[diyengineer]

Below is his local ad-posting and emails i received back followed by pictures.
(pictures dont show a lot, but maybe some one could tell me if this would be a decent deal and if the rust would be a monster issue.. bead blast?) I plan on going to take a look at it sunday! I will try and get more photos!. Possibly be a sweet deal with some custom work it could add up to a really nice machine if i could get a 4" z axis out of it (but as long as i can fit a .063" sheet of aluminum-.25" sheet i will be golden!!)
Thanks guys!


"I have a 6' * 12' plotter that came from Boeing. I was planning to raise the rails about 4" and add a Z axis to this machine to turn it into a CNC Router. Unfortunately I have more projects than time and this one is taking up too much space. It has precision rack and pinion rails which would cost you more than the price of this whole machine."

"Here are some pictures of the biggest problem with this unit. It has been stored under cover the entire time I owned it but it was not in a heated space all of the time and there is some rust on the rails which will need to be dealt with. To answer your other questions.
1. What material is the table and machine made out of?
I am not exactly sure but some sort of plastic or fiberglass, it is covered with 1000's of small holes that were used for vacuum to hold down the vinyl. That is the table, of course. The frame is steel and very rigid. If you know anything about vinyl plotters, the concept is to cut through the vinyl and leave the paper backing, this is very tight tolerances.
2. How many rails are there, it looks like the table is in halfs.
The rails themselves are about 2 feet long and numbered to match, they are all mounted on a scraped aluminum rail for flatness. The table is in 2 parts and the end piece is laying on top of the other. This machine was 40' - 60' long when it was in use but I only have the 2 tables as I did not see any reason for the others, my shop is not that big.
3.does it come with any motors, electronics?
All of the drive motors are there. There is an electronics cabinet that came with it and you are more than welcome to it also. As for anything that will work out of the box, don't count on it. My plan was to install servo drives and Mach software. I have one other machine running on Mach now and one more in the works. Great software!
4. How many axis's does it have x,y,z?
It has 2 driven axis's and a plate where the plotter knife used to be mounted. The Y axis ball screw has a huge pitch on it and I was planning on having to replace it but with the torque needed for plasma that may not be necessary. The rust on the screw might be the only concern. Maybe it was someone else that wanted to build a plasma table, I can't remember."

update:
"I can get you the exact dimension tomorrow but I am sure the Z axis is in excess of 2".

"The motors are attached and they are servos. Servos are what I have on my other machines and I have had no problems. I assume that you are talking about connecting the two tables for your third question. It is lined up with guide pins and the bolted together. The pinion rails are numbered to mate in the center. I am 95% sure that the rails I have are numbered to match"


Update 2:
"I am not sure what they weigh but I can pick each piece independently with my Bobcat which is capable of about 4000#. My guess would be 3000# for the main unit and another 1000# for the extension. Because of the length of it I can not pick them up together."

So far its huge and heavy duty steel!! Thoughts opinions?!

[Bartuss1]

a lot of scrap, waste of time

[Al_The_Man]

A bit of overkill if you just want a hobby machine, but if you want a very sturdy professional table you could turn this one into it with some work, this appears to be a very high end table in its day.
If he can move a bit on the price, it would be worth it.
Al.

[diyengineer]

I will go take a peak @ it sunday, and come back with a wealth of information and lots of pictures!! Hopefully those will help me decide. To remove the rust would a simple bead blast and re-oil do? Or would i have to blast them and get them re-plated. It also needs a new coat of paint, that beige is not cool haha!

[Al_The_Man]

To remove the rust would a simple bead blast and re-oil do?

I think I would remove all the rack and rails and run them through a H.S. wire brush first, it may be less invasive than sand blasting.
Al.

[rowbare]

I don't think bead blasting would be good for the rust on the rails etc... It is probably just a bit of surface rust that could be removed by electrolytic rust removal (google it if you aren't familiar with it) or with a good rust removal solution.

bob

[diyengineer]

Attached are all the new pictures i received. It appears to be a TANK and VERY solid. Since i really only want to cut sheet metal on it this might just be a perfect candidate! It just needs new electronics, and a lot of TLC. The pictures below are better than the last! Take a look.

