CarveOne's Work Table CNC Router Build

[CarveOne]

Hi everyone,

It's time for a new cnc router build for 2009!

This time around there will be no purchased plans, no intent to singlehandedly stop the world recession with my own expenditures, and no fancy technological tricks up my sleeve.

Just a sturdy 49" x 97" work table from my 2008 work shop build, some steel box tubing and some steel flat stock. Add eight of Ahren's bearing carriages, 1/2-10 5 start lead screws, four Gecko G203V drivers, and DumpsterCNC couplers and anti-backlash nuts. The Xylotex 425 oz/in steppers will be salvaged from my first build. A breakout board purchase will be needed eventually but is on hold for later in the build.

This build will not happen in a flurry of activity due to poor economic conditions that will dictate what I can purchase and when. By late summer I hope to have it running and will decommission the Solsylva 25x37 machine and it will be available for sale with the exception of the stepper motors and the Xylotex controller.

So, I have a plan and it looks like the drawing below. I hope it's readable. If not I'll try something else.

The work table legs (six 4" x 4") are not shown in the end view drawing. The x axis rails will be mounted into five table top supports with ten 1/2" x 10" long all-thread anchors on 16" centers. In between these main anchors will be provision for eight shorter anchors to be used only if they are needed for tweaking the straightness of the x axis rails. Everything will be made adjustable in some way. The work table will be made stiffer, leveled, made flat on top, and square in all directions before adjusting the x axis rails. Then I will start building up the gantry parts. After that I will build the z axis assembly. I have allowed for raising the gantry rail by replacing two box tubes if 8" height is not enough. I doubt it would ever need more than 10" for my purposes.

Raucous laughter and criticisms may begin now --

CarveOne

[lovebugjunkie]

CarveOne

No “Raucous laughter and criticisms” from my end, you are doing what I want to start later this month. I will be watching your build. Post lots of pictures.

I have been playing with the idea of building a cnc router that would give me at least a 4x6 cut area. Plan on using most of what Ahren's sells. He has plans to offer R&P sometime early this year so most likely go with it. My build will be slow as I can only afford to spend an average of $200-$250 a month at it.

8020 was my first choice but I soon hit $1700 for the major 8020 components alone. Ahren suggested pallet rack, or work bench. While looking on line for industrial work benches and pallet rack suppliers I came across a local unistrut dealer that carries all the components I would need for the base frame which makes it easy for me to walk in and buy what I need. I would still use 8020 for mounting the x and y rails if I used unistrut. Also found an example of an industrial workbench that may work.

Have quite a few metal fabrication shops within 10-15 miles of where I live so also plan on seeing what they would charge to weld up a table frame made out steel that could be taken apart in four sections.

[CarveOne]

lovebugjunkie,

This one will be able to accept a 4'x8' sheet but will cut just short of 48" wide by about 5' and a few inches long. I will use the full length acme rods on the x axis and cut the third 6' rod for the Y and z screws. I'll have stops on the table to position the full sheet at one end and the other end hangs out about 2', or I just cut the sheet 2' short for no overhang. I'll know more about these dimensions when it has been constructed. I'll squeeze the most working area out of it that I can during the build. A lot of the bearing mount and stepper mount details for the lead screws haven't been considered yet. They will have to be mounted to the ends of the rails by bolts or welds. I have some ideas in my head that may work.

Your local welding shop can buy steel from their suppliers much cheaper than we can get at retail so that should help. Their labor and consumables costs will be offset to some degree by that.

Thanks for watching,
CarveOne

[Khalid]

Carveone..Nice drawing but i will suggest you to post a enlarge version so that it can be readable..
You are going to the right track but still i will suggest you to extend the machine so that it can cut 4' x 8' sheet...This suggestion is just to view your beautiful shop and forseeing the future requirements and needs...

