Machining SIG

#1

For those of you who were at the meeting last night and were interested in discussing how we can build out the machining area, here’s the place.

#2

This is a topic that I am personally interested in. Unfortunately, this category would be expensive to build out. Although manual machines can be used to make quite a lot of things, my experience has been that many people just aren’t anal retentive enough to make good parts on them. I suppose that if we could find ones that could be upgraded to CNC but which could still be used manually, that would be the best for a space like this.

I learned on manual equipment but have become more interested in CNC machines in the past decade because they can do things more precisely than I can, can do it faster, can make compound 3D shapes that I couldn’t by hand, and can make 100 of something as easily as one.

A minimum viable set of equipment for machining for me would include:
A mill with:
a set of collets
rotary table
right angle holder for the rotary table
things to hold down work pieces
Machinists vice

A lathe with:
three jaw chuck
four jaw chuck
Quick change tool holder
tail stock (not sure if this is standard or not
Boring bar

Grinding wheel
Drill press
Air compressor with blow nozzle
Brushes
cutting oil

I suppose that tooling and consumables should maybe be up to members to bring.

I’m probably forgetting a lot of things but that is what is coming to mind right now.

#3

Hi, This is Cord.
I absolutely agree with your list. Maybe some things like a rotary table would need to be benched for the first while, but should definitely be on the short-list of things to get.

The cost of getting a bigger knee mill/bridgeport style is justified. Having both cnc and manual on the same machine would be great. CNC does add to the cost, so might have to wait for the budget to catch up to our shopping list.

Any lathe you buy should come with a tail stock.
An effort should be made to get a lathe that has threading capabilities (both metric and standard, even if it means changing gearsets). Quickchange gearboxes are vastly better to have than gears that must be changed for each desired thread pitch.

I also agree that tooling and consumables should be member-brought, perhaps being able to convince the front desk to have one or two useful sized end mills on hand to buy, or to “rent” for a nominal fee, with a “you chip a flute, you buy it” policy. That would let newbies jump in to the field without having to try to navigate buying tooling they aren’t familiar with, but doesn’t have Protohaven footing the bill for every mistake.

I think things like the spare chuck, boring bars, flycutters, etc, should all be check-out items to help mitigate things growing legs and walking out of the shop.

We could pick up some used but decent machines from craigslist if we had a way to transport them. Do you know anyone with a low, drop-gate trailer?

#4

Later in the summer I will have access to a ten to twelve foot long trailer with four full-size wheels on it. I’m not sure what the weight rating is. I have a vehicle that can tow it.

#5

If you shop you can get a good deal. I got a South Bend 10RKL, delivered, for $2500. Not bad testing on an old workshop lathe:

#6

Here’s one on Craigslist right now:

https://pittsburgh.craigslist.org/tls/d/south-bend-lathe-ec-rebuilt/6537777975.html

I’m above my spousal approval limit or else I’d take a look at it.

#7

That one is in Columbus, Ohio, but it looks to be in good shape.
You said you’d have access to a trailer some time, right? I see lathes come up locally for quite a bit cheaper, but since I’m not superman, I have no way to move them. We need to form an elite squad of heavy-equipment movers that we can send out to collect good-but-cheap machines when they pop up.

#8

Just out of curiosity, where do you look to find used equipment? I’ve been watching Craigslist but would be interested to know of other places. Surely there must be a used machinery place around here but I’m not aware of it.

#9

Mostly just craigslist. Sometimes I run across an auction that has some things, but nothing regular.

#10

pittsburgh.craigslist.org
www.auctionzip.com
Facebook Marketplace

#11

I just found this on Craigslist. I’m used to fully manual or fully CNC. This seems to be a hybrid. The price is right I think. I’ve contacted the guy to take a look at it.

https://pittsburgh.craigslist.org/tls/d/vertical-milling-machine/6552092718.html

What does everyone think? I’ve never heard of the brand personally.

#12

Looks like they are selling on ebay for quite a lot more. This brings up the question: How much of a project are we willing to take on if a machine needs some work? Will there be funds in the near future to make repairs?

#13

This might not be a project. I heard back from the owner:

Hi Jack,
I bought a building and it came with it. To the best of my knowledge it works since the building and assets were a quick liquidation due to owner health problems. If you would like to see it run, let’s set up a time and you can start it up and inspect it. We are in the Bethel Park Industrial Park.

I got his number and will be calling him tomorrow. This brings up a few questions:

  • Do any of us have access to a forklift? This thing weighs 3040 pounds so it is a little more than I can heave into my minivan.
  • Do any of us have access to a trailer that can carry it?

This guy may have a forklift there so we may not need to transport a forklift as well as the mill if we get it.

What should I inspect on it? What I know to look for are backlash, and how hard it would be to fix it if it has a large amount. I’ll see if I can measure the runout on the spindle. I’d run the spindle up to speed and check that all axes work. I think that if all of that works then there is no point in looking a gift horse in the mouth.

#14

Grab it. You won’t be able to check for backlash, since there are no manual cranks for the x/y. Also, backlash shouldn’t matter on a strictly CNC machine since the physical position of the table is measured.
I don’t have a trailer, sadly. Would be worth renting one from U-Haul.

#15

I picked up that machine today. (I ate my Wheaties) The machine initially wasn’t connected to power but the company happened to have an electrician on staff who wasn’t at a job at the moment so they hooked up power for me. The mill’s computer powered right up and after a bit of head scratching, I managed to get all three axes to move end to end. Initially it was at the limit of one of the axes and was giving an error that wasn’t very clear about what it was for but once I cleared it, everything worked fine. I didn’t manage to spin up the spindle through computer control but could with the switch on the control panel. It ran in forward and reverse just fine. There was no tooling there so I couldn’t use my indicator to check things out with regard to squareness or table flatness. Other than a little surface rust around things that were sitting on the table and on part of the one of the cabinets, which could be repainted if we want to, everything looked good. I opened up the electronics compartment and everything looked really clean inside. There was a computer attached to the mill but it wouldn’t boot. I suspect that they wrote their programs a long time ago and loaded them into the computer inside of the mill and never needed to use the external computer again. The external computer connected to the mill via a serial port. I’ve used a mill like that before. Last time, it took me about a day and a half of pouring through user manuals to figure out how to externally control the mill but I succeeded and expect that I will be able to again.

If anyone has access to a forklift that we could borrow and use just to get it from a trailer up to the loading dock, that would be awesome. Listed weight is 3040 lbs but this one will be a bit heavier because of the CNC retrofit. I’ve seen accounts of people splitting these up to move them but I’d prefer to not have to do that.

#16

Awesome!
I don’t know anyone with a forklift … but it’s probably fairly important to keep the machine out of the weather. Is it a covered trailer? If not, I’m happy to lend whatever dismantling assistance I can, and can bring a pneumatic engine hoist to help awkwardly lift things around.

#17

One thing that I’m not terribly familiar with is collet holders and tool attachments for mills. The larger mills that I have used all used R8 collets. This mill uses something different. It uses a tool shaped something like a C with a little hook on one end and a straight handle on the other end to tighten a nut on the bottom of the spindle. Here is a picture that shows the tool sitting on the table:
https://drive.google.com/file/d/1yVsK49LXGi_gKpEYrIR1f7ScFh5NHqBH/view?usp=sharing

Here is a picture of the bottom of the spindle:
https