Sixteen months have been passed since my last post but I have not stopped reading the forum. Yes, the machine building was delayed, but I had to prepare surface fundamental for the beast. I got approved ( green light from wife ) and started to adapt the future workshop.

Pics will follow.

Here it is. Leveling first.

The progress.

Almost finished.

Walls and ceiling colored white, with homemade neon armatures.:)

For the start I would need for a angle grinder ( big one ) that I intend to use as a chop saw. The choice was chinese industrial tools brand INGCO. It's something between quality and price. Powerfull grinder 2100 W.

I like clear and nice cuts.
So, this is my DIY stand for angle grinder.:)

Nice looking chop saw jig.
Necessity is the mother of invention.

Steel cut and construction started (angle grinder did nice and precise cuts ). The metal frame will be all joined with screws. Steel was new but stayed couple of months outside, there is surface corrosion which I will remove before painting.

Here are some pics of the progress.

Well along the way. Looks great!

Thank you for the encourage Jack.

The building continues this weekend. I use stick welder. These red magnet arrow holders are terrific, 5 USD each.:)

I've got custom made plasma cut 6mm plates for bolting legs an frame. Small welds and pivot drilled with this old drill that I bought on junkyard for 10 bucks.

It came out that the old drill is METABO with gear box inside. It 'eats' steel like butter with only 200 W.:D

Everything done on place without stand drill.

If you are indeed bolting all joints only ( I notice the tackwelds, but I think for drilling only ? ) you better use two bolts on those joints to create a more rigid construction. One bolt creates a pivoting joint where the table surface mdf and front and back frame are the only parts preventing racking from quare to parallelogram. In Cnc table frames you want everything as square and rigid as you can. If you weld the subbeams you do not have the pivot action.

Thank you Fox for your advice. You are right, there is possibility for pivoting, except I Secure the bolts for front and back frame with legs ( easier one ) than drilling second hole in crossbeams and beams ( there is no access / or one side of '[' channel must be additionally cut off for drill access what does not make me happy ). I want to use as less as possible welds because I would like to leave a chance for disassemble, moving and transporting, otherwise it would be pity to cut and grind this awesome machine.

I can weld cross members anytime if comes to necessity.

Here is the pic of joint plate ( legs / front - back frame ). Pls tell me your opinion.

Somewhere on the forum I found the idea of making own bevel shims. I'll need them for bolting cross memebers to main beams.

The cut-off pieces from main beams are used for this purpose. Making something from 'nothing' make me fell happy.

There will be some time and work consuming but the bevel match ideally.;)

In meantime laser cut parts are finished and bent. All done locally for a good price. Bending cost me only 5$.;)

I started building from upside down. Drilled also holes for bolting cross bearers on lowest frame horizontal parts ( for eventually future moving bed, lower for cca. 600mm, and upgrading the machine to another version, who knows? ).

All steel parts marked and ready for disassembling and painting.

You may want to use a set of punches to mark your steel. Easy to paint over the numbers and forget where you are .... wont say how I know these things :o :D

You are right Mark. It didn't come to my mind they would be covered.:o. You saved me a lot of messy time. Thank you.

It is a horrible weather with rain these days, weather forecast says it will be so whole week. So painting delayed.

Beast took apart and assembled on it's legs. Bolts hard tighten.

Here I come guys to the discussion we had at the beginning of this thread.

We have the situation here.

You can see what happens with top flanges of my 'I' beams. Not laying in the plane.

Choosing a relatively flat beam lowers the cost and saves time later.

Only two solutions now are to mill it flat or level with epoxy, none of them are cheap as 100$ a beam or easy as taking a look at couple of pieces for level

you could make rails with small leveling screws threaded in far side so you have two pints of contact and can set the rails level and then fill the void with "filler" of your choice

Yesterday I went through completely different way for resolving this 'headache'.
I got this idea from far beginning and here's what I've done:

I precisely "plastic surgery" cut line all along the beams 25mm under the top flange ( this height come from position of the angle grinder ) with 1mm steel cutting disk.

Future angle iron rail set as a beneath support for cutting disk and one screw of the grinder sliding to the top flange surface.

Levelling epoxy isnt that expensive to avoid levelling with this method. I just bought to me some. Price was 15,50€+VAT per kg.

