Hotbed flatness, voodoo or scientific method?

It doesn't have to be about "money is no object". It's simply a matter of recognizing compromises that are made in order to keep the cost where you want, then living with the consequences of those compromises. Over the last two years I've probably spent $500 on parts that have been in and taken out of my machine. Once I had it printing I started looking at all the things I thought were wrong with it and started attacking the problems one by one. You can see many of my mistakes here: [mark.rehorst.com] When I started my printer project I had an advantage - my first encounter with a 3D printer was a Makerbot Cupcake- a terrible thing that made obvious the need to have a sturdy frame to build on. One of the few things that haven't changed in my printer is the 8020 frame construction.

A perfectly flat bed plate (and autotramming) does not fix deficiencies in the construction of the machine. If the guide rails sag, or the z axis screws suck, or the frame flexes, or the temperature varies too much, you're going to have problems with prints sticking to the bed and other print quality issues.

Cast aluminum tooling plate is flat enough (I have printed in 50 um layers on my printer and I can print nearly edge to edge) conducts the heat, and is certainly able to withstand more abuse than any glass plate. There is no readily available, lower cost, lower mass, thermally conductive, flatter surface available and it works. It is a solved problem. If the extra moving mass causes a problem for your Y axis motor, you slow the acceleration and reduce jerk. If you don't want to do that you get a bigger motor and/or use a better driver. If you don't want to spend the $30 for a piece of tooling plate, and would prefer to spend $20 and many hours trying other things, that's your choice. But if the $10 price difference is worth the many hours you're going to spend messing around, maybe 3D printing is just too expensive a hobby for you anyway. For me, life is too short to spend it reinventing the wheel. I'd rather use the time to improve my CAD skills, etc.

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So where would we be if money was no object?

You wouldn't be asking things here, you would get a 200,000 commercial printer and asking questions to the company's support department.

The higher your expectations the higher the price tag. Can you drive back and forth to work on a yugo or do you prefer a Rolls Royce?

We all want to have some fun with 3d printing, some people would be able to afford high end printers and will enjoy high quality prints, some like me will have to live with all the issues and limitations of cheap printers and work our way up through little improvements at the time.

My little printer didn't cost me 1300 dollars, at the most it cost me 300 and a week or two worth of cad design. It's my built plate absolutely flat or perfectly level? Most likely not. But since I couldn't afford 1000 dollars worth of materials to achieve that, I invested 9 bucks on a sensor and a simple ABL function of the firmware. Haven't lost a single print to adhesion, don't care what anyone have to say about ABL "it works for me" period, and I can save my money for more important things like a good extruder system and a better and more reliable hotend. I can bet you that out of 10 lost prints 7 or more will be due to those two items and probably 1 Or 2 out of bed flatness.

These problems have all been solved centuries ago by machinists. All you need is a dial indicator.
Squareness is also easy to measure, but more expensive since most squares with <0.001"/ft accuracy costs 200$+.

The biggest problem you will run into is that the printer flexes too much to get a reliable reading. If you measure with enough resolution pretty much everything flops around, especially once you start printing.
Note that although a sloppy machine will be nearly impossible to level, it doesn't need to be perfect since the extruder will be able to push the build plate downwards a bit if things get too close.

If you want to see what the pinnacle of ridiculously high speed positioning looks like, modern pick and place machines get pretty close. The bleeding edge seems to be linear servos and granite. Sometimes you see carbon fiber for the gantry.


I'm actually working on a printer built from surplus linear servos. Obviously it is complete overkill and makes no sense, but I got them cheap and have nothing better to do. I'm going to have the frame waterjet from either granite or Mic6.

[www.everythingbends.com]

My current progress is ahead of the blog, but things have been going slower than anticipated due to work.

You can check squareness by measuring diagonals with a steel ruler- no expensive instruments needed. If opposite diagonals measure the same, the frame is square (or at least the part of it you're measuring).

If you build the frame square and verify it by measuring diagonals, you can align the axes to the frame using metal spacers between the frame and the guide rails and know that they too, will be square to each other. The final test comes when you print a large rectangular block and measure diagonals in each plane.