One thing bothers me Your actual working Z-height will become very less...see the attached picture.....!!!!!!!!! supposing that the tip of router bit will go above the Z-axis mount plate(Black color)... If router bit can't go up, the working Z-height will further minimize..say ~4" or 4.5"
Hope you will post pictures as the development proceeds..
regards

[CarveOne]

Originally Posted by Khalid Carveone..Nice drawing but i will suggest you to post a enlarge version so that it can be readable.. You are going to the right track but still i will suggest you to extend the machine so that it can cut 4' x 8' sheet...This suggestion is just to view your beautiful shop and forseeing the future requirements and needs... One thing bothers me Your actual working Z-height will become very less...see the attached picture.....!!!!!!!!! supposing that the tip of router bit will go above the Z-axis mount plate(Black color)... If router bit can't go up, the working Z-height will further minimize..say ~4" or 4.5" Hope you will post pictures as the development proceeds.. regards

The acme lead screws only come in 3' and 6' lengths. I have the 6' length rods and will be limited to less than 6' of working area. A longer z axis will require rack and pinion drive that will cost more than I want to pay for. This size table will work ok for my hobby uses.

The only convenient way to make the drawing clearer is to attach the .dxf file. Enlarging the ,jpg file only makes it get less readable. I tried that before posting it.

I plan to increase the gantry height once I know more about how the z axis physical size works out. The height shown is about the same as the Solsylva machine's height including MDF waste board thickness. 8" is too low for sure. Up to 12" seems reasonable.

The x axis rails can moved outward from the table more and be able to cut to the edges of the 4' sheet width. Doing that may increase flexing tendencies though. Making the 2" long aluminum spacers 3" to 3.5" long may work ok though. That will make the gantry about 58" wide. If gantry flexing becomes an issue the 3" gantry rail can change to 4" and a larger box tube stiffener can be used. It will add more weight riding on the x axis rails. I think the rail mounting method can take it. We will eventually see if it works ok.

CarveOne

[ahren]

CarveOne,
I think you're on the right track. One thing I'd consider (if you haven't purchased rails already) is splurging for cold rolled steel, even if you have to wait a little longer for it. It is nearly double the price, but the dimensional stability is significantly better, both between pieces and within the same piece. If you've already bought the steel, you'll need to run the carriages back and forth a lot, and then re-tighten after the scaling has worn off. I wouldn't try to sand it off, as you probably won't get it even.

Let's see some pictures and specs on that table! A good base is an important part of a solid machine. I'm always on the prowl for a work table that is widely available for cheap shipping, as 8020 is a bit pricey for something that doesn't move.

Best regards,

Ahren
www.cncrouterparts.com

[CarveOne]

Ahren,

I already have the x axis rails but not the gantry rail. The flat stock I got from Fastenal is hot roll flat # 0953294 at http://www.fastenal.com/web/products...ex?sku=0953294 There is no scale on it, just a blue finish with a fine grained surface texture. Most cold rolled round and flat stock I have bought elsewhere has had some scale on it and a gray/black color finish. It also has hard spots in it that HRS does not have. CRS round stock does not turn as well as HRS in my lathe because of the hard spots. I stopped buying CRS round stock for that reason. It's fine for welding projects though.

The work table is home built from very straight 2x4 spruce pine lumber with a 3/4" MDF top. A lower shelf has 1/2" OSB for the shelf. The blocking under the table top is on 16" centers. It is already stiff, but I'm going to add stiffener blocks that will be glued and screwed in place at each of the six 4"x4" legs anyway. I have decided to add additional table top support blocking so there is one every 8" for the x axis rail anchor bolts. No worries about weak table side rails this way, and more anchor points. The table structure is screwed together with 3" deck screws. The work table currently looks like the image below.

The first thing I will add is leveling feet on the bottom of each leg. Then add additional blocking and bracing while the table is inverted on the concrete floor.

CarveOne

[ahren]

CarveOne,
No problem on the steel -- whatever works for you is great. Maybe it's a difference in suppliers. Most of my stuff comes from speedymetals, who quotes the following tolerances for the respective materials, which from experience seem to hold true:

http://www.speedymetals.com/information/material26.html

http://www.speedymetals.com/information/material28.html

Your work table looks good and solid. Keep it up!

