Big boy mill discussion

I wanted to start a discussion on getting a larger more capable vertical mill.
The Enco mill we have is nice but very limited in what it can do.

We need something much larger that is rigid.
I think a digital read out (DRO) is a necessity.

Something like this Grizzly model is the type that I would recommend.

http://www.grizzly.com/products/Grizzly-9-X-49-Vertical-Mill-with-Power-Feed-and-DRO/G0796

I’m not married to anything in particular, I am hesitant to get anything used unless we can get it throughly checked out.

A good used Bridgeport knee mill sells on eBay in the $2500 to $4000 range. If we watch eBay and CraigsList we can find a good used Bridgeport or equivalent in that range.
Watching the lists for six months, I’ve seen dozens come and go in this range.

Delivery would require a rigger or movable crane. They weigh near 900 pounds.

Additionally, almost all mills have 3 phase motors. Yesterday, Greg and I tracked the 3 Phase in the building.
We believe the three phase is wired in Delta as opposed to Y configuration. (no neutral) It is also very old, with brittle cloth insulation.
Further investigation will be required, but may prove somewhat problematic.

While in general I can get behind the possibility of old machines being better for the price, I am also well aware that even moderate condition machines can require pretty massive amounts of work to bring to fully capable condition, and without a surface grinder or even a surface plate to measure on, we would be hard pressed to do a good job of making improvements to a machine that had any measurable machine-way wear.

the more I think about it, given that and the (somewhat insane) opposition to having a VFD or rotary converter for powering a 3-phase machine, I think a new machine like what Brad is proposing may actually be the way to go. The grizzly lathe we have is quite nice for an import machine, and from what I have been reading, we could have similar expectations of the mills if we are careful in picking the right model. Grizzle offers most of those machines in single phase 220v, so no need for arguments about power.

buying new we also have a relatively secure source for replacement parts (grizzly stocks most replacements in US warehouses with 1-2 week turnaround, days if a close warehouse). We would also get assurance that the ways and screws are in good shape, and get to skip the “project” phase of getting a mill and go straight to machining.

I’m by no means going to throw my hat in against a good deal on a used mill, but I think new MAY be the better option for Hive13 and our current leadership bandwidth and facility constraints.

-Kevin

Does a DRO guarantee an option for CNC? Even if it would be Hive made or at least Hive installed later?

Not really.

CNC usually requires another level of drivetrain rigidity.
There are “kits” but they are usually compromises.
If you want CNC you should start with CNC (like the Tormach 440).

https://www.tormach.com/pcnc-440/

I think it would be super cool to have metal CNC capability, but it is another step.

Great to talk about on this thread though.

Brad

CNC conversions of manual mills tend to be pretty poor compromises.

I agree that If you want CNC you should start with CNC.

DRO just makes it so you don’t have to count handwheel turns.

I like this one:

image.png
https://www.thingiverse.com/thing:2551678

Newest corrosion resistant technology! I think the DRO is extra…

hey, there are things you could make with that that would be tough on a full size mill

Discussion considerations for mills. This warrants some research and discussion.
Between our collective experience and the network of contacts we can have in the area we should learn all that we can.
It warrants a wiki page, which eventually, I’ll initiate. Until then, please comment to the mailing list.

  1. What kind of precision do we really need? Are we looking for a manual beater, DRO honda or CNC ferrari? Each increment ramps the learning curve to even touch the mill.

  2. New vs Used vs Reconditioned - Tool dealer, eBay, Amazon or CraigsList? We need to explore sources and choices more.

  3. 1 phase VS 3 phase - or buy VFD to convert single to 3Ph <$200 per machine

  4. Inch vs Metric - Bridgeports are Inch, Chinese are metric.

  5. Accessory costs add up: collet sets, vice, boring bars, angle plates and rotary tables… Can we use our R8 collets and other tools with the new mill?

  6. If CNC is considered, the controller software becomes a critical element.

Dave

I would really lean toward a new Grizzly type of mill unless someone has the time to make a project out of it. I have heard plenty of stories of people thinking they got a great deal, only to find out things were bent/warped and that parts weren’t available. Sure Bridgeports are everywhere, but it doesn’t take much to really damage a machine tool.
I don’t want a project, I just want a nicer mill.
Let’s browse the various boards and see what is out there.
Heck, if someone donates a Bridgeport I’m open.

If we go the CNC route I’d chip in for something like the PCNC 1100. No clue what I’d do with it but I’d probably find something. I think Tormach might have deals from time to time for education. Maybe we could qualify.

Coy

Tormach makes nice CNC equipment. However, I’d have to vote against a Tormach.
WHY? - Everything requires a degree of programming. There are no manual feed wheels.

There are many styles of mill from Bport to Deckle and Maho. Each have strengths and quirks.
We need a device compatible with our members level of experience and lack thereof.

No one should use a CNC mill until they are very comfortable using a manual mill. There is just too much at stake with a CNC mill when you press RUN. its FAR less forgiving than a CNC router.

I can see Hive13 looking into a CNC mill sometime down the road, but a good manual mill should be first.

.

Also, going back to the taper/collet discussion:

My view is we don’t have enough mill tooling to really worry about what taper/collet a new mill would have. sure, it would be nice if we can use our existing R8 stuff, but we really only have ~6 collets, a drill chuck, and a slitting saw holder than we have no slitting saws for. It’s not like we have a whole set of tooling with carbide end mill holders, a boring head, a fly cutter holder, etc.

Also, if we get a decent mill that comes with even minimal tooling we should be able to make our own tool holders between the lathe and mill. even easier if we invest in a collet chuck set for the lathe.

I would lean toward doing some test stuff with the Shapeoko2 when it gets online.
I’ve seen some super cool wax/soap/plastic milling demonstrations.

There has been a lot of discussion on the interwebs about using the Shapeoko2 for Aluminum. Apparently if the Aluminum isn’t too hard, the bit is new, the feedrates are slow, spindle RPM is high, and the workpiece is well mounted, it can do some mild milling.
This might be a nice introduction to more precision CNC work at the Hive.

I’m not trying to jam the mill concept down anyone’s throat. Just wanted to think about the next steps for our metal working.

Let’s keep talking. . .

thought the shapeoko had been converted for pcb milling?

I don’t think the Shapeoko has been modified to prevent soft metal milling.
I think it was resurrected to do PCB work.
I think it is a good way to introduce people to other CNC work. (nice and small).

I’ve kind of stalled on that project. The mechanical work (thanks, Dave!) and electronics (thanks, Lorin!) are complete, though untidy. A working software tool chain is the current holdup, which should in theory be my strong suit. I have some candidates, but haven’t yet assembled them.

Circuit layout and gerber generation is where I keep getting stuck. I don’t have a workflow for that piece, and with no immediate need for PCBs, nothing is driving me forward.

If anyone with basic KiCad experience wants to knock heads over the machine some evening, I might be able to rekindle some interest.

Regardless, the Shapeoko is not ideal for milling circuit boards, and that work should eventually be moved to a smaller and less expensive mill. It just doesn’t make sense to buy another machine until the software is proven out.

  • Ry

Jon Neal is the KiCAD expert. I can do eagle. I can get you test gerbers if you want.
-D

I have plans to do some experiments with bronze/brass engraving on the Shapeoko once it is back up in a useable condition. I’ll share/make a wiki when I do.