JGRO metal cutting machine concept???

[rhino]

I had an idea last night when i was going to bed. would the jgro design be possible to cut steel if it were made from thicker & larger parts made from cast iron (maybe even a single casting of the gantry???), ball/acme screws, linear slides, etc? it seems to be a good rigid design to cut wood, and i think someone in a post said it could cut aluminium(???). i realise it would need a custom spindle/headstock and a heap of other doovy-lackies like a counterweight(for the headstock).

can i have some feedback on this concept please.

thanx.

RHINO.

[dberndt]

Its not practical IMO.

Years of standard mills look like they do for a reason. Getting a gantry that tall stiff enough to machine to the kind of tolerances most machinists work to is going to be pretty tricky. Maybe if you plan on using some big honking I-beams for most of the construction. Even then...

[HayTay]

Originally Posted by rhino I had an idea last night when i was going to bed. would the jgro design be possible to cut steel if it were made from thicker & larger parts made from cast iron (maybe even a single casting of the gantry???), ball/acme screws, linear slides, etc? it seems to be a good rigid design to cut wood, and i think someone in a post said it could cut aluminium(???). i realise it would need a custom spindle/headstock and a heap of other doovy-lackies like a counterweight(for the headstock). can i have some feedback on this concept please.

If you did all of that it wouldn't be jgro's design. The unsupported rails would be a definite no-no.

After going to the expense of making patterns for the iron castings, the sand, the iron, the propane (heat source), etc., and a MILLING MACHINE to cut the bearing holes and other features to size, wouldn't it be more cost effective to purchase a Milling Machine and convert it to CNC??? Just a thought.

Rhino, in all the time I've been on this forum I don't think I've seen a DIY cast iron gantry router. Be the first and prove us wrong!!!

Originally Posted by dberndt Maybe if you plan on using some big honking I-beams for most of the construction.

Anyone who uses the phrase "big honkin" is just COOL, man! Keep On Truckin'... Seriously though, the phrase "big honkin" isn't used nearly enough in everyday conversation. Just curious, when you refer to something as "big honkin", do people look at you funny too?


HayTay

[pminmo]

Sometimes you just have to do things even if it is more expensive. Look at all the scaled down models of IC, sterling and steam engines. To me the journey is the interesting part of the trip, not the destination.

[dberndt]

The entire purpose of calling something big honking is to show the silliness of working on of the scale that someone is working on. Like having a jet powered lawn mower and a 1/10th acre yard. It's a big honkin lawn mower alright.

Plus people look at me funny all the time even if I don't say things like big honkin.

[Geof]

Rhino if you really want to indulge in some silliness I have something for you. Not big honking I-beams, big honking tubes 4" x 4" by 1/4" wall welded into a gantry 10 feet long and 2 feet deep designed to carry a 500 lb Y and Z axis assembly without noticeable deflection.

[Geof]

Incidentally big honking metal cutting gantry machines are available commercially. I never did complete my U-build (obviously) I bought one; 120" X, 60" Y, 24" Z.

[dberndt]

Yes. These machines exist and are available. A good way to deal with large but not deep work pieces. Such as full 4'x8' sheets.

But as it pertains to JGRO style/size machine. I dont believe the OP was talking about building a giant gantry. Just a similar size machine of stronger components to enable steel cutting. The point I was trying to make was that without increasing the mass and rigidity of the gantry, quality of the linear bearings, etc you aren't going to get a great resulting product. The cost to do all the upgrades, would put you in the same territory as the cost of a more traditional turret or bed mill. Having all that mass hanging high up above the X axis ways (assuming x axis carries the gantry) really means you need some beefy ways to keep everything up there stable and chatter free. A Moving table that sits directly on top of its ways is only exposed to the twisting forces apply but the cutter and not those of gravity as well. Its easier.

[rhino]

Originally Posted by Geof Rhino if you really want to indulge in some silliness I have something for you. Not big honking I-beams, big honking tubes 4" x 4" by 1/4" wall welded into a gantry 10 feet long and 2 feet deep designed to carry a 500 lb Y and Z axis assembly without noticeable deflection.

sorry bud! i can't even imagine the postage/shipping of those buggers! better keep them in the garden shed for the next goose that comes along. i realise the idea was unpracticle, but thank everyone who posted theyre PRO's and CON's.

Rhino