My comment for belt drive is: use HTD profile, it doesnt have backlash. My first mechmate uses HTD5M profile. With T5 i think problems are quaranteed.

The "Surgery" took 2 hrs with most time used for inside cut ( I jumped over the cross members with some small hurts between the legs:o).

The another beam cut done easy. It was from outside.:D

The cut depth is 4mm.

Next, I made these "special tools" (two of them) from scrap parts laying around with few welds and with the help of the future Mechmate user applied force on the top flange at the same time.

End plates will fix it, and to be on the safe side I put small welds in the groove along the cut.

Voila, flanges are in plane, we are back in the game.:D

I honestly have not seen that done in all the 100+ builds of a MM. Unique solution. Are you planning on welding a few spots to keep the kerf from separating?

My suggestion is to weld crosswise on I beam some reinforcments like on picture
Attachment 15753
And then weld the cut.

Ivo, imo better don't suggest to weld the cut entirely, the main beam will go bananas on him, bending all over the place, even with the helpers.

Sean he writes it just above your question, that he already did little welds along the groove.

I do not think this was the best solution nor the simplest, shimming the beam would have been easier and better imo cause you kept the integrity intact. Now you introduced weakness where you did not want it in your main beam, where you want a perfect solid place to mount your rails.

But with small, say 10 mm welds or so and alternating ( from side to side and front to back etc) welding sequence along the cut on both ends of the beam, it should become strong enough once again without distorting. Make sure you let it cool in between, let's when you have 4 welds ( 2 each side) on, 8 welds on, 12 welds and so on. When one beam is cooling you can weld on the other etc.

Good welding sequences save the day when it comes to keep things straight, or making them straighter for that matter.
See Gerald's straitening techniques for example where he advised to weld along a bend beam to straigthen it out, to see how much influence a little welding( read heat) can have on a piece of straight (or bend) steel that weighs a hundred kilo.

Sean, either without spot welds the beam has it's integrity. The main role in this case will fall to 'end plates'. In addition, the kerf is only half of the vertical section of "I" beam( 4mm from 8mm). With kerf, I removed material for 'line guided torsion'( that's why the torsion is done in the same momentum in 1/3 of beam length from ends) I applied to upper flange. 2-3 strikes with homemade 'lever tool' did the job.

Ivo, there will no be need for reinforcements, 'end plates' will do the same. Welding all along the cut will make strong deformations. Only spot welds 250mm between.

Fox, The biggest force that strikes the beam is sum of ( half weight of gantry + Y car and everything that goes in it), when the Y-car is nearest to the beam. So beam is generally affected by vertical force and small moment of that force created by linear rail distance to vertical axis of the beam.

So, we've got beams back to the plain without putting thick shims, resins or similar that make rails standing on 'glass legs' or that's what I'm feeling about.:)

After welding beams kept very straight and strong too.

Thank you guys for the comments and not letting go out of the right way.

Pics will explain everything.

This weekend I continued with cutting down angle iron 60 x 60 mm to 28 mm. Used one disk 1mm thick for one rail.

It's very important to open slightly ( bend ) cut off part just before breaking through ( opposite, there is danger of disk to be catch inside the kerf and at cca 11.000 rpm:eek: flying parts of disk that are life dangerous), or just stop grinding before breaking through and separate the top part with pliers with twisting. I had very unpleasant experience that make me aware.

I want to share with future builders.

I used 'sandwich' system, plywood inside and console surface for angle grinder sliding.

Pics worth thousand words or some others tell me:)

It took 4 hours to cut all the rails.
I'm satisfied with cut quality.

Rails final grinding did with 40 grit sanding discs mounted on grinding disc 6mm thick. Height monitored at single pass in multiple points along the lenght. All done within 0.2 mm tolerance.

Skate worked perfectly. It took a little bit more time for the first rail but when you get experienced...It's easier.

Don't forget cutting forces my friend, and you'll be amazed how much even a big table will be shaking ( sideways !) when the thing is rapidly moving along it's axes, because you're stopping and accelerating your entire Z +gantry.

I'll keep that in mind, thank you Fox.

Y-car parts assembled and tightened with clamps. I needed scrap metal parts to fold and tight the Y-car. Threaded rods are perfect for fine tuning. Everything square and welding started.

Granite tile is reference surface.

X-rails marked and drilled.