I wrote a spreadsheet that calculates the error and will tell you which axis and how much correction to apply. You can DL it here: [mark.rehorst.com]
It says X and Y axes but it applies equally to any two axes in the printer.

Interesting topic and something I have recently been battling.

I am using the Mk3 aluminum plate and I can tell you that this is by no means flat.

First thing to consider is that you cant mount the plate in the mill and try to surface mill it flat, it just wont work with such a thin plate. You will need to remove metal from both sides to do this and having a heating element bonded to one side precludes this option.
Also if you clamp down the plate you press it flat while you are machining, release it and the bend returns.

I ended up mounting my plate in my mill with the sides just on two equal thickness pieces of metal so that the plat was suspended from its edges. I then put a steel rule across the plate and looked for light shining from under the rule (indicates where the plate is below the rule). I then used the mill quill to apply pressure downwards on the plate (or if it bent upwards flipped it over and pressed down. After doing this a few times and using the rule check I was able to get the plate straight enough for 3D printing. Before I would get adhesion in the center and nothing at the outer edges, last night I did a print which covered most of the plate and I got adhesion along the entire surface.

For the above method I also found it better to put a round bar across the plate and use the mill to press down on this, this was I applied pressure over the whole lenght. Using this and the outer metal bars I could bend the X and Y independently.

From my observations, anodized aluminium sheet tends to be flatter than plain aluminium. I think that this is because it is assumed that it will not be bent and has a harder temper. Also, sheets that I have bought are typically A4 size (210 X 297mm) rather than as offcuts from a 2000 X 1000mm sheet stored vertically in a wooden rack. In the 7 or 8 sheets of 2mm and 3mm anodized aluminium that I have used I found no error larger than 0.05mm (0.002") across the whole surface.

well I completed step one toward a flatter bed, it is the ghetto way but it is cool to see what kind of variance I am getting, I printed out and installed the components for auto bed leveling and I did a couple prints like this and I have to say even though my bed is not level this is my best looking first layer so far, once I get the bed flatter with new components this thing is going to rock. I can see how a lot of people settle for only auto leveling even with a crappy bed it gets rid of the uneven bed causing filament jams in the extruder which has been my nemesis since I started 3d printing.

[www.youtube.com]

My new M2K heatbed was shaped like a cereal bowl. I use 1/8th inch aluminum plate with 1/8th inch glass. It's enough to flatten the heatbed with clips. Are silicone heatbeds a better option?

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the_digital_dentist

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JamesK
That 1/4" plate sounds nice, but it will add a lot of mass to a moving print bed design. The simplicity of the Prusa layout is very appealing, but I keep finding myself drawn to a core-xy layout with the bed motion confined to Z. Maybe next time.

I was wondering about epoxying some pieces of aluminum U channel to the heat bed to increase flatness and rigidity, but I have my doubts about how the combination would cope with thermal expansion/contraction. My current plan is to have the heat bed track side up with a thin aluminum sheet to act as a heat spreader and glass on top as the print surface. I guess with that layout I could tolerate some warp in the heat bed itself as long as the aluminum and glass stayed fairly flat and there was still adequate heat transfer. Maybe I can bond the aluminum to the bed with a thermally conductive glue?

What are you trying to achieve by combining all this stuff? Putting multiple thin layers of different materials together, each with different expansion and warp behaviors over temperature, is a sure fire way to never get the thing flat. An aluminum plate is simple, inexpensive, and works without any screwing around. My 12" x 12.5" x 1/4" plate cost about $30. Are you going to save $5 and 100 gm by using thinner sheet and a piece of glass, and some mystery adhesive?

Where from for that 30 dollars and for those of us without a DP we would need one with holes pre drilled. Funny that this really flat aluminum is not sold for our beds.