Ahren
www.cncrouterparts.com

[CarveOne]

Originally Posted by ahren CarveOne, No problem on the steel -- whatever works for you is great. Maybe it's a difference in suppliers. Most of my stuff comes from speedymetals, who quotes the following tolerances for the respective materials, which from experience seem to hold true: http://www.speedymetals.com/information/material26.html http://www.speedymetals.com/information/material28.html Your work table looks good and solid. Keep it up! Ahren www.cncrouterparts.com

The stuff I have any experience with has been from the metals display from Lowes. Not sure what the pedigree is for that. I assumed that the pieces painted blue on the end is cold rolled and red is hot rolled. I just know that the red ones turn better for me.

The label on the two Fastenal flats I have also says A36. I see that Speedy Metals has CRS in 3-1/2" widths. I think I can use 3-1/2" width for both x and y axis. According to your carriage drawing, I can fit the 1-1/2" square box tubing stiffener between the carriages with comfortable enough clearance for the y axis carriages. The 3" width was going to be kinda close.

UPS charges for packages over 59" to N. Carolina may be excessive though. Will have to check on that before ordering three 72" pieces.

CarveOne

[CarveOne]

Today I picked up 2 ea. 1/2"-13 x 10' all-thread rods, 50 ea. 1/2-13 nuts, and 25 ea. 1/2" ID flat washers so that I can begin making adjustable feet for the table legs and cut the 10" pieces of all-thread for the x axis rails this weekend or whenever I get the chance to start on them before the weekend.

In order to drill the 1/2" holes in the table rail and support blocks squarely and deeply enough I'll make a drilling guide fixture that will keep the drill square with the 2"x4" table side rails and referenced to the top of the table. Then using the fixture I'll drill the holes as deep as I can with a 5" long brad point drill. I'll finish the hole to depth with a step-down shank brad point drill mounted into a homemade extension shank made of 1/2" hot roll steel round bar stock that has been reduced in diameter a few thousandths for ease of drilling a deep hole.

The table leg adjustable feet will be made of 1/2" nuts and washers that are tack welded to 8" long 1/2" all-thread rods. The rods will be inserted into 1/2" holed drilled into the bottom of the table legs. A 1/2" nut and a 1/2" ID washer at the bottom of the legs on the all-thread rods will support the table weight and allow leveling the table.

Photos will be provided of the fixture, drill extension, and leveling feet when built.

CarveOne

[CarveOne]

Some progress has been made this week on the drill fixture and I made the mild steel 0.50" ID x 0.875" OD insert this morning and epoxied it in place. All of these parts required close tolerance alignment so that the 1/2" holes in the table will be correctly drilled for the x axis all-thread support rods. The whole CNC router project depends on the x axis rails being in perfect alignment in all directions. Don't need to be using a 10 pound maul to "tweak it into alignment" in order to salvage the mess I made due to careless drilling. The drill fixture will be clamped to the table top for drilling the support rod holes through the pine spacer blocks, pine 2" x 4" table side rails, and into the table top support blocks. With luck and patience the holes will go where I want them to. The drill bit is a 1/2" brad point type with a 1/4" shank. I will need to make a drill bit extension from a piece of 1/2" OD mild steel round stock so the drill can reach the full 9" depth that will be needed.

I also made four of the 1.5" diameter x 2" long aluminum spacers for the x axis rails this morning and will make at least six more later today. Not sure that I will need the spacers on every support rod but if I can make enough spacers from the 36" piece of material I have on hand I'll add them.

I expect to cut the all-thread support rods to length today. Tomorrow I hope to drill all of the holes in the work table and insert the support rods.

CarveOne

[CarveOne]

Old CarveOne can make lots of metal chips too!

Spent the afternoon drilling and cutting off ten of the aluminum spacers to within 0.001" matching lengths. The remaining material may produce three more spacers so I will save it for some future project instead. There will be five support rods with spacers and four additional 1/2" support rods with no spacer on each x axis guide rail. If this is isn't rigid enough I'll buy more material and make more spacers.

No time left for cutting the support rods today so that will be done tomorrow. I'll cut the six shorter rods for the leveling feet also.


CarveOne