Things I wish they'd told me

[phil@philsfoils.com]

After first setting up my Shopbot about 18 months ago, I'd meant to add a message on lessons learned. Now that I've just disassembled and reassembled in a new location, its all fresh in my mind again.

1. Footprint. Its bigger than they say it is! If locating into a tight spot, allow a minimum of 7.5" on either side of the X rails (for the depth of the stepper motors) and 8" behind the end of the table supports (for the Z stepper motor & Z gantry). For a wood table, the table itself is 10' 4" long, not 10', by the time you add the two tie rods that hold the X rails together.

2. Wiring. If you faithfully follow the procedure in the book, you'll bundle the stepper wires together and zip tie them to the wand. Then you find out that it would have been best to add the router power wiring at the same time. Then when you start adding your optional z-zero plate and proximaty switches, once again, you have to zip them onto the wiring bundle. For a cleaner installation, bundle ALL wires and run them together.

3. Plywood tables. I'd read here about building the wood table out of plywood (dimensional stability). Turned out well. I laminated together two sheets of 3/4" ply to get the right width. Two tips: use the pre-cut edges of the sheet for the tops of your rails. Perfectly straight and no shims required when bolting the X rails on. Also, pre-drill all bolt locations oversize (for the X rail hardware) and pot with epoxy, then redrill once hardenened. End grain plywood doesn't like lagbolts going into it...

4. Concrete block legs. Again, I'd read here about using concrete block legs, but didn't use them for the initial installation (I knew I'd be moving out after a year). Have done this in the new shop, and its much more stable. I poured sacrete down the center of the cinder blocks (stacked 4 high), with a 3/4" x 36" threaded rod inserted in each one. I put a plywood plate on each corner of the table, and bolted this down to the threaded rod. With nuts over & under the plate, adjusting the 4 corners of the table to be dead level is as easy as turning the nuts.

Feel free to add to this list.
Phil
www.philsfoils.com (http://www.philsfoils.com)

[m. holm (Unregistered Guest)]

Hey Phil,

How about a photo series of your table assembly?

[phil@philsfoils.com]

Well, its all together again, and looks pretty much like most other ShopBots, with the possible exception of the concrete block legs. Time's a bit short with the move, so sorry, no pictures.

[dvanr]

If your considering building the steel table from scratch ( and if you have not done a lot of steel work , info here may be useful) .

The drawing and assembly instruction that you can download are a bit sparse on info .

What I have found out. Working on my own.

You need a big drill, I started with a bench top pedestal drill, it stalled when breaking out the backs of the 5/8th holes, under powered at a 1/4hp. The drill I have now is a full size pedestal , 1hp motor, morise taper, 16 speeds, Low speed 200 rpm for the 5/8ths morise taper bit. Use cutting fluid. The bit lasts a lot longer.

You'll need a sturdy support that is adjustable for the long pieces. Sturdy enough to safely support 60kg.

One idea suggested is make drill templates with drill bushings. You need to still lay out the length spacing but locating and getting the correct distance from the edge becomes a lot easier.

You'll need an angle grinder and access to welding gear or someone who welds. See the end plates and nuts for the legs.

Protective gear, no runners , stubbing your toe on the end of a C channel hurts!! Wear good leather gloves , metal splinters are a distraction you don't need. And of course safety glasses and faceshield depending on what your doing.

And some patience. There are 130 holes to drill, I made pilot holes so that makes 260 iterations. Don't forget your going through 1/4" (5-6mm) of steel.

DvanR

Measure twice, drill once ( advice I wish I had remembered)

[dvanr]

I am at the point where finishing the steel table needs to be done.

Any experiences people would like to share?

Metalhammer, Hammerite, 1 part or 2 part epoxy paint recommendations? Metal preparation?

Still interested in finding out what the closest pantone number is for Shopbot blue.

DvanR

[gerald_d]

Metal preparation......

De-burr all sharp edges with a slight chamfer or radius. The edges must feel safe ("soft") to an un-gloved hand. You cannot build correct thickness paint layers on a sharp edge - it is a weak spot in your whole paint system.

De-rust. Remove all loose rust with a wire-brush mounted in an angle-grinder.

De-grease. Cannot overstress this point. Your new steel may look as if it is free of grease, but it isn't. De-greasing does not mean to wipe it down with a solvent rag - this is not enough. We use a kerosene with an emulsifier additive called Tekprol (http://www.engenchemicals.com/content/chemicals/msds/Tekprol%20131.htm). We wet everything with Tekprol and then flush it off with a water hose - the oiliness turns milky white and one keeps on flushing until the water runs clear. This stuff was sometimes sold as auto engine cleaner, or painter's brush cleaner.

Our standard first layer of paint is a self-etch primer. A slightly acidic paint that "bites" into the surface rust. (after our degreasing, we can see a rust tinge color in less than half an hour - slight surface rust is a good "rough" surface for the paint to adhere into)

[gerald_d]

Oh, I forgot something...