I could not get my bed level as it has two bad areas that I found when I just went to a 3 point leveling on my Prusa I3 rework and that is the front (towards me) with the two screws has a slight .1-.2mm bulge and the far right corner (the side with the 1 screw) drops by .15-.3mm. I used a feeler gauge on all four corners, the middle, and the middle front and the middle back (next to the leveling screw) and found those two bad places. A 3mm aluminum heat spreader + 3mm boro glass did nothing to help either and when I removed the spreader ( just using the boro and the MK2B ) those two spots were exactly the same. So, I cannot print and I just want a way to use this boondoggle of a printer I made back in Feb 2014 with very few hours printing and thousands and thousands of hour freaking with it to no avail.

So, I know 100% I cannot drill straight holes with what I have at hand they are always at an angle so I would take the final chance with some 30 dollar miracle cure if it came with pre drilled holes in the right places,

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

cast aluminum tooling plate

ebay

It's not funny, it's tragic that kit makers don't provide decent parts, especially when they are so readily available, but they have figured out that the average 3D printing hobbyist shopping in the $300 printer market doesn't really know what they are buying. What do you expect for $300? So many people are so focused on price that they ignore the performance hit that comes with the compromises made to achieve that price point. If you were buying a new car, say a Yugo, for $5000, would you expect it to be anywhere close to the comfort, performance, and reliability of a $15k Toyota Camry? Of course not. So what made you think a $300 printer was going to work any better than that Yugo? You paid a Yugo price, you got Yugo performance. That's how 3D printing (and everything else) works.

The bed plate isn't the only place where you got screwed. They probably used bent threaded rods for the Z axis and drive them with 2 motors, and they probably hold the bearings in place with zip-ties. The machine's frame is probably made of cardboard (aka MDF) or laser cut acrylic that is about as rigid as jello.

The holes in the bed plate do not require precision. The plate is only 1/4" (6.35 mm) thick. You can drill them straight enough with your eyes closed using a hand drill. If you drill them at a 45 degree angle to the plate they'll work fine. They are actually oversized so that the bed can tilt freely. The springs underneath push the plate against the screw heads. You measure the locations with a ruler, punch, then drill. I countersunk the holes and used flat head screws so nothing would stand up over the bed to possibly injure the hot-end. Countersinking is optional, but probably helps with stability by putting the plate in contact with the screw head to prevent lateral shifting of the bed around the oversized holes. I hate to be the one to have to tell you, but if this sort of simple mechanical operation is beyond your abilities, 3D printing probably is too.

Countersink bit

By your own accounting, you've spent thousands of hours trying to make a warped/bent bed plate work. Finally, someone comes along and explains why it doesn't work and exactly what you need to fix the problem, but you're unwilling to try it because it costs $30. I don't get it. Someone who wanted your money told you that you could have a magically wonderful 3D printer for $300 and you believed them and handed them $300. I'm not trying to sell you a metal plate. The money doesn't go into my pocket. I'm trying to help you understand the problem and solve it. If you're not interested in the solution, why are you here?

If I offered to pay you $30 for "thousands of hours" of work, you'd tell me I'm nuts and walk away. But you took that job when you bought that printer. You're $30 richer now after having spent thousands of hours trying to get your printer to work. Before you spend thousands more hours trying to make a warped piece of metal and glass flat by adjusting the leveling screws (hint: the leveling screws can't make warped materials flat, no matter how much you turn them), why not spend $30 for an actually flat plate and install it into the machine in just a couple hours? Right now you have a $300 pile of junk. Maybe, if you get a decent bed plate, you'll end up with a $330 printer that works. Then you can move on to reversing all the other compromises the kit maker made.

If $30 for the plate is too expensive, 3D printing is too expensive too. You'll pay that much for about 1 kg of filament.

I purchased a test piece of 1/8" flat bar (non hardened) and my holes were off and slanted (I used a mechanical hand drill as I have more control but just can't do straight it ends up about 30-45°). So, I need a way to make straight holes for sure just like cutting with a hacksaw I must use a miter box.

