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Ambihelical Hexnut
Aug 5, 2008


biracial bear for uncut posted:

You can use your last hole in one setup as your first alignment hole when moving setups. Maybe one program working off one edge datum, then the sequential programs basically calling X/Y zero the hole you locate off of in the subsequent setups.

As long as you don't loosen the vise bolts on the table you won't have to worry much about parallelism as you reset X on subsequent setups.

If you have some manual machining experience this should be easy to do, all you're doing is using the CNC controller to do a series of holes more rapidly than you can do it manually.

Thanks for the ideas. I thought about bolting an endstop rod smaller in diameter than the holes to the table to accomplish just this; the good news is as long as the holes are spaced measuring-tape accurate down the bar there really won't be any cost to being lazy, they really only need to be accurate in Y as illustrated.

Bad news is my G540 might have died in anticipation. No lights, redid the wires, checked multiple PSUs, replaced the fuse, measured the resistance across the r040, all of which check out, but nothing works. Gecko tech support blew my dick clean off: calling on a friday afternoon I had a dude walking me through probing components with a dmm over the phone within 2 minutes. It is now clear that god does not want me to have a working mill, but a positive tech support experience really lifted my spirits.

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Ambihelical Hexnut
Aug 5, 2008


While I await the return of my G540, let's gently caress around:

I originally intended to make a heavy table base for the plasma but thinking about the design I wanted something I could tear down. This led me to consider simply making legs out of extrusion, but I already have steel so why not just make my own legs and braces?

3x2" 11ga legs with a bracket made of 3/32" into which I made four holes scribed with calipers that line up with the t-slots on the extrusion. I don't know how to weld but I've gotten far enough with this amazon stick welder that nothing's falling apart yet. Here's how big a 2x4"x72" extrusion with a single 36" leg is compared to a Shapeoko XXL.



The grinder hides most of my crimes:



Three more legs to go. Then feet. Then braces.

[edit] Two more. gently caress this is too big for my garage.

Ambihelical Hexnut fucked around with this message at 02:02 on May 23, 2020

shovelbum
Oct 21, 2010



Fallen Rib

Hows the shapeoko been? Getting much use out of it? I never ended up getting one, picked up a 3D printer instead and now I've gotten used to having the garage free for the actual car after cleaning it out.

Ambihelical Hexnut
Aug 5, 2008


I've gotten a ridiculous amount of use out of it; I pre-ordered in early 2015, upgraded to XXL in 2017, ran a small sign making business for a couple years with it, and have used it to make all kinds of plaques and engravings for my day job the entire time. This is in addition to things I do for myself and the family. These days it's a pretty mature product and works very well if you get dust collection and workholding sorted.

Everyone on the internet wants to pretend that it is also a mill, but it is not a mill. It's a gantry router for sheet stock.

shovelbum
Oct 21, 2010



Fallen Rib

Yeah I never got why people are so keen to try to use them for mills on metal etc when there are so many applications for the materials it can actually handle. The plasma seems like a good idea, it's a nice process that I haven't worked with since school and the simple plasma CNCs don't need to be as pricy as they are. I can't cut a straight line with a torch to save my life so I look forward to seeing your progress.

Ambihelical Hexnut
Aug 5, 2008


Okay after another full day of this I have four legs and four supports. Size mockup:



a) I'm going to have to rearrange my garage when it comes time to assemble this thing.
b) If I make it a foot taller I can park the mower underneath. Probably shouldn't.



Support bars cut. The trusty harbor freight 4x6 bandsaw takes like 30 minutes per cut on this tubing. Each one support needs two 45 degree cuts, then a piece of flat bar cut out to make a bracket for the extrusion. Then you have 8 edges and 8 corners per support which need to be sanded and given a small bevel.

Then clamp it together on the table, tack one side, undo all the clamps, tack the other side, undo all the clamps, and start welding about an inch at a time alternating sides so it doesn't warp/etc. It goes much slower in real life than on youtube.

Bad welding:


Hide with grindy:


Then go back over it again because you can still see pits and low areas, then grind it again.

I'm extremely tired of drilling brackets by hand, can't wait for the stupid G540 to get back so I can just mill them.

