[flyinwilly]

I finally got started on my table replacement. I've been using an old rolling cabinet with a blower installed in the botton and exhausting out the side. It's been really beat up plus it's only for freehand work. However, it does run pretty clean so I thought the addition of a water tray would really clean it up.

I've been collecting parts for several months, motors, controller (g540), power supplies, switches, rails, etc. I am using V rails for the x axis, linear rails for the y and z, The drive will be 3/4" belt on the x and y and acme screw on the z. I am using 2 motors on the x.

The table is relatively small compared to most on these forums, 4 x 2 ft. This is for 2 reasons. One is I don't need a large table and second it would be extremelly difficult to do the downdraft with a large table. the exhaust can either be filtered or ducted outside.

The table will be built from 2x2 square tubing, 2x2 angle, 1x1 angle, and various strip stock. Panels will be 18ga sheet. I built the top and bottom rails and posted the pics. Getting them square and level was a lot tougher than I thought it would be.

I'll keep posting my progress. Any suggestions would be welcome.

Willy

[flyinwilly]

Been a busy day. Got the legs cut and installed. Also added the top frame to the assembly. Learned a good lesson today - you can't have enough clamps and they can't be big enough.

Used a borrowed laser level to square and level the legs and top. Worked great - lots easier than a bubble or water level.

Added 2 pics of the work.

More to follow.

Willy

[flyinwilly]

Got a little bit done today. I installed the water tray supports. I decided to make it removable since it's not that heavy without water. It should simplify cleaning sludge. I plan to put 3 baskets (each 1/3 of water tray) in the bottom of tray - just remove slats and lift out.

Just need to figure out where to put drain so tray will slide out.

The build is going very well so far. Hope it continues.

Willy

[WSS]

Looks like a good start! A 4X2 is a handy size. A high percentage of the work we do is modifying existing parts, all of them are under 2X2. Our next machine will be a small one.

Look forward to your progress, good luck.

WSS

[flyinwilly]

Had a little time today so I installed the blower supports. Since the bottom of the machine will be covered, I welded nuts on the bottom of the supports for the blower mounting bolts. There are rubber buttons on the bottom to isolate the blower.

The blower is a belt drive Lau rated at 950 CFM. I chose a belt drive to keep the motor outside of the machine. My previous table used a direct drive blower and I had lots of trouble with dust getting in the motor so this should solve that problem.

Pics attached.

Any suggestions welcome.

Willy

[flyinwilly]

Added the blower shield supports and the slag filter. These are the inclined angles in the middle of the frame (sloped from right to left in the pic) and the small opening at the left of the incline. This should catch any bits that escapes the water table and is sucked down to the blower. The filter will be a fairly fine stainless screen. I had a rudimentary version of this in the original table and it worked very well. My real hope is that the water tray catches most of the debris. A piece of sheet steel will seal off the blower from the upper part of the machine except for the filter opening.

The vertical pieces opposite the blower on either side will be the door frames to allow access to the blower. At the lower left side of the frame is the beginning of the exhaust tunnel. I plan to have 12x12 furnace filter on the outside of the machine for a final air filter.

That's it for now.

Willy

[millman52]

Had a little time today so I installed the blower supports. Since the bottom of the machine will be covered, I welded nuts on the bottom of the supports for the blower mounting bolts. There are rubber buttons on the bottom to isolate the blower.

The blower is a belt drive Lau rated at 950 CFM. I chose a belt drive to keep the motor outside of the machine. My previous table used a direct drive blower and I had lots of trouble with dust getting in the motor so this should solve that problem.

Pics attached.

Any suggestions welcome.

Willy

How are you planning to keep the dust/grit out of that sleeve bearing on the end of the blower shaft?

[flyinwilly]

Millman:

I had those same thoughts so I have some caps with wipers that I am planning to use. I don't know how long they will last or how effective they will be.

The original design was to use a blower with sealed bearings but I picked this one up on Ebay for $35.00. It might prove to be a mistake but at least it won't have cost too much.

I originally was planning on having filters on the outside of the blower intakes thus the 2 maintenance doors on each side of the blower. I hope the water tray will reduce the dust and grit to a level that won't require them but if necessary, I can add them later. It's also possible to add dust filter material under the slag screen since it just drops into the opening.

Only time will tell.

Willy

[flyinwilly]

Finished off the exhaust tunnel frame today. I extended it back so the neck of the blower slides right in. Might be a problem if the blower has to be replaced and a different size is used.

Build is going really smooth. Hope it continues.

Any suggestions welcome.

Willy

[millman52]

Looks like you are coming along nicely on your build. Shouldn't be long now till the real fun begins.

Once you start cutting & things begin to wear together all the weak links begin to show up. At least they did with mine. It would be so nice, before a build begins, to have a crystal ball!!