Why are you so defensive? I asked you for your help so it surely means I already know the issues you speak of though not all of them pertain to my issues they are still very valid (my printer was not a kit I selfsourced all of it). Everything is stainless steel or Aluminum on this printer. The frame is 1/4" (6.35mm) as is the frog plate but they did come bent from a company who no longer is in business as the owner died. I have no idea if it was UPS (probably) or was shipped that way but I was not going to bother the departed man's wife right after he died. So, I made the frame straight with support beams but the frog plate has always sucked. Matter of fact I have use the stainless screws so much trying to level it that one hole finally gave out and is officially stripped. Was already wobbly so I knew it was coming.

So, this printer was far far from 300 dollars. The 8mm rods are from Misumi with a double layer of chrome and the M5 all threaded rods are SS I purchased and yes, then warped on me but if I can get this printer to print I am moving over to TR8x2.

The deal is if this is to be used to hold those bearings I really do not have a template as Prusa, grrrrr, decided to stupidly design the Frog plate with 20mm ctc holes for the bearings not 24mm which is what I need as I am done with printed brackets, tie wraps, zip ties, etc... and was going to go to 3 SCV8UU but not on this frog plate I am not. Just need a template which shouldn't be too hard to find or make then I just use the center punch and try to drill the holes out but for 1/4in tempered Aluminum (damn all of the frames for the i3 are not tempered so sucks) I will not be using my manual hand drill that is for sure.

Oh, a truth in advertising would be that to your door the plate is almost 40 dollars and if people are grumpling at 30 they will bitch at 40.

edit: Another thing that 12x12 *MUST* be cut as the frame for the I3 is only 260mm wide which is 10.2362 inches (actual frog plate is 220mm which 9inches square would work) so drilled and cut is required. Might be able to do the drilling but the cutting for such a wide piece? No.

Would this work? [www.midweststeelsupply.com] 1/4" 8.6875"x8.6875" costs $11.59 and ups second day air (I hate UPS so the less time they have to bend it the better) is $23.72 so around 35 dollars.

Edited 5 time(s). Last edit at 06/22/2015 02:00AM by Dark Alchemist.

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Would this work? [www.midweststeelsupply.com]

Good find - looks perfect! I didn't check the exact size you'd need for the bed, but I'm guessing you checked that already.

Yes, that plate should work.
IRIC, I picked my plate up at the local Speedy Metals two years ago for $30. Yes, unfortunately, prices rise and companies do charge for shipping. I don't understand why you're complaining about the cost of the plate. You just spent extra to get 2nd day air delivery. Someone who does that doesn't seem to actually be too concerned about cost. You don't have to worry, UPS won't be able to bend that 1/4" plate if they try.

Cast tooling plate isn't "tempered" or hardened. Casting is the method by which the plate is manufactured. Here's some verbiage from one manufacturer:

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Mic 6 Aluminum
Stability is the defining characteristic of MIC 6® Aluminum. Only MIC 6® is cast to near net thickness with a stress-relieved, granular structure to virtually eliminate distortion from machining and end use temperature fluctuations.

The manufacturing of the MIC 6® is the most advanced process in the cast plate industry. It promotes consistancy between plates and reduces the risk of disrupting material stability by entrapped stress. The optimium in molten metal cleanliness has been achieved by the continuous application of SNIF degassing and impurity removal technology to every MIC 6® plate that is cast.

MIC 6® allows for down-stream processing with precise control of tolerences and dimensionality. MIC 6® is a free cutting aluminum alloy that produces small, uniform chips in a variety of high speed operations.

MIC 6® customers can perform extensive machining routines involving metal removal with minimal risk of distortion, often exceeding the product accuracy requirements of the most demanding uses.

The stuff about eliminating distortion from end use temperature fluctuations is one of the things that makes this stuff great for 3D printer beds. It's flat, thermally conductive, easily cut/drilled, and maintains its shape with variations in temperature. What more do you need?

Of course, if a 12 x 12 plate won't fit in your printer you either have to find a smaller plate (as you did- that wasn't so hard, was it?) or cut it to fit. You can cut aluminum plate easily with a jigsaw, bandsaw, or a table saw with a carbide blade.