Ambihelical Hexnut
Aug 5, 2008




Mocking it up. Need to add feet plates.

biracial bear for uncut
Jun 9, 2009

ask me about being the most obnoxious person of all time

Karia posted:

Rather than indicating in the hole every time you move, you can keep your drillbit down in the hole (plunged down past the flutes so the shank is in the hole), unclamp, and use the X axis to drag the bar over. You'll probably lose a thou or two every time because the hole's going to be slightly oversize, but maybe that's acceptable, and once you know that offset you can compensate for it if you want.

I was going to say this in my original post, but I know anybody with any industrial CNC machinist background would have a heart attack at the thought of using the positioning motors on a CNC to drag stock around (because they aren't designed with that in mind).

Also it's just bad practice in general, you can bend or otherwise break a tool if the stock is heavy enough.

CarForumPoster
Jun 26, 2013


biracial bear for uncut posted:

I was going to say this in my original post, but I know anybody with any industrial CNC machinist background would have a heart attack at the thought of using the positioning motors on a CNC to drag stock around (because they aren't designed with that in mind).

Also it's just bad practice in general, you can bend or otherwise break a tool if the stock is heavy enough.

I have an industrial CNC machinist background, though I've been out of it for >5 years. There are many many examples of this done in industry and lots of tooling out there for it. Its almost certainly within the design limits of the pictured machine, but if theres any question, look up the specs.

That said, Karia's specific solution is likely not repeatable within a few thou as hoped. Drilling this in a vice is not likely to give the desired results, but tolerances weren't mentioned.

You can bang out a fixture plate for this hat will likely be better than what you want for a few bucks and maybe 1 hour of time. Move it by hand unless you gotta do a bunch of them. You can position the below orange piece as far apart as needed, just indicate them in on some machined square feature. Support the center.

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mekilljoydammit
Jan 28, 2016

Me have motors that scream to 10,000rpm. Me have more cars than Pick and Pull

So was reading the wiring manual for the Fadal VMCs yesterday to try to figure out how hard it would be to wire up the special single phase transformer when I realized... the spindle just goes to current taps on the "this goes to the breaker" side of the transformer, the transformer doesn't do anything to the power going to the spindle drive.

And on the single phase version it literally only hooks up 2 instead of 3 wires.

Motherfucker... the only thing the transformer is there for is to make 120V to run the controls and poo poo.

So long story short I'm 95% sure I can get one of these suckers and run it on the circuit that used to go to my hot tub. Now to build a shed!

Ambihelical Hexnut
Aug 5, 2008


Wow thanks for the fixturing input guys. I agree that some kind of indexable plate will be the easiest and most accurate. I don't have the stuff on hand to get beautiful precision dowels into a beautiful plate, but I also don't need to face the top of the steel so a few well placed screws could probably serve as both a repeatable edge and clamps.

Still not there yet because I keep loving with my mill: today's project was getting the LMS pwm spindle controller installed so I can control my spindle from mach3/gcode instead of just manually. It is an add-on board, and curiously a replacement chip to put in a socket on the brushless motor controller.
Board installed (lil guy on bottom):



Finally using up every drat pin on the G540. I wired up a 6-pin G16 for limit switches, another one for the spindle control, and a stereo minijack for the touch probe:



I don't know why Gecko decided to put the pins along the bottom requiring an immediate 90 degree bend and ensuring you have to remove the controller to change anything, but it's my main complaint. I have one more remaining thing to cram into this crowded box of electrical noise which is a 48v cooling fan and G540 heatsinks.

biracial bear for uncut
Jun 9, 2009

ask me about being the most obnoxious person of all time

Get some roll spring pins from Mcmaster-Carr and tap them into drilled holes with a mallet. They'll work better than screws and be a good indexing surface as well as long as you have the cut facing away from the side you want to index off of.

Karia
Mar 27, 2013

Self-portrait, Snake on a Plane
Oil painting, c. 1482-1484
Leonardo DaVinci (1452-1591)



College Slice

biracial bear for uncut posted:

I was going to say this in my original post, but I know anybody with any industrial CNC machinist background would have a heart attack at the thought of using the positioning motors on a CNC to drag stock around (because they aren't designed with that in mind).