[flyinwilly]

Haven't worked on the machine for about a week but did manage to solve one problem. I've been looking for a tank to hold the quench when not in use. I thought I would use A RV water tank but they just won't hold any pressure. The water tray will hold about 9-10 gallons so I needed a 10+ gallon tank. Found the HarborFreight had their 11 gal air receiver on sale for $29 so I took the internet ad to the local store and picked one up. The problem with it is that it only has 1 inlet/outlet and I needed 2.

I machined a fitting to weld on the tank. I threaded it for 1/2" NPT which allows me to use standard copper/brass fittings. I drilled a hole in the top of the tank and welded it on. This tank is rated for 125 PSI but this must be the absolute max because the metal is thin. Couldn't be much thicker than 16-18 awg. Held my breath while I was welding hoping I didn't punch through. Pressure tested tank and it held perfectly at 120 PSI.

The feed tube is just 1/2" copper pipe. The fitting is a standard 1/2" thread/sweat fitting. I had to bore it out so the pipe would slide completely through. I then soldered the pipe and the fitting. The end of the pipe sits about 1" off the bottom of the tank. So I now have my air port and the liquid port. Air in - quench out.

Got to get going on the water tray this week and get this beast working.

Pics attached.

Willy

[flyinwilly]

Besides Ebay, where can you buy Sodium Nitrite ? What kinds of businesses use this stuff ??

I plan on making my own quench according to the formula I found here on the Zone. I need to have the quench before I'll use the tank and water tray (when I get it finished).

Any help appreciated.

Willy

[flyinwilly]

Finished up the cable track supports, cable tracks, and installed all the motor cables. It sure dressed up the machine not having cables running all over the place or held up with tape.

I originally planned to have the cable under the rail but when I decided to use the belt reduction, the motors hung down too far. So I had to build a rack above the rail but it turned out OK. Gave me a easy place to tie all the cable down. I drilled a 1/4" hole about every foot or so and tied up the cable with ties.

I used shielded cable with a drain wire for the motor cable so I hope this is enough to eliminate interference now that the cables are above the table. We'll know pretty soon.

The water tray is coming along nicely. Last big thing to complete.

Still need to do air filter, screen filter, torch holder and torch cable holder, limit switches, and some misc painting.

It's getting close.

Pics attached.

Willy

[WSS]

Looks like you will be cutting very soon! You have had a quick build when all said and done. Very nice. Would you call this a portable machine? How hard would it be to haul around to car shows and swapmeets? I can see some potential there.

WSS

[flyinwilly]

I guess you can call it portable if you're very strong. My guess is that it's pushing 400 lbs with everything on it. I can move it on the casters but I am now using 3' pipes and it is still heavy. Wouldn't be too bad with 2 people.

I was moving it around on dolly but the plastic wheels on the casters broke about a month ago. It was pretty much done at that point, maybe 50 lbs less than now.

Interesting idea about the car shows and swapmeets. Instant parts. I was thinking along those lines for art and craft shows but the power requirements and potential liability are issues to consider.

I expect the machine will run very clean, especially on thin material so emissions should not be a problem.

I'll see if I can get some scales and see what it does weigh,

Willy

[flyinwilly]

Completed the water tray and associated plumbing. This was the most difficult part of the build. I couldn't get any of the local sheet metal shops to bend the pan at a reasonable price so I built a brake which did a fairly good job. The only problem was that I had to cut some slots on the bend lines to reduce the force required and then weld them shut later. Had a few minor pinhole leaks which I rewelded and then put seam sealer all around the inside edge. Worked great - hope it lasts.

The other problem was attaching the inlet/outlet to the pan. Couldn't find a standard drain around 1" so I used a flange with a gasket and a liberal amount of gasket cement and bolted it to the bottom. It had 3/4" NPT and I came out with a street elbow into a barb fitting and then into 1/2' TYVEK tubing to the tank. I put a piece of 30 mesh stainless screen over the drain hole and secured it with the bolts that attach the flange. We'll find out how good it is when the sodium nitrite arrives.

Just a few minor things left to do. Need to wire the torch relay, install final air filter, add the torch cable holder, and the limit switches.

Pics attached.

Willy

[flyinwilly]

Finished the torch cable holder (almost-still missing a return spring) and the torch relay got wired. Both work well. Time to cut.

The sodium Nitrite arrived and I mixed up a batch of quench, loaded it into the tank, and proceeded to make scrap out of perfectly good sheet metal.

I quickly found out that your problems are not over once you finish the build. It's going to take a while to learn how to run this beast.

The good points.
The downdraft works very well - zero smoke and fumes off the table.
The machine moves very precisely - no jagged corners, etc. Very smooth cuts.
Water system works very well - no leaks and relatively quick to load and unload the tray. I use about 10lbs air pressure.

The bad (or not so good) points.