I appreciate that you spent more than $300 on your machine. You bought a bunch of more expensive parts to build an i3 printer than the $300 kits normally come with. Unfortunately, the materials aren't the whole problem- the design is poor and using more expensive materials doesn't fix the design problems. Mild steel, stainless steel, or diamonds doesn't change the fact that threaded rods are bent and have no place in a precision mechanism. 8mm end supported guide rails flex equally whether they are surface hardened or not. Using two motors to drive the Z axis screws means you'll be realigning the X axis frequently.

As my grandmother in Tennessee used to say, "you can't make a silk purse out of a sow's ear".

Not just in this forum but also in other places I saw the stories of printbeds not being flat at all.
From some of my postings you might already know that I am printing on and old Prusa but it came with an acrylic print bed - worst thing ever....
So I thought it is time to share how I was able to level my printbed perfectly (well at least as far as can measure) at next to no cost :

I rejected and sent back some heatbeds, the normal ones as well as the thick aluminium ones - because their claim of providing an even surface was crap...
Trying various types of glass I found one that is almost perfectly flat already and still qualifies for the use on heated print beds:
The glass used on flatbed scanners or copy machines!
Window glass, borosilicate - you name it and they all look flat until you start printing on them.
But with glass print beds there is a secret that makes them flat and I use it on my scanner glass as well.
You know these four sided diamond sharpening blocks for knifes and tools?
They are perfect level a glass print bed down to really tight tolerances.
As you would sand down a flat surface with sand paper you do the same with the 300 grid side of the diamond block - a normal diamond sharpening plate will do fine too.
The glass turns dull where it is sanded and stays clear in the areas that are still lower, so you effectively remove all bumps first.
With circular motions and a bit of water it does not take much to get to the state where there are only a few patches of clear glass left.
Here I change to the 400 grid side and continue the "sanding".
Once the surface is evenly milky you can be almost sure there is enough flatness to start with a 0.1mm layer thickness - if the bed is levelled properly.

Upsides of the method:
The print surface will be almost perfectly even.
Using plastic primer and ABS juice you can print ABS on a cold glass plate.
PLA often sticks to the rough surface directly it the temp for the fisrt layer is set a bit higher.
Cleaning is easy as a sharp knifes removes most residues and the rest is done with methylated sprits or acetone.


Downsides:
Nothing is perfect, so getting kapton tape to stick is a pain in the butt - don't try as you will waste the tape.
PLA can still be a pain as not always sticking is as easy as it should - if in doubt a layer of ABS juice or plastic primer does the trick.
ABS with sharp corners on low profiles still tend to lift off a bit on a cold bed, on a hot bed it should be fine though.
Nylon does not stick to the surface, even with plastic primer it is quite hard to make it stick. I compensate by using two printbeds.
For the nylon prints I first print a thin layer of ABS onto the surface treated with ABS juice. Does not always work as planned but in most cases it does.

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the_digital_dentist
Yes, that plate should work.
IRIC, I picked my plate up at the local Speedy Metals two years ago for $30. Yes, unfortunately, prices rise and companies do charge for shipping. I don't understand why you're complaining about the cost of the plate. You just spent extra to get 2nd day air delivery. Someone who does that doesn't seem to actually be too concerned about cost. You don't have to worry, UPS won't be able to bend that 1/4" plate if they try.

Cast tooling plate isn't "tempered" or hardened. Casting is the method by which the plate is manufactured. Here's some verbiage from one manufacturer:

Quote

Mic 6 Aluminum
Stability is the defining characteristic of MIC 6® Aluminum. Only MIC 6® is cast to near net thickness with a stress-relieved, granular structure to virtually eliminate distortion from machining and end use temperature fluctuations.

The manufacturing of the MIC 6® is the most advanced process in the cast plate industry. It promotes consistancy between plates and reduces the risk of disrupting material stability by entrapped stress. The optimium in molten metal cleanliness has been achieved by the continuous application of SNIF degassing and impurity removal technology to every MIC 6® plate that is cast.

