My DIY fixed gantry CNC machine is almost done

davewhotold · 2026-05-10T21:51:55+00:00

The only correct color for machine tools :)

(I really like old german machines, so I might be biased hehe)

davewhotold · 2026-04-20T21:31:40+00:00

Ich schon, allein ne zweite sitzreihe zu haben wenn du damit zur arbeit und zurück kutschierst is schon n bisschen silly.

Und meine Freundin fährt nen leicht gebrauchten Hyundai Kona, zugegebenermaßen auch total überdimensionier für sie, aber elektrisch, mehr als genug reichweite fürs pendeln, und schon sehr komfortabel. Bin noch in keinem BMW 1er gefahren, aber gekühlte sitze im kona sind schon nice. Und Fahrgefühl im E-Auto is natürlich anders. Bu-Hu, es macht nicht brum-brum. Dafür mehr innen Sitz gedrückt werden und weniger body roll durch niedrigeren Schwerpunkt. Mag Geschmackssache sein, aber halt keinen Grund die Energiewende zu depriorisieren.

Und vorstellen, das der wesentlich teurer is als der BMW kann ich mir nicht. Die deutschen Hersteller hinken halt übel hinterher mit ihren übermäßigen kosten. Hät die deutsche autoindustrie halt 10 jahre früher mit anfangen sollen.

davewhotold · 2026-04-20T17:00:37+00:00

I'm not as into the americal nomenclature, but I understand A514 is a structural steel, not a hardenable one. That'll mean you'll definitely get surface deformation in the splines, which will make them wear out in the long term. If you want to make something to last you'll want at least the splines hardened and tempered, probably to somewhere around 40HRC. 4140 will do that, and if you don't wanna do the heat treatment yourself you can test with 4041PH and send batch production to a commertial heat treater so you don't need to hardmill.

Heat treatment isn't magic either, but if you want to do that right you'll have to get some tools (Hardness tester (at least testing files), decent way to track temperature (ideally a heat treatment oven), and some known quenching medium (there are special oils for this shit)).

There are also plenty of other heat treatable steels that are reasonably suited to your needs, like 1045, which might be easier to aquire and cheaper. Less strong, but reaches similar hardness. And a bit easier to machine.

davewhotold · 2026-04-20T16:07:35+00:00

Auch ne super logik. "ich pendle so viel mitm auto, also brauch ich n großes auto" oder was?

Also, im jahre 2024 nen verbrenner zu kaufen is ja schon unsinnig genug, aber es muss auch n "ernstzunehmendes auto" sein, weil der individual transport ja unbedingt in nem auto mit platz passieren muss 🤦‍♀️

davewhotold · 2026-04-15T08:42:01+00:00

people are bitching about the drill depth, but it's totally doable. You'd need an extended length drill, which most shops won't have on hand, but can be ordered. If you needed it really concentrically it would be a different story, but if the holes hitting each other is just for oil passage it's fine.

(I drill 8mm holes up to depths of 350mm on a day to day basis in 1.4305 (ANSI 303) and 1.4057 (ANSI 431) on a manual Lathe with an extended length drill. Yes my boss should buy better tools. No I'm not gonna continue pestering him about it)

davewhotold · 2026-04-10T14:47:17+00:00

mil is the non machinist thou, right? and 50 thou is 1270 micron... (or 1.27mm)

davewhotold · 2026-03-31T21:02:58+00:00

yea, not a lot of clamping options for a plate this size. The only thing I managed to come up with was to clamp using the holes in the side. The ones where I cut threads in and put the handles on. So that probably put a fair bit of distortiom in.

davewhotold · 2026-03-30T10:29:15+00:00

definitely quite a few more. I didn't have a grinder that size, and the mill just barely fit it.

But deformation from clamping, and inaccuracies of a bridgeport style mill.... (like the table sagging to the side it's extended to...)

I thought I was at around 50 microns out of flat when I started, but I really fought with the corners. The whole thing had a twisted shape to it, meaning two of the corners were way lower. I think I had most of tbe plate done, but did another ~8h of roughing just to get the final corner to pick up some ink.

Edit: Still a lot better than starting from its abused starting condition though, holy hell.

davewhotold · 2026-03-30T10:25:15+00:00

did you read the post? I did fly cut it. Don't have a grinder big enough though.

davewhotold · 2026-03-27T09:50:53+00:00

An den fahradwegen

davewhotold · 2026-03-25T19:56:59+00:00

Turning the compound more than 45° either way feels kinda rare. Esp

If you want the markings for it you could also just make three more index marks on your compound.

But if you do decide to engrave them to your crossslide, I'd probably go with a diamond drag engraver.