Before de-rusting, use solvent to remove all markings done by a permanent marker. These things have a bad habit of bleeding through a lot of paint systems.

And FYI, the correct drilling speed for a 5/8" drill into steel is around 300 to 600 rpm - not faster. Very few hand-portable drills can turn that slowly, and if they can, they have enough torque to break your wrist!

[dvanr]

Thanks Gerald,

You just saved me a heap of headaches. The paintstore guy never even mentioned engine degreaser.

DvanR

[Brady Watson]

Gerald & Dick,
I have to step in here on the degreasing. Not that I am a die-hard environmentalist...but where is the runoff of the degreaser going to go?

The widely accepted method of degreasing steel is to either have your metal supplier run the pieces through their sandblaster and immediately bring them home to prevent rusting AND/OR wipe the pieces down with acetone.

Acetone will emulsify the grease, prepare it for welding and evaporate without leaving a nasty mess in the yard or your shop. You can also use denatured alcohol.

All of the degreasers (engine cleaner included) are just plain nasty. They are either caustic or toxic and will wind up in the (your) water supply.

-Brady

[stickman]

Hey Guys!

Degrease with DAWN dishsoap.... then air dry with an airhose.... we used to clean five gallon buckets on the ranch with Dawn... it breaks down the oils and greases...

Jay

[gerald_d]

Brady, ever thought of where your acetone vapour is going? (You need a lot of acetone to dissolve grease sufficiently to evaporate - normally one goes sparingly on the acetone and an invisible layer of grease remains behind)

Rest assured that we are aware of this product's toxicity (very low) and the steps necessary to to keep it out of the ground. ....where the hydrocarbons come from in the first place, not out of the sky.

[pierrewessels@hotmail.com]

I built a steel table about 1.5 years ago and encountered alot of what has been mentioned here. I took my table parts to a local powder coater and had the works done in gloss white. At first thought white may seem like the worst color but it actually doesn't show any scratches from "the plastic end of the shopvac" from cleaning. It quite possibly looks better than the all blue shopbot factory colors. The cost to get it done was about $80.00 Canadian. Every time I have tried to post pics it does not work. If anyone wants to post the pics for me I would be happy to email them.
Pierre

[bleeth]

I cleaned up steel parts post drilling with naval jelly and then painted with good old rust-o-leum in a can. Just had to wait long enough for it to really cure before final assembly. Can't say it's perfect but it does the job and looks as good as any other equipment in my shop (except my new Lariat)

Dave

[kivimagi]

Does anyone know the specific paint color, for shopbot blue?(I'm slightly color blind, so I don't trust myself to match)

[brian]

Ryan,
Not sure that this is a huge help but, the guys we get to powder coat the machine use a color RAL 5021 with a ratio 49/42390. These are just a lot of confusing numbers to myself, but to the trained eye of a paintsman, they mean something. You can also get pretty close with rustolium's Colbalt Blue.

Brian

[gerald_d]

Hi Brian, five years at ShopBot and this is your first post - WELCOME!

[kivimagi]

In general, is powder coating an expensive process, or relatively cheap. Did anyone have this done to the steel table they made themselves?

Regards,

[kivimagi]

I just had my table powdercoated. It was $175.00, not sure if that is expensive or not, but I thought it was reasonable.

I chose to go with a black finish. Partly cause I thought black/blue would look better than two shades of blue.(If it wasn't exactly the same)

[dvanr]

I have to put off ordering the BOT parts for a few more weeks. In the mean time I thought I would tackle getting the adapter plate for the router made. The PC router spec'd is not locally available so I settled on one designed by an Aussie company called Triton. (2400watt, 230vac, 8,000-20,000rpm variable speed) more router info (http://www.triton.net.au/products/router_2.html)


3300

Looking at posted pics of various mods in the forum. I'm getting that sinking feeling that the router is too wide.

11.75" or 300mm from the handle ends. The body is one piece cast aluminium , about all I can remove with out using a hacksaw are the plastic bits , that may only gain about 5mm.

Somebody please enlighten me as to what the clearance is between the rails of the PRT96 Y car.

DvanR

[gerald_d]

Pictures 18 (http://www.talkshopbot.com/forum/messages/2/4113.jpg) & 22 (http://www.talkshopbot.com/forum/messages/2/4117.jpg) at the bottom of this page (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=2&post=15264#POST15264) could put your mind at rest. The gap between the unistruts of our y-car is only 210mm, but our router never lifts that high. You could run into a problem if you mount your z-axis higher up. From the bottom of the unistruts to our table top is about 305mm (our table top is currently 95mm below the bottom of the angle iron x-rails.)

[dvanr]

One more piece to the bracket puzzle required

Just need to know what the width of the mounting back plate has to be to clear the V rollers for the Z axis? (and probably the length as well)


DvanR

[gerald_d]

Dick, was my previous post of any use to you? Do you want me to go and measure again?

[dvanr]

Hi Gerald,

The info you provided was of use. ( If I understood it correct.) What I need now is some more info.

A picture is worth a thousand words...in any language ...even Afrikaans.




