of mess and turn it into a cnc router. Here's a few pics of the parts... |
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| Author: | Jeremy Vonk [ Thu Mar 06, 2008 2:01 pm ] |
| Post subject: | Re: And so it begins... |
Looks like fun! Do you plan to document the process here? Good luck! |
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| Author: | Hesh [ Thu Mar 06, 2008 2:05 pm ] |
| Post subject: | Re: And so it begins... |
Congrats Don my friend - I know that you have wanted to do this for a long time now.
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| Author: | Don Williams [ Thu Mar 06, 2008 2:45 pm ] |
| Post subject: | Re: And so it begins... |
Thanks guys. I'm planning on documenting as much as possible. I plan to take pictures throughout the project, and hopefully you folks can get the benefit of my frustration. I mean my experience.  
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| Author: | Jim Watts [ Thu Mar 06, 2008 2:49 pm ] |
| Post subject: | Re: And so it begins... |
Looks like fun Don! Please give us updates on your progress. |
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| Author: | npalen [ Thu Mar 06, 2008 4:12 pm ] |
| Post subject: | Re: And so it begins... |
Don--Has your better half seen all this?
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| Author: | Don Williams [ Thu Mar 06, 2008 4:27 pm ] |
| Post subject: | Re: And so it begins... |
Nelson, in fact, she WANTS me to build this. I told her I could use it to make Christmas presents for this coming year. That's all she needed to hear, since she hates to shop. My Girl !  In truth, the only reason I'm building this is to be able to make a backgammon board. I figure it's the easiest way to cut out all those triangles accurately. After that, it may just sit there unused. Yep..........World's most expensive backgammon board. 
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| Author: | Hesh [ Thu Mar 06, 2008 4:30 pm ] |
| Post subject: | Re: And so it begins... |
Don Williams wrote: In truth, the only reason I'm building this is to be able to make a backgammon board. I wonder if Tony Soprano would get in trouble at home if he bought a Laguna and a case of garbage bags............
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| Author: | Parser [ Thu Mar 06, 2008 5:37 pm ] |
| Post subject: | Re: And so it begins... |
I'm very sorry to hear about this addiction, and I hope you find the strength to kick it. But in the meantime...please keep us updated! |
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| Author: | KenH [ Fri Mar 07, 2008 12:20 pm ] |
| Post subject: | Re: And so it begins... |
You are certainly going first class Don! I look forward to seeing pictures of your progress! Ken |
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| Author: | Don Williams [ Fri Mar 07, 2008 12:49 pm ] |
| Post subject: | Re: And so it begins... |
Hodges_Guitars wrote: You are certainly going first class Don! I look forward to seeing pictures of your progress! Ken Now there's the real sickness. OCD at it's finest. I can't do something "simple"...I have to go virtually all-out. But there's a limit to my madness I guess - I didn't go straight into servos, as I figured it would be more difficult to get set up for them properly. Perhaps someday I'll change over to them, if I ever see a need to do so. I doubt it, but you never know. And they were going to be a lot more money to get good ones anyway. BTW, I never could get that file to open... |
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| Author: | Tim McKnight [ Fri Mar 07, 2008 8:53 pm ] |
| Post subject: | Re: And so it begins... |
Don, What is your cutting area dimensions going to be? How much do you have invested in that pile, if you don't mind me asking? |
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| Author: | Rich Schnee [ Fri Mar 07, 2008 11:10 pm ] |
| Post subject: | Re: And so it begins... |
So what is the plan??? A fixed gantry system or a mobile gantry??? What are you using for linear motion??? Those ball screws suggest that money is not a concern. Are you posting your progress in the CNC zone forum??? Looking forward to seeing this project come to fruition…please do share with us. |
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| Author: | Don Williams [ Sat Mar 08, 2008 1:05 pm ] |
| Post subject: | Re: And so it begins... |
Let's see... The actual cutting area is roughly 31x50, so it's big enough to do a 1/4 sheet of plywood, which will help when making things like outside molds etc. Mostly I'm concerned about having dedicated locations for various operations. The gantry will move, but unlike a lot of designs, it will be a long gantry moving a short distance. It fits better in my shop that way, and affords me some functionality that I couldn't have otherwise. I'm using linear rails for the motion, and a THK KR33 actuator for the Z axis. The long linear rails are 57" long, and the short ones are 39". I'm using two motors and ballscrews mounted at opposite ends to drive the gantry back and forth, rather than a single screw mounted in the middle. This give me the ability to mount things underneath the table, such as necks to cut dovetails with, or a body to cut a fancy end graft with, etc. Tim, I will have to sit down and figure out exactly what I have into this thing. I'm sure it's more than I planned! I'll let you know when I get it all figured out. The ballscrews....well, they were definitely the most expensive element, but most everything I got off eBay otherwise. Homeshopcnc.com has some pretty good prices on their ballscrews, but mostly the price of their end support blocks is what stands out. They are half what other places charge, and in some cases, even less than that. By no means would I say that money wasn't an issue for this. I had to part with a lot of wood I wanted to keep in order to afford it all, so it was a big trade-off me. I hope to post to the CNC Zone as well...yes. |
