[ger21]

If you want a lighter torsion box, it's best to lighten the internal framework and use thinner skins. The skins give it it's strength, so cutting holes in the skins will weaken it.

[Madclicker]

If you want a lighter torsion box, it's best to lighten the internal framework and use thinner skins. The skins give it it's strength, so cutting holes in the skins will weaken it.

I did use use lighter internal ribs than most do...1/4" MDF. I also used 1/8" tempered hardboard for the skins...don't think you can get much thinner without going to sheetmetal (or paper ).

I didn't cut any holes in the skin to lighten the structure. The lightening holes I cut were in the top and bottom hard edge that's 3/4" MDF. This was to be the connecting hard points for the top and bottom pipes. These holes are actually "skinned" over with red oak now....pic 1. The holes I cut in the skins were for bolt access. I have changed my design and will use through allthread to attach the pipes and supports. I was shy of this because of all the use I've seen of this stuff to tie gantry sides together and replace lower gantry TB's. Never considered this good design. I think it will be OK to mount the pipes like this, though.

I have laminated over the old holes and you can see this in pic 2. Only the bolt hard points to the gantry uprights have access holes now.

Had to include a 3rd pic to show how the red oak pops with my magic oil.

[Madclicker]

Didn't get much done today....had to go to wally world to resupply the fort.

Only pic shows reassembled gantry mock, this time with completed upper and lower TB's. When I have the Z trolley figured out I'll be able to determine the geometry of the gantry uprights.

Tomorrow I hope to mount the Y pipes and supports, then the construction of the Z will begin.

Do I see a light at the end of that tunnel?

[Madclicker]

Chisled out the HV coils of one of my trannies...the largest. Didn't mess up the insulating paper too bad getting the coil out, but the flux shunts were stubborn. Pic 1. You can see the mangled shunts and paper.

I wrapped 10 coils of 10 ga insulated wire in the secondary hole to test what the ratio was and got 9.24 Vrms. Second pic. I now think there is enough room to just rewind the secondary with the 10ga insulated wire and save the magnet wire for another project.

[Madclicker]

I'm shooting for a 60Vdc supply. Unless I'm wrong(and tell me if I am!):

((DCVout + Vdd)/1.414)/Vsw = #SecWinds

Where:

Vdd = V diode drop across the bridge (1.2V)

Vsw = Vrms of single tested secondary winding

Should give me a close count of the secondary windings needed?

[Madclicker]

Got my can caps today. Huge 60,000uf 75v Beasts.....but only $7 each delivered.

This motivated me to finish winding the secondary of my microwave tranny. Ended up with an output that was about 62V peak-peak. Should give me ~60Vdc supply with ample current.

Only parts left on the PS are the cap mounts and rectifier bridge.

pic follows.

[ZipSnipe]

Need to get ya shop boy and clean up that shop... Just jokin looks like my shop

[randyf1965]

[QUOTE=Madclicker]Got my can caps today. Huge 60,000uf 75v Beasts.....but only $7 each delivered.


Where did you get those caps?

[Madclicker]

Got the caps on ebay. Paid an extra $5 for the buy-it-now because I didn't want to miss out. Got 5, but one got dented in shipment. I'll probably resell the one's I don't use back on ebay.

[Madclicker]

Updated my expenditures:

3/4" MDF $83
1/4" MDF $24
Tempered Masonite $15
VT Laminate $69
NEMA 42 1390 oz/in stepper $25
NEMA 34 630 oz/in stepper $43
NEMA 34 400 oz/in stepper $24
Lovejoy's $15
Red Oak $30
T-Track $70
UHMW PE $10
2" EMT $16
Gas Pipe $10
4 5/8" flange bearings $30
2 3/4" flange bearings $15
5/8" ACME rods $20
3/4" ACME rod $13
4 Heavy duty castors $17
2 X 1 X 1/8 AL channel $10
abec-7 skate & R8 ZZ bearings $44
Can Cap $7
Cap Mounts $5
Rectifier Bridge $5
Magnet Wire $10
Misc. Hardware $50
3 Gecko's $400 (tentative)
-----------------------------------
Total $OMG

[2muchstuff]

I got my 5- 60,000uf 75 volt 95 surge caps from a guy on ebay for $20. I missed the auction, starting bid was $15 with a buy now for $25. Contacted him and got them with horizontal clamps for $20. Not too bad for someone who put the caps in the wrong section on ebay.

madclicker,

It doesn't seem like a lot of money when you nickel and dime it here and there but when you add it up in the end, -OUCH-.

[Madclicker]

Sounds like the same caps and maybe the same seller. Great deal!

So far, the nickle and dime approach has worked well. No big hits to the wallet. I will take a big breath and a big hit to the wallet soon when I have to buy the drives.