3301

(photo credit Gerald 2004)

The foot the router I have, is going to be wider then the Z mounting plate. Since I am using the posts that router plunges on. The intention is to split the tube on the end that inserts into the router and draw a slightly wider plug down through the tube to expand the tube to lock the router down and motionless on the bracket.

thanks for the help

Dvanr

[gerald_d]

Width between the rollers is: 98mm
Our plate width: 85mm
Our plate height: 112mm

We use a lot of g-clamps for holding stuff down, and a wide plate under the post positions could foul with the g-clamps. That is why we went for a narrower position. (We even cut off the two flat bar tabs you see in the pic above). Our 6mm die-grinder really spoiled us with its deep reach - we have to be a lot more careful with the new beast.

[gerald_d]

In this pic (http://www.talkshopbot.com/forum/messages/2/4251.jpg) you might notice that we shortened the vertical posts on the bracket, plus squeezed in an air deflector plate between the router and the bracket. (Our die-grinder doesn't stir up any dust either - another area where it spoiled us)

[dvanr]

I'm a bit annoyed, I just discovered that the toprail that the x-rail bolts to must not be wider than 1.92" in order for the rack and stop to be mounted properly.

Being in Australia and having access to channel steel of the dimensions 150 X 75 mm only ( went with the large dimension as my important one) I now have a minor problem. Remove 1" of steel 4mm thick 3.2 meters in length twice. S...tuff happens as they say.

It would be extremely helpful on Shopbots part if they would start a thread that they can only post too called Technical Bulletins. This would announce known bugs, solutions and workarounds as well as news like new PRT drawings posted, etc.

Gerald, your logic on using rectangular tube steel looks better all the time.

DvanR

[gerald_d]

Dick, this is probably not a good time to remind you of this post (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=7&post=14494#POST14494), and many similar.

Don't think of using a cutting torch - that distorts the channel too much. Grinding, with a cutting disc will give the least distortion. For this type of job, I mount a 3mm thick cutting disc in a circular saw. My guess is about 2 discs and 30 minutes labour. We can also get 1mm thick grinding discs here - that would be even better (less heat/distortion).

[dvanr]

No it isn't , but your right it was discussed.

At that point I did not catch the importance of the 2" dimension. ( I'm annoyed at myself more than anything for missing the detail)

That is why a thread with Tech Bulletins would be helpful. Pretty well all the equipment manufacturers I deal with use them , especially if the equipment is evolving. They highlight important details.

I'm going the 1mm disc and hand grinder route and as fast as possible , I've got Shopbot parts to assemble.

By the way for any Aussies reading in, getting the Bot through customs here in Aus was straight forward. No duty charged on CNC parts , just the usual GST and about $250 for cartage and documentation fees for a local Sydney delivery

DvanR

[gerald_d]

The 1mm discs here are meant for stainless steel, and the term INOX gets used. We can only get them in small diameters (115mm) and they are double the price of the thicker discs. But they are beautiful discs to work with - like a hot knife through butter. Maybe 5 of the small discs will do your job - don't be shy to buy more, they are always useful. We use the Pferd brand, and you might even find Pferd in your local telephone directory.

[paco]

How about shortening the distance between the rail sides...?

[slendon]

Hi Dick,

I had the same problem as you...In the end I used 115mm dia. thin 1mm disks to cut the steel, and from memory I used nearly 20 of the disks..A really messy noisy job that took at least an hour and a half per length. Cleaned up the cut with a hand held router running against a straight edge, cost me one bit, but got a nice clean edge.

Good Luck
Steve

[gerald_d]

Steve, you must have been more than 4mm thick to use up 20 discs. But, thinking of it now, Dick may have under-estimated that thickness - a 6x3 channel probably has a flange at least 8mm thick.

Paco, that reduces the y-travel by about 50mm.

[paco]

Just from table frame... without changing the rails holes spec. from the "plans"; leaving the outside/exterior lenght the same as need to be... this should only reduce the interior total clearance between the rail sides/C-channel... just an adaptation to the table/frame...

[gerald_d]

It also pushes the legs nearer to each other in the y-direction, and the router must still fit between the tops of the legs.

[paco]

Well OK... may depends on one setup but I have 2.5" room on mine so this mean 0.5" clear on a standard table/frame with a 49" wide spoilboard...

[slendon]

Hi,

The steel channel I used was 68 x 160 and the thickness of the steel to be cut off is indeed, as Gerald points out, between 8 and 9mms, hence the number of discs used, if, which is likely, the same section is used for the table legs, I would recomend reducing the 68mm dimension to allow for clearance of the dust skirt. I didn't do this and every time I set zero off the prox switch I have to raise the z height to avoid the dust skirt hitting the leg......

Steve

[paco]

That's what i like about my table design/setup (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=7&post=15724#POST15724)!!!
...no legs in betwwen the rails sides; totaly clear; all the room available!!! My setup is a weld one but I believe this can be bolt built with a 3/8" to 1/2" plate at the legs to rails sides assembly...