MIC 6® allows for down-stream processing with precise control of tolerences and dimensionality. MIC 6® is a free cutting aluminum alloy that produces small, uniform chips in a variety of high speed operations.

MIC 6® customers can perform extensive machining routines involving metal removal with minimal risk of distortion, often exceeding the product accuracy requirements of the most demanding uses.

The stuff about eliminating distortion from end use temperature fluctuations is one of the things that makes this stuff great for 3D printer beds. It's flat, thermally conductive, easily cut/drilled, and maintains its shape with variations in temperature. What more do you need?

Of course, if a 12 x 12 plate won't fit in your printer you either have to find a smaller plate (as you did- that wasn't so hard, was it?) or cut it to fit. You can cut aluminum plate easily with a jigsaw, bandsaw, or a table saw with a carbide blade.

I appreciate that you spent more than $300 on your machine. You bought a bunch of more expensive parts to build an i3 printer than the $300 kits normally come with. Unfortunately, the materials aren't the whole problem- the design is poor and using more expensive materials doesn't fix the design problems. Mild steel, stainless steel, or diamonds doesn't change the fact that threaded rods are bent and have no place in a precision mechanism. 8mm end supported guide rails flex equally whether they are surface hardened or not. Using two motors to drive the Z axis screws means you'll be realigning the X axis frequently.

As my grandmother in Tennessee used to say, "you can't make a silk purse out of a sow's ear".

Who is complaining? I never even knew this existed for this cheap. I am glad I found my size that is as exact as to the third place so I do not need to cut it (eliminates a problem). I will just do ground shipping because they are so close to me it is 3 day shipping. Yes, the Prusa i3 rework is a turd as far as design goes but once I can start printing I will fix some of that with those TR8x2 for Z and get on a better Z endstop (I wish I had a repeatable Z endstop but these micro switches are far from repeatable).

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

My initial impressions of the optical endstops are very positive, although I haven't made a serious attempt to measure repeatability yet. The lack of physical contact makes me feel fairly confident that the things should remain consistent over time.

I was using a microswitch for the Z endstop and it worked fine. I recently switched to an optical endstop to see if it was any better.

If you use a lever on the microswitch I think you'll have problems with precision- the combo of the lever's springiness with the microswitch's internal springs makes for unpredictable switching. If you directly push on the button on the switch it works well enough.

The main difference between an optical and microswitch endstop is that the opto interruptor has no hysteresis. It switches when the beam is blocked/opened. There's no adjusting it until it clicks then backing off the screw "a little" to compensate for the hysteresis. Also, the opto endstop doesn't click when it switches, so you need an LED or other means to monitor the switching. My smoothieboard displays the status of the endstops on the LCD display so that's how I adjusted the opto endstop.

I agree JamesK though light can affect them. Magnetic reed switches have no contact but are not all that repeatable.

Oh, for the metal here is the spec sheet and it is better than the Alcoa Mic-6. [www.vistametals.com]

6.35mm to 101.6mm (1/4” to 4.00") has a flatness tolerance of +/- 0.127mm (+/- .005”) which falls within my 0.26mm first layer height so is perfect.

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Midwest Steel & Aluminum
We are domestically partnered with Vista Metals out of Fontana CA, our Vista Metals ATP-5™ cast aluminum plate can be produced in custom widths and lengths with a very short lead-time.

So, I am asking how much would that plate be for exactly 220mmx220mm @ 6.35mm (1/4") if it is more I will simply get the imperial which is so close to 220mm sq. it really wouldn't matter.

Edited 1 time(s). Last edit at 06/22/2015 10:44AM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

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the_digital_dentist
I was using a microswitch for the Z endstop and it worked fine. I recently switched to an optical endstop to see if it was any better.

If you use a lever on the microswitch I think you'll have problems with precision- the combo of the lever's springiness with the microswitch's internal springs makes for unpredictable switching. If you directly push on the button on the switch it works well enough.