Got my lovejoys today. Pic follows.

[2muchstuff]

The guy that I got my caps from is north of Kansas City, Mo. He said that they were pulled from a 48 volt power supply used for telecommunications. The caps are made by Lorain. I'd take a picture of them but the camera battery is dead and the charger has grown feet.

[Madclicker]

Gathered a few things together today. Gonna have to build a control cabinet soon....hate the prices of off the shelf. Time to start pulling this thing together.

Got my BOB a while back but had to order a gender changer for it to work. Was sure I had one around here...but not. The parallel cable is old stock and I consider it a freebee.

I built the computer from back up stuff. Just a 266P2. Will run turbocnc fine from what I understand. The 15" lcd monitor was a gift from my brother. I will build an enclosure for the "brains" as soon as I get the machine earning it's living. Plan on 2 joysticks for X, Y, Z, and A. Paid $10 for a new HP opt mouse. Still need a KB and wireless net card.

Found 2 old P1 heatsink/fans and 1 heatsink that I had robbed the fan from. Gonna try to make these into a cooling system for the geckos. Just hope I can find 1 of the dozen tubes of heatsink grease I know I have.

As I said before I have rewound a huge microwave trannie and obtained big caps for the PS. Gotta order a big rectifier bridge soon. I also found a small switching PS from my college days and it still works. Will supply my 5V and 12V.

[JohnnyYuma]

Vary Vary nice Build, Keep it coming

[Madclicker]

Got a little more done today on the gantry. Got the 1.25" EMT mounted with 5/16" all thread through top to bottom. Cut the all thread a little long. I think I will replace the nuts I used with nylocks and then cut the bolts flush with a die grinder. The pipe supports are 7/8" al channel...looks good to me!

[Madclicker]

Worked on the drive box today. Gonna use an old AT case I found while dumpster diving for shipping materials. A cold chisel made short work of removing the drive cage and PS shelf. The original PS was toast or I would have just used it for the 5V and 12V I needed. Since it was, I took the cover off and used a grinder to separate the back that contains the fan and power sockets from the electronics. I screwed this back into the inside of the case. This can be seen in the first pic.

My gorilla tranny just barely fits in the case. Pic 2.

I made horizontal cap mounts from 2" Al channel and cable ties. Pic 3.

I was able to mount my BOB to one of the card slot thingies. Had to use a dremel and sanding drum to trim the PCB of the BOB to make it happen, but it was simple. Pic4.

[Madclicker]

I worked on the gantry trolley yesterday and today. My intention was to just build a prototype from 1/2" MDF and after I worked out the bugs make the real trolley out of 1/2 baltic birch. I've been saving 1/3 sheet just for this. Because this was intended to be temporary I just butt glued the joints together. I would use proper dado joints on the real one....but. The thing is so strong, square, accurate and glides so well on the Y pipes that I'll probably use it for at least a while unless I really mess up the Z axis. Hope I can put a decent finish on it. Pic 1.

I received my bridge rectifier yesterday, so I can finish the power supply. I'm also on the verge of ordering the geckos, so I started gathering up the wire I have around. Pic 2.

[Madclicker]

Made some lead nuts from steel nuts and MDF. These were just down and dirty hacks to get me going. There was a link somewhere that showed how much more efficient plastic nuts were than steel on steel. Something like 30-50%. Can't remember who posted it or where.Pics 1, 2 and 3 show the construction. Self explanitory. Used yellow glue on the MDF and a couple dabs of JB to hold the nut secure. Made 2 5/8" and 2 3/4". I absolutely had my gantry carriage and will make nuts from UHMWPE when I redesign it.

I turned the ends of 2 of the screws to fit lovejoys and also made taps for future use on the plastic nuts. Mounted 2 flange bearings on MDF drops and clamped them to my assembly table. Used my 3/4" drill motor to power my "lathe" on one end and "turned" the other end with a small angle grinder, Pic 4. Pic 5 shows the rough tap I made. Just have to use the die grinder and cut-off wheel to make cutting grooves. Pic 6 shows one turned end and pic 7 shows the mounted lovejoy after I ground a flat.

The last 3 pics show the new router table I built for my table saw wing. It replaces the first I built that was 48" and just way too big. Sometimes distractions are a good thing.

I've actually done much more...just don't have pics yet. Gonna order the Geckos tonight and I think I have everything to get this albatross flying very soon.

[spalm]

Looking good, Steve.

I see that you mentioned that you are just using the nuts until you can tap your own. It isn’t just efficiency; my hand tapped nuts fit pretty tight and did not show as much backlash as when I had tried to use standard metal nuts. Depends on your nuts, I ‘spose.

Just a thought.
Steve