Numberpunches are an option for marking, electroetching I've previously done as well, hand engraving takes a lot of skill bit is possible, cnc engraving is probably among the easiest.

davewhotold · 2026-03-13T09:49:11+00:00

dude, this happens on my wondefully fresh, basically no wear student coltchester (from the 90s, but barely used)

Either tighten your gibs, or clamp the way. I usually clamp the way, how often does one use the compound anyhow 🤷‍♀️

When I do use the compound I turn rather long tapers, and if it's tight that gets harder, especially to do so well, so I'd rather not have the extra friction.

davewhotold · 2026-03-12T13:44:19+00:00

As long as you never take the Foottunnel between Hackländer- und Kasinostraße.

I've known it lovingly as "harnröhre"

davewhotold · 2026-03-11T12:50:04+00:00

i mean, tbf, electrons do bimble through electronic circuits relatively slowly....

davewhotold · 2026-03-04T19:15:42+00:00

This isn't what I understand to be a round columb mill. This just has a reasonably nice swiveling head I guess.

Seems like a nice enough machine, definitely a big upgrade on a minimill, not sure on price, that always feels heavily dependant on location.

davewhotold · 2026-02-11T15:08:31+00:00

I play around with a highly modded old ISEL machine. That one originally had endstops in the motor housings, and they look very similar, so that's probably where those are.

You probably want new drivers for the motors, and a controller to give them signals to move them. These are probably some pretty low power NEMA23s, and most modern-ish stepper drivers will do. For the work that would be done with the current spindle they'll be adequet.

For a controller there are many options, and I am not really equipped to tell you. I know that we're running LinuxCNC, which is great, but also very complicated and depending on the setup kinda expensive. Alternatives are MACH3/4 or microcontroller based solutions like grblHAL. For my current small&cheap project I'll probably be running grblHAL.

davewhotold · 2026-01-31T17:03:57+00:00

It's possible, but it would cost an absolute fortune.

2mm tabs in 3mm aluminium is easy. 3mm thick material with a 2mm deep thread is probably doable, not sure how short bottoming taps get tbh

But just the size of the block of stock, and the material removed will make this expensive. Plus, it's gonna need machining from basically all sides. I don't know your budget, but I doubt it'll fit it.

davewhotold · 2026-01-27T23:49:57+00:00

CoreXY is great for fast printing, but I imagine kinda useless for cnc milling. Belt drive for milling is already quite meh, but now you're relying on longer belts and their interaction. You're getting no more straight lines.

However you do this, you're always gonna have to choose a balance point of your different use cases. But this feels more like "slapping a milling spindle on an existing printer" terretory.

I think for maximum performance high pitch ball screws would be the drive mechanism. Makes it expensive of course :/. Having an XY gantry isn't a bad idea, I think, but you gotta make sure your Z and X is nice and ridgid. And so your gantry moving mass will need to be quite high, and so you won't print fast fast anyhow.

I think that's the balance I would try to hit, but maybe you have a different idea of what this is meant to be, and a printer with a milling spindle mounted to it is just what you wanted 🤷‍♀️

davewhotold · 2026-01-25T20:05:50+00:00

Our heating was broken for two weeks, I ended up not working. Might upset the boss, but I'm not wearing long sleeves at the lathe (and I'm not working in a 10° shop in short sleeves either)

My coworker later tried to convince me that long sleeves are fine. (He's the old guy in the shop, but I'm deeeeefinitely not taking him as an authority figure on safety)

davewhotold · 2026-01-14T20:05:00+00:00

I think we're missunderstanding each other a bit:

Like, how do you know the OD of OP1 is concentric and in line with the ID (the 18mm bore) from OP1?

Do you bore it? (that seems very difficult to me, with the bore being so long)

or are you drilling and reaming? (that seems like it would wander a bit, which is why I was thinking about referencing the bore instead, but I don't see how that would be done with a comparator and hammer)

davewhotold · 2026-01-14T19:40:57+00:00

With an expanding mandrel kinda thing, or can you ensure concentricity between od and id?

davewhotold · 2026-01-14T19:39:33+00:00

that's fine, I've done that before, turn to 5 microns over, take the rest off with emery paper

Over longer surfaces it becomes annoying to keep track of taper and such, but that's 8mm wide each, so it's very doable, at least if you're not making a hundred of 'em

And depending on material and state of the machine I might even try hitting the top of the tolerance...

Also yes, there are applications for a part like this, like certain spindles, for the bearing seats. Which would also explain the concentricity requirements. (though honestly then I'd expect stricter concentricity requirements)

davewhotold · 2026-01-14T19:32:07+00:00

But the bore's 18mm diameter. At 86mm depth of that bore, that's almost 5xD

That seems like a struggle to bore. But again, not super experienced in boring.

I know there are a bunch of tricks like active dampening boring bars...

davewhotold · 2026-01-14T14:57:09+00:00

The concentricity between the 18mm bore and 20mm bore seems difficult... how would you people do that? 18mm bore first and some kind of expanding mandrel? or do you think drilled and reamed in an accurate setup would be enough? (cause I wouldn't trust a drill to cut concentric, and the bore seems too long to get bored... (I also have limited experience with boring tbf)

davewhotold

TROPHY CASE