Also it's just bad practice in general, you can bend or otherwise break a tool if the stock is heavy enough.

I have ~8 years of industry experience. The motors wouldn't be the concern unless they're very under-spec'd. The only thing I'd be worried about is the spindle bearings: they're not designed to take static load. You'd need to minimize the bending moment by plunging the tool down as deep as possible into the material so you're running on the shank (that would also improve accuracy since you're not locating on the flutes.)

Realistically, though, the load here is honestly pretty small, easily <20 lb-f assuming the stock is well supported on both ends so it's not bending the tool with its weight (note the linear bearings being used to support the cantilevered end.) Accuracy can definitely vary, but my understanding was that that dimension wasn't critical, and if it was you could use this method to get close then indicate the holes in. The more critical dimension (distance to the edge of the material) is pretty much exclusively controlled by the vise.

I'll agree making a fixture plate is a better idea, though.

biracial bear for uncut
Jun 9, 2009

ask me about being the most obnoxious person of all time

Karia posted:

I have ~8 years of industry experience. The motors wouldn't be the concern unless they're very under-spec'd. The only thing I'd be worried about is the spindle bearings: they're not designed to take static load. You'd need to minimize the bending moment by plunging the tool down as deep as possible into the material so you're running on the shank (that would also improve accuracy since you're not locating on the flutes.)

Realistically, though, the load here is honestly pretty small, easily <20 lb-f assuming the stock is well supported on both ends so it's not bending the tool with its weight (note the linear bearings being used to support the cantilevered end.) Accuracy can definitely vary, but my understanding was that that dimension wasn't critical, and if it was you could use this method to get close then indicate the holes in. The more critical dimension (distance to the edge of the material) is pretty much exclusively controlled by the vise.

I'll agree making a fixture plate is a better idea, though.

Most of the CNC machines I'm familiar with are large capacity routers that machine nested parts out of huge blocks of stock, so they definitely aren't meant to move 10' x 20' x 3"+ thick sheets of stock around (you really don't want to put that kind of load on the spindle anyway, shank attached or not). Even if it isn't steel, lumber and plastics get really heavy at that size.

EDIT: and yeah, when I mentioned that freakout it was from personal experience seeing the guys in the shop drill a 1/2" rod into the end of a piece of stock and then hook it onto the spindle head by jogging the spindle down to it and tightening a collet onto it before using the Z axis to lift the end and the X-axis to drag it onto the table.

biracial bear for uncut fucked around with this message at 17:58 on May 27, 2020

Karia
Mar 27, 2013

Self-portrait, Snake on a Plane
Oil painting, c. 1482-1484
Leonardo DaVinci (1452-1591)



College Slice

biracial bear for uncut posted:

Most of the CNC machines I'm familiar with are large capacity routers that machine nested parts out of huge blocks of stock, so they definitely aren't meant to move 10' x 20' x 3"+ thick sheets of stock around (you really don't want to put that kind of load on the spindle anyway, shank attached or not). Even if it isn't steel, lumber and plastics get really heavy at that size.

EDIT: and yeah, when I mentioned that freakout it was from personal experience seeing the guys in the shop drill a 1/2" rod into the end of a piece of stock and then hook it onto the spindle head by jogging the spindle down to it and tightening a collet onto it before using the Z axis to lift the end and the X-axis to drag it onto the table.



Yeah, I understand your hesitance! Moving well-supported segments of bar stock short distances on a low-friction bearing is one thing, but yanking around a (conservatively) 1100lb piece of wood with a router spindle using a crappy single point of support is a flat "nope." I hope that person no longer works with you.

EDIT: Uh, just to clarify: I mean I hope they got fired, not that I hope that they died.

Karia fucked around with this message at 18:38 on May 27, 2020

biracial bear for uncut
Jun 9, 2009

ask me about being the most obnoxious person of all time

Yeah, they got fired, but not for that.