[diyengineer]

I don't think bead blasting would be good for the rust on the rails etc... It is probably just a bit of surface rust that could be removed by electrolytic rust removal (google it if you aren't familiar with it) or with a good rust removal solution.

bob

Wow i looked it up and A LOT of videos on youtube. Citric acid seems to be a awesome approach as well. Yes bead blasting seems like a bad idea now compared to those ways.

[multiplex]

that looks like one hell of a machine if it was only a plotter

soda blasting might be an option too. we have a wet soda blaster here at work we use for mold cleaning that doesn't damage the metal

[diyengineer]

that looks like one hell of a machine if it was only a plotter

soda blasting might be an option too. we have a wet soda blaster here at work we use for mold cleaning that doesn't damage the metal

Yes, Boeing never skimps on anything lol. I was looking at a guy online clean ballscrews using a pvc tube, citric acid, water and a cap. He put the ballscrew in the pvc pipe with the end caps on with the citric acid and capped it off for 24 hours, came back and it was like brand new. That could be a CHEAP DIY way of cleaning the rails, and ball screw along with a few other parts. As far as the table goes, if there is any rust i can just use a abrasive pad and a high speed to get it off. the table though looks to be in mint condition, just old. What would be the best way of going about putting a new coat of paint (anything but beige) on it? Possibly primer directly over the old beige and spray? Also after the rails are cleaned how do i keep them from rusting again? Lots of oil on a regular basis?

[Al_The_Man]

That ball screw is very high lead! and a bit rusty, you may need to repack the nut as the balls are most likely very pitted?
For pre-painting use varsol to or better still some pre-wash-degreaser from an automotive store.
To apply the new paint, a roller makes a better job than brush and is a bit less messy than spray, you can get the smaller ones for the detail.
Tremclad makes a good product in paint.
They have a machinery blue if you want to go darker.
Al.

[diyengineer]

That ball screw is very high lead! and a bit rusty, you may need to repack the nut as the balls are most likely very pitted?
For pre-painting use varsol to or better still some pre-wash-degreaser from an automotive store.
To apply the new paint, a roller makes a better job than brush and is a bit less messy than spray, you can get the smaller ones for the detail.
Tremclad makes a good product in paint.
They have a machinery blue if you want to go darker.
Al.

Highlead ballscrew is good or bad Al? lol

[Al_The_Man]

Probably high lead because it was a plotter, Plasma uses this method also, no side forces so you can afford to go smaller low inertia motor as no unknown side forces as with a router.
What is the purpose of the large gear disc in the 4th photo?
What do the servo motors look like if you have them?
Al.

[diyengineer]

Probably high lead because it was a plotter, Plasma uses this method also, no side forces so you can afford to go smaller low inertia motor as no unknown side forces as with a router.
What is the purpose of the large gear disc in the 4th photo?
What do the servo motors look like if you have them?
Al.

I asked about the LARGE gear disc, and also info/pictures of the servos.
Regarding the high lead ball screw, what does that mean for me then, in regards to milling my aluminum sheet? use bigger stepper/servos? higher lead=takes more power to turn them or the opposite?

Also since its rack and pinion is there one motor on each side moving the gantry? Or one motor drives some kind of gear train that drives the entire gantry equally? I know its a shot in the dark since you cant see the motors but just in general practice i was wondering..

[diyengineer]

That ball screw is very high lead! and a bit rusty, you may need to repack the nut as the balls are most likely very pitted?
For pre-painting use varsol to or better still some pre-wash-degreaser from an automotive store.
To apply the new paint, a roller makes a better job than brush and is a bit less messy than spray, you can get the smaller ones for the detail.
Tremclad makes a good product in paint.
They have a machinery blue if you want to go darker.
Al.

I found the tremclad "rust-oleum" website, thanks for the pointer! It seems like they have it in many spray on colors as well.

As far as the vacuum hold down table goes i wonder if i can get that beast to work? I have shop air, but only a 60 gallon tank.

[RomanLini]

The large gear is the rack pinion drive gear. There appears to be one motor 2.5:1 step up belt, shaft connecting both sides, and each side has one of those large rack gears. If you look it is a very fine tooth gear, even just one damaged tooth there could render the whole axis fubar.

