Spider Conversion (from 3 to 4 Point Leveling)

[sthone]

I've been slowly upgrading all of my M2's to the latest Rev E version and this is a quick tutorial on how I converted the old style 3 point spider to the newer 4 point that the Rev. E has. First the Disclaimer........ I make no guarantees or warranties as to the accuracy or completeness of, or results to be obtained from accessing and using the Information herein.

I first started by removing the print surface and flipping the heat bed plate off toward the back of the printer. (not shown) There's no need to unhook it just be careful not to stress the wires. Raise the platform and remove the (3) M3 x 12mm screws that are holding the Spider to the Mounting Plate. (You can set the screws, springs, and spacers aside as they will no longer be used.) Next remove the rubber corners so you have a bare spider to work with.

Next you need to mark the location of the new leveling screws in the corner of each pad. With a pair of calipers I measured .4135 (10.50mm) from the outer side of each pad and mark a line. I then measure the same distance from the outer perpendicular side of each block and mark another line (you should have a plus at this point in between the two corner mounting holes.)

Then using a punch (or a nail) punch a mark in the center of the plus you made. (This little divot will keep the drill bit centered when you go to drill the hole.)

Next screw on a corner just to double check that your mark is in the correct location. (I am using Jim's Corners.) The mark should be right in the corner as shown.

The next step is to drill a hole through each pad of the spider. I highly recommend using a drill press for this. This hole will be tapped so you need to pick a bit that matches your tap. I chose to use 3mm hardware for this project so I used a #39 Bit. (NOTE - The standard Rev. E Leveing screws are larger than 3mm, but I'm not exactly sure what size they are.)

[sthone]

Next you will be marking the location of the locking setscrews for the leveling screws. Measuring from the front of each pad as shown first mark a line on the side of the spider pad using the same .4135 (10.50mm) measurement. (You can get away with using a calipers but its a little harder because of the chamfered edge so I used a height gauge.)

Next mark another line on the side of the spider perpendicular to the last line at half the thickness of your spider forming another plus. Go ahead and punch these marks like you did for the level screw holes.

You will need to drill these holes to intersect the leveling screw holes you drilled before. This can be a little trickier depending on the size of your drill press but I made it work on a table top size press.

Next make sure both holes are clear of shavings. I blew them out with some brake clean and ran the drill bit back through them by hand.

Next you will need to tap all (8) holes you made. Again I used 3mm hardware for everything so all my holes as tapped with the same tap. (Aluminum is fairly easy to tap but to keep the tap from breaking use plenty of oil on the tap and turn it one full turn in and then one half a turn out and repeat until the hole a fully tapped.)

[sthone]

This is the hardware I used... I chose thumb screws over setscrews for the leveling screws because it's easier than trying to find the back side screws with an Allen wrench during the leveling process.

Available from McmasterCarr[/u]
Plastic Head Thumb Screw Knurled Head, M3 Thread, 0.5mm Pitch, 12mm Long - 96016A054
18-8 Stainless Steel Extended Point Set Screw M3 x 0.5 Thread, 6mm Long - 92775A106
(You can get nylon tipped setscrews so they will not damage the leveling screws but they are more $$$ so I just stuck a piece of filament in the locking hole first to act as a buffer.)

Just screw in the thumb screw in from the bottom, drop a piece of filament in the locking hole, followed by a setscrew. (Do not tighten them yet.)

Next you will be remounting the spider back on the mounting plate. (I used 3/16" x 1/2" aluminum spacers to replace the springs and nylon spacers.)

Also available from McmasterCarr
Aluminum Unthreaded Spacer 1/2" OD, 3/16" Length, for Number 6 Screw Size - 92510A701

Reattch the spider with M3 x 14mm Screws.

[sthone]

Attach your corner brackets and build plate hold downs. (I use a Mic-6 Plate so I used M3 x 25mm screws for the hold downs)

You have to trim back the corners on the underside of your Heat Bed element just enough so the screw rides on the metal plate. (BE VERY CAREFUL NOT TOO CUT BACK TO FAR OR YOU WILL DAMAGE IT!!!!!)

Place the heat bed plate and build surface back on the spider and you are good to go. (Make sure the hold downs are parallel to the sides of the build plate or the right side rear one will hit the nut on the underside of the top of the printer.)

You can now run your leveling process and easily adjust your screws.... just remember to lock the locking setscrews when you are done.

For the full Rev E. experience you need to move your end stop button to the bottom of the printer and reflash your firmware with the correct version which I'm not going to get into at this point because I'm still not sure which version to run myself. (I'm still using the beta version we received during testing.)

[Jules]

Whoa! Great writeup again Steve!

[3dPrintingMD]

That's some nice work right there. I personally have an issue with my 4 point leveling system as it seems that my HBP is too small and barely makes solid contact on all 4 posts evenly, thus adding to leveling issues when things shift around.

Gives me some ideas that could correct it. I wonder if anyone else has this same issue or...?

[sthone]

Houston we have a problem.....

I think I may have been a little premature with this tutorial.... My first printer was circa 2014 and the conversion I just did I used the spare spider off of that printer and I just went to convert the spider I took off a the newer printer (2015 model) and apparently MG changed the spiders somewhere along the way and added a few more holes.

I think my next option is going to try and print a filler block corner that could attach to the bottom and maybe use a heat-set insert to fill the hole this way it would be threaded for a leveling screw. I'm not sure how much heat would transfer down through the level screw though....

Back to the drawing board for now....

[Jules]

Not sure if this helps, but that looks like the setup that they use on the new machines that they ship out - only differences are in the shape of the little rubber corner bumpers. The heated bed plate sits directly on the leveling screws.

And it looks like they have the single set screw hole that runs through the side to hold the leveling screw in place. The leveling screw comes in from underneath, the two on the side that hold the rubber bumpers go down.

Although your center hole does look bigger from that photo - so it might not work.

[sthone]

And it looks like they have drilled a single set screw hole that runs through the side to hold the leveling screw in place. The leveling screw comes in from underneath, the two on the side that hold the rubber bumpers go down.

That's how I did the first conversion I just copied the beta version spider, but yeah these newer Rev. D spiders have that huge hole where the leveling screw would have to go. (wonder what the idea behind that was) I think I might just thread the hole and make a plug that fits in the hole and then tap the center of that plug for a leveling screw. Least this way I could still probably cross drill it for the locking setscrew Ii I did the printed corner idea with a heat set insert I wouldn't be able to do that.

[jimc]

interesting, i just took the extra spider i have in my drawer to look at it. this came off my red machine which was one of the pre-2013 models with the stainless frame. this was a used machine i got from rick. that spider has the big holes as well. not sure the history of the machine. perhaps that was not the original spider. im not really sure. if it was then those holes were there on old m2's. rev a i guess.