The main difference between an optical and microswitch endstop is that the opto interruptor has no hysteresis. It switches when the beam is blocked/opened. There's no adjusting it until it clicks then backing off the screw "a little" to compensate for the hysteresis. Also, the opto endstop doesn't click when it switches, so you need an LED or other means to monitor the switching. My smoothieboard displays the status of the endstops on the LCD display so that's how I adjusted the opto endstop.

When I used a mechanical switch (exact same one used in endstops) without the paddle for my ABL it was repeatable to exactly two decimal places which is pretty tight but is the optical any tighter?

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Five business days for it to arrive to me so I will order it on after hours on Wed so it doesn't have a chance to sit over a weekend when UPS does 99% of their damage to me (or theft). Very nice people I spoke to as well AND theirs *IS* flatter and straighter than Alcoa's MIC-6 (I could tell that by the spec pdf).

Getting the proper sized (length) M3 will be a tad bit of a chore but eBay can handle that.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Note that tooling plate flatness tolerances are across the entire sheet and are absolute worst case numbers (as in you return the sheet if it is out). A small piece is going to be better than 0.001" regardless of manufacturer.

Tighter tolerance then from this manufacturer than Alcoa but the hard part is how do I measure it? Not worried about it from them worried about UPS, who I do believe bent my 1/4in aluminum frame and frog plate last year, bending it as UPS doesn't give a squat about anything anymore. They said they use a cardboard box and the tooling plate does have a thin plastic sheet on it you can remove as it is just for shipping purposes. Should I remove that plastic before I drill or leave it on and drill through it into the plate?

Edited 1 time(s). Last edit at 06/22/2015 05:03PM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Simplest way to check if something is flat is to put it on a surface plate and see if it rocks. You can measure the flatness of a piece by poking around with a feeler gauge, or sweeping with an indicator. Using a feeler gauge is easier but will provide less information.

To perform any of these tests you need an accurate flat surface to use as a reference. I wouldn't trust glass or a counter-top to verify tooling plate.

Drill with the plastic on to keep the surface nice.

I don't own one of those 100-300 dollar flat stones and I do have a DTI but not a stand and I have yet to see a stand that will sweep so what would I use to do that? Also, testing with the plastic on would not be a true indicator I think.

Edited 1 time(s). Last edit at 06/22/2015 06:26PM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Use the edge of a steel ruler- not a wood ruler with a metal strip, but a ruler made of steel. Stand the edge against the surface. If the surface of the plate isn't flat, gaps will be obvious.

Have a brand? Know why I am asking this? I went to Sears and was going to buy one for this purpose and I laid the ruler on its edge against another ruler, and even a flat level, and there was gaps. I was shocked to say the least and put it back on the shelf. :/

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

The cheapest straight reference would probably be a machinists square. It is likely within a thou or two and you will probably want a good square anyways. Rulers aren't really designed to be flat in the thou range, generally that kind of thing is called a straightedge and has no markings.

If UPS bends the plate it will probably be obvious. You can press it against a mirror and see if it rocks for peace of mind.

Aye, use the bathroom mirror and see if it rocks on either side. Would that plastic make a difference? Don't want to drill it if UPS screws it up (trust me I have so many horror stories with them over the last two years they need to go away or be what they were 15-20+ years ago).

I have heard of these machinists squares so I will go look and see what would costs as I will run into other things I need to be sure are flat. (edit: I just looked and I have seen those before and never knew what they were called. Used a helluva lot in the CNC mill/lathe/router world.).

Edited 1 time(s). Last edit at 06/22/2015 07:29PM by Dark Alchemist.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.

Bending a small piece of 1/4" plate is quite difficult. I think you should be ok, even with UPS involved.

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JamesK
Bending a small piece of 1/4" plate is quite difficult. I think you should be ok, even with UPS involved.

No, it really is pretty easy with how UPS treats their parcels now. Fact is my frame and my frog were both bent by them.

I was just thinking and wondering where will this plate go? It can't be a replacement for the Frog since the hpb has to go underneath.

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I await Skynet and my last vision will be of a RepRap self replicating the robots that is destroying the human race.