Ambihelical Hexnut
Aug 5, 2008


Got some aluminum plate, roll pins, and various accouterments on the way in. In the mean time, for the first time in a long time, I was able to make some cuts to test everything out. Homing, soft limits, spindle control all working great now. I found a used bimba air cylinder on ebay for $14 and the hoss machine designs for the power drawbar on archive.org, so that's the next thing this machine needs. All I wanted was an enclosure, just one enclosure, and I wouldn't give it to me.

Since I didn't sing enough praises for Gecko customer support last time: they received my non-working G540, which I purchased second hand three years ago, and the original owner apparently bought in 2014, replaced a damaged board, and mailed it back to me for $0.00.

mekilljoydammit
Jan 28, 2016

Me have motors that scream to 10,000rpm. Me have more cars than Pick and Pull

Ambihelical Hexnut posted:

Since I didn't sing enough praises for Gecko customer support last time: they received my non-working G540, which I purchased second hand three years ago, and the original owner apparently bought in 2014, replaced a damaged board, and mailed it back to me for $0.00.

That influences decisions on my part.

Ambihelical Hexnut
Aug 5, 2008


CarForumPoster posted:

I have an industrial CNC machinist background, though I've been out of it for >5 years. There are many many examples of this done in industry and lots of tooling out there for it. Its almost certainly within the design limits of the pictured machine, but if theres any question, look up the specs.

That said, Karia's specific solution is likely not repeatable within a few thou as hoped. Drilling this in a vice is not likely to give the desired results, but tolerances weren't mentioned.

You can bang out a fixture plate for this hat will likely be better than what you want for a few bucks and maybe 1 hour of time. Move it by hand unless you gotta do a bunch of them. You can position the below orange piece as far apart as needed, just indicate them in on some machined square feature. Support the center.


I ordered some stock to do it this way but got impatient today to see if I could achieve something similar with what I have on hand:



Currently there are three pins tapped in for positioning the bar in Y. The two bolts on the right are in threaded holes spaced the same as the holes we'll be drilling for the rails, so they can locate the bar in X and clamp it down. The corresponding two holes on the left are relief space for drilling the two new holes in the bar. The remaining three holes can be used for pins or clamps. So with this version I'd just run the code to drill two new holes, then unscrew, slide the bar down, and screw it in at those holes. Clamp at the bottom left corner with another screw head if necessary.

I've got a much wider piece of aluminum bar coming in that should make it possible to do multiple sets of holes per pass but this is the basic concept. Think it'll work?

Also: I'd never looked to thingiverse for drawer organization before but I've been burning up the 3d printer this week making bins and collet holders:

Ambihelical Hexnut
Aug 5, 2008


gently caress it, let's roll:



It worked perfectly as-is. Unscrew two screws, move it down six inches, screw in two screws, cycle start. Easy cheesy. I supported both ends with rollers and put some flat stock under the bar on the left end of the table to keep it shimmed level.

sharkytm
Oct 9, 2003

Gimme Gimme Swedish Fish...

Fallen Rib

Ambihelical Hexnut posted:

gently caress it, let's roll:



It worked perfectly as-is. Unscrew two screws, move it down six inches, screw in two screws, cycle start. Easy cheesy. I supported both ends with rollers and put some flat stock under the bar on the left end of the table to keep it shimmed level.

I'm reminded of this so many times: 75% of machining is setup. Congrats on a simple, repeatable setup that accomplished the goal.

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Ambihelical Hexnut
Aug 5, 2008


Thanks!



Two y-axis rails (2x4) and one x-axis rail (2x2) bolted up. Getting the gantry mounted requires making plates to link each carriage cart and also hold upright supports for the x-axis. The carriage plates need to be 5" wide and 8.5" long, and I'll cut them from some 0.75" plate and use the mill just to drill the bolt holes since my Y-axis travel is only about 5" For the upright part I haven't decided, I could use a short length of extrusion or just mill a vertical plate. I also need to make a plate for the x axis carriage, and purchase a cheapo openbuilds z-axis for carrying the torch.

On the framing side I've now got the right taps and materials to finish my legs/feet so I can work on that too. Might need more 3x2 tubing depending upon how flimsy it feels assembled.

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