The air filter is WAY TOO Small. It restricts the air flow too much so I had to move it away from the opening. I still need to finish the shroud to go around the air filter frame. The filter catches the real fine stuff but the smoke / ionized fumes are released into the area and set off the smoke detectors right away. The interesting thing is that without the blower, I ran for 30+ minutes before they even peeped. The downdraft works. The filter in the pic was pure white when I started and 30 min later it was brown. I am leaning toward a flexible duct into a filter box with several much larger filters. I have several configurations in mind and will need to try them out.

I really need a pendant. Due to interference from the torch, I had to move the pc about 20' from the machine. Good thing I bought a 25' cable. It's very difficult to see the torch holder to zero it out (haven't put the limit switches in yet) or set a new home position.

Have a problem with torch not lighting every time. It lights when you hold it by hand every time but not when it's in the holder. It's a contact start torch and I had to modify the Sheetcam post processor to lower the torch to contact and then back to cut height. That part works OK but it still doesn't light every time. Any ideas on this issue will be appreciated.

Need some type of clamping system for small pieces of metal on the table. Got the tip caught severl times and moved the piece. Anybody got any good ideas about clamps for this ???

I suspect that I need additional grounding. I am going to sink a ground rod but I'm not sure where the machine is going to end up in the shop so I'm reluctant to drill a hole in the floor right now. I think I'll just run a ground strap to the nearest water pipe. I haven't had any problems with the machine electronics, just the PC.

I ran all my test cuts on 18ga mild steel at 150 IPM and 25 amps. Got a nice narrow kerf , no bevel, but more dross than I would like. I'll try some more setups and see what works best.

Still have a little bit of painting to do. My THC should be in next week and that might solve some of the issues with the torch. At least it won't move without an arc OK and it should reduce the dross.

Pat Patriot was the very first cut! He's about 4" tall and 8" wide.

Pics attached.

Willy

[flyinwilly]

Fixed 2 items from the not so good list.

I bought a ShuttlePro V2 off Ebay and used the Mach3 plugin for it. It works great. It has 15 buttons that can be assigned to almost any function and 2 wheels for jogging. the inside wheel is automatic and whatever axis you selected, moves at a set speed until you hit the stop button (make sure you assign a stop button). The speed is a little slow but maybe it can be changed. The outside wheel is a variable speed one that you must hold. Works great for the money.

The second problem solved is the torch lighting. It was moving up in the torch holder. Didn't move much but enough to keep it from lighting. A cable tie has solved the problem temporarily. Need to make a removable clamp. Been fooling around with the post processor in Sheetcam and I have it where the torch lights every time (at least for the last 20-30 tries). So much for the idea that you can't use a contact start torch. This one is making very nice cuts.

Still working on the new air filter. Decided to build a box that will slide over the existing filter frame. It will have at least two 25 x 16 filters to start out with and room to add several more smaller ones if necessary. I made a mockup out of cardboard and duct tape and it seemed to work ok. I am keeping the original frame on because I can use a flexible duct to the outside when the weather is warm.

I actually made some parts for the machine with the machine. I needed to build the belt guard so I drew it up in autocad, loaded it into Sheetcam, and had Mach3 cut it out. It was SOOOO EASY and all the parts fit together. Took about a minute to cut them out. The welding together took much longer.
Some pics attached.

Projects left - air filter, table clamps, and THC.

Willy

[WSS]

Hey Willy, found this on eBay, it is probably bigger than the table but looks like it would work. I have looked into the newer type with the donaldson round filters. They look like they would work as they have a bar that runs around the inside of the filter that "beats " the filter to drop the trapped dust etc. into a tray. Knowing that a portion is magnetic, we could use some sort of magnetic sheet that the dirty air passes over before it hits the filter, like an ionizer plate kinda thing.

Build looks great!

WSS

http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

[flyinwilly]

That's an interesting looking machine. It probably is bigger than my table.

I found a filter that uses a waterfall to clean the airstream. Its a pretty good idea, kind of a moving water table. You could put a magnetic plate in the waterfall and catch the washed particles. I'm using a rubberized magnet to clean the water tray and it works super. Just drag over the bottom and it picks up all of the particles - might work in a filter.

What I find amazing is not what the plasma generates but the quantity of crap, especially on thicker material. These things are really health hazards. All you have to do is look in the water tray and the filters

Machine is working very well. Just trying to nail down feed speeds, cutting heights, air presure, and current settings. I would like to get this done before the THC gets here so I have a benchmark. I've got good settings for 18 , 16, 14 gauge and 1/4 inch. Good kerf, very little dross, and a little bevel on the 1/4 ". The bevel is very good on some of the sides and a little more on others. I suspect this has something to do with the direction of cut and the plasma swirl.

As soon as I learn what I'm doing, I'll post a video.

Willy