I don't buy the claim that it has been "indoors" that amount of rust etc are typical for something that was bought out of a scrapyard that has been sitting there in the weather for some time... And bought for about $250 for the scrap steel weight value.

It's gonna be tough to say whether any of those bearings or that leadscrew will still be ok after cleaning the rust. The high lead screw won't take much cutting force, probably not suitable for CNC machining and even a few pits in the groove make that screw useless.

I'm with Bartuss sorry, that looks like $250 of scrap steel to me.

[diyengineer]

Its been indoors in a shop. We live near Seattle.. My shop is also unheated and anything that isn't oiled rusts in days, weeks if your really lucky (no salt in the air just rains 24/7). Only way to get around it is to have a heated shop. Tonight i did the citric acid and water test on a 30 year old rusty shovel, it has not even been sitting in the solution for 2 hours and it already looks like NEW without any kind of wire brushing! Its amazing!!! I took a few pictures before i dunked them so ill be sure to post after pictures.

He actually uses a few other of these machines for milling wood, and one as a cnc plasma table. He purchased them from Boeing surplus which WAS a monster unheated dry warehouse.

Overall i just want to cut .063" sheet. which by the size and looks of the thing, looks like it could handle it fine. The size of my sheets are 60"x144" so the table size works perfect. I personally think its a crap shoot, but if for some reason the gantry doesn't work its still a sweet table that i can start a custom machine from. A bolt together 80/20 frame is going to cost me 1500 bucks alone. This is half that price, with a possible chance of it working. If it doesn't work i made out with a 6'x12' table for half the price of a 80/20 bolt together 24"x34" table, that has a 4000 pound steel structure, and was built by one of the best factories in the world. Can i really complain? =)

Side fact: I did work there for a year building the left inboard wings (clad aluminum leading edges) on the 737's. If your ever in the seattle area (north of seattle, Everett) and want to see the largest building in the world (FACT) stop on by. 4.3million square feet & 472 million cubic feet.

Sunday i will take enough pictures and see it in person to make a real judgement call. My brothers Canon EOS 5D MKII will be catpuring this beast in HD. Cross your fingers ppl.

Thanks for the support and honesty, it means a lot!

The large gear is the rack pinion drive gear. There appears to be one motor 2.5:1 step up belt, shaft connecting both sides, and each side has one of those large rack gears. If you look it is a very fine tooth gear, even just one damaged tooth there could render the whole axis fubar.

I don't buy the claim that it has been "indoors" that amount of rust etc are typical for something that was bought out of a scrapyard that has been sitting there in the weather for some time... And bought for about $250 for the scrap steel weight value.

It's gonna be tough to say whether any of those bearings or that leadscrew will still be ok after cleaning the rust. The high lead screw won't take much cutting force, probably not suitable for CNC machining and even a few pits in the groove make that screw useless.

I'm with Bartuss sorry, that looks like $250 of scrap steel to me.

[Al_The_Man]

Also since its rack and pinion is there one motor on each side moving the gantry? Or one motor drives some kind of gear train that drives the entire gantry equally? I know its a shot in the dark since you cant see the motors but just in general practice i was wondering..

There are basically two methods used with these large gantries, you can have two X axis motors, one each side, in this case the controller gears one off the others encoder.
Another method is to use one motor and have an shaft under the table to the other side for the other rack drive.
Also one side is often compliant the other side non-compliant, this avoids the necessity for BOTH sides to be accurately aligned along the full length of the table.
Al.

[diyengineer]

There are basically two methods used with these large gantries, you can have two X axis motors, one each side, in this case the controller gears one off the others encoder.
Another method is to use one motor and have an shaft under the table to the other side for the other rack drive.
Also one side is often compliant the other side non-compliant, this avoids the necessity for BOTH sides to be accurately aligned along the full length of the table.
Al.

"I don't have a picture of the servo but I will check and see if I can get one. The large gear is connected to the pinion for the X axis and meshes with the smaller gears that you see there. My only assumption due to the size of that gear is that the servo that runs the X axis must be a very fast motor."

That's what he said about the black gear.

[Al_The_Man]

4th photo: If the pinion on the extreme RH side is the motor, the black gear offers no reduction? As it drives the same size gear.
It is not clear what the motor pinion is?
Al.