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| Author: | Rich Schnee [ Sat Mar 08, 2008 3:08 pm ] |
| Post subject: | Re: And so it begins... |
Ok…I am doing a little math and I see that your Y axis being 39” travel with a usable cutting travel of 31” will mean you are using a gantry that is 8” in width that spans 57” in length, a major racking issue so I assume you are using ball screws on each end to keep the gantry from racking? That will open up the underside nicely but are you going to use a single servo to drive both ball screws or are you going to try two servo’s and drive each ball screw separately and keep them synchronous? What is the plan for your X axis? Another ball screw? I have given building a CNC allot of thought. I have considered suspending the entire machine above the work table. Just imagine the router facing up and then turn the machine up side down. This would open up a tremendous amount of unimpeded work area. The only thing connecting the machine to the table would be four posts in the corners. You then can build a gantry as stiff as possible. The constraints of this design a few. |
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| Author: | Don Williams [ Sat Mar 08, 2008 6:17 pm ] |
| Post subject: | Re: And so it begins... |
Yes, I have two separate motors driving two ballscrews, one on either end of the gantry. Each motor has its own Gecko drive. Steppers, by the way, not servos. The X axis has one nice big long ballscrew. I'm not intending to drive this thing very fast, so I don't anticipate whip being an issue. If it is, then I'll rig up some kind of UHMW bearings to ride in the 8020 aluminum extrusion channels to provide some extended support. It would limit the travel by a few inches though, so hopefully it won't be an issue. I've seen systems as you describe on the Zone. One guy in the UK built a frame that was cantilevered from a wall. It was pretty cool. |
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| Author: | Don Williams [ Sun Mar 09, 2008 1:27 pm ] |
| Post subject: | Re: And so it begins... |
Update.... I have almost all the 8020 aluminum extrusions cut to length, and the gantry uprights assembled. It moves along pretty fast once you get started... Pics later. |
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| Author: | Don Williams [ Mon Mar 10, 2008 6:15 am ] |
| Post subject: | Progress ! |
Well, all the aluminum extrusions are cut, and most of the 1/2" plate as well. I'm probably going to end up taking some of the plate to a local machinist to have the holes drilled out and some surfacing done for the motor mounts. The problem with extruded plate is it tends to not be that straight, and it also tends to cup slightly. The ground stuff is way better for flatness, but it costs a small fortune in comparison. So here's a couple pics... |
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| Author: | Don Williams [ Mon Mar 10, 2008 6:25 am ] |
| Post subject: | Re: And so it begins... |
The 8020 Inc. aluminum extrusions are great. They weigh a ton, and are very easy to cut and bolt together. This stuff is basically a grownup's erector set. A little cutting lubricant, and a chop saw goes through it pretty easily, unless you have a clamp in the way of the saw head. The you start to wonder why on earth the blade won't cut the material, like somethin's causing it to hang up somewhere.  Anyway, after getting the first section assembled. I decided to throw my trusty framing square on the unit to see how badly out of square it was. The weird thing....it was dead square. In picture # 3-cnc, there is an opening that is 21" wide, by about 9" deep. That is where I will mount a plate that drops down under the cnc to hold necks and rims for cutting dovetails, tenons, mortices, and endgrafts etc. I figured I would design the fixture around future usage right from the start. Seems to make some sense. |
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| Author: | npalen [ Mon Mar 10, 2008 10:05 am ] |
| Post subject: | Re: And so it begins... |
Don Good "forward thinking" on the hole in the table for fixturing. You may end up with a true "luthier's cnc"! I would certainly encourage you to continue checking and double checking everything for flat, square, runout etc. Effort put in at this stage of the game will pay dividends down the line. You can machine your table and/or fixture plates later to get them "true" to the travels but if something in the frame is warped or twisted......... ![[headinwall]](./images/smilies/headbangwalluf8.gif "Mad") Interesting stuff!!!!! Nelson |
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| Author: | cyborgcnc [ Mon Mar 10, 2008 10:12 am ] |
| Post subject: | Re: And so it begins... |
Congrats on starting your build. I have build a "solsylva" machine from wood, and the results I get from it exceeded my expectations (especially on guitar making). Best of luck with your build, and if there is any help I can provide (especially from a software standpoint) please do not hesitate to ask. Thank you for sharing the build with us. One question: What spindle are you going to use? From your pic, it looks like some sort of a High Frequency spindle, I was wondering what controller are you going to use, and what the spindle is? 
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| Author: | Don Williams [ Mon Mar 10, 2008 11:21 am ] |
| Post subject: | Re: And so it begins... |
npalen wrote: Don Good "forward thinking" on the hole in the table for fixturing. You may end up with a true "luthier's cnc"! I hope so! we shall see. I've tried to think of things I woul duse this for, and then incorporate them into the design. Hopefully it will not require too many changes down the road. npalen wrote: I would certainly encourage you to continue checking and double checking everything for flat, square, runout etc. Effort put in at this stage of the game will pay dividends down the line. You can machine your table and/or fixture plates later to get them "true" to the travels but if something in the frame is warped or twisted......... Interesting stuff!!!!! That's for sure...I'm already finding myself checking for level and square everywhere. I can't think of anything worse than cutting a square and having it turn out to be a non-square parallelogram instead... 
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| Author: | Don Williams [ Mon Mar 10, 2008 11:29 am ] |
| Post subject: | Re: And so it begins... |
cyborgcnc wrote: One question: What spindle are you going to use? From your pic, it looks like some sort of a High Frequency spindle, I was wondering what controller are you going to use, and what the spindle is? I'm using a Porter-Caple 893(?) for the primary router, and I also have a little mini-spindle from eBay that I hope to use for inlay work. See the thread here. |
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| Author: | KenH [ Mon Mar 10, 2008 10:00 pm ] |
| Post subject: | Re: And so it begins... |
It is looking good so far Don! Please keep us posted on your progress. My new acme screws and nuts still havent arrived, but I am expecting them tomorrow. I hope this solves some of the issues I have been having with mine. I am really interested in how you design the glides for your mill. |
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| Author: | Don Williams [ Tue Mar 11, 2008 9:25 am ] |
| Post subject: | Update 3/11/08 |
Latest update: Last night I spent only a little time as work pretty well exhausted me. I managed to get another section assembled and attached to the base assembly. I also tapped the first hole of many... The 8020 extrusions are really well engineered. The holes in the ends are the perfect size to tap for a 5/16-18 thread. It's just a question of a little lube and tapping, which goes pretty quickly. I'm dealing with trying to decide how I'm going to handle the machining of the aluminum plates for tying the base together, and also the plates for mounting to the linear rails and also for the spindles. I'm really a fan of precision, and getting things to align perfectly. That said, the real world doesn't often hold to those tolerances, and getting an assembly to exactly match a drawing isn't as easy as one wood think. This isn't house construction where one gets to within a few 8th's of an inch and calls it dead on...this is machining to much tighter tolerances. Anyway, so I'm debating using a machine shop to make the parts, or cutting them temporarily from plywood and making the aluminum versions with the cnc, or just trying to machine the aluminum plate with my drill press. Ick. I'd like to keep the spending under control, and at $65/hr, the local shop sounds like it could get real expensive, real quick. Here's a few pics of the latest progress: Tub O' Lard to anyone who can figure out which of the parts is a sheet of paper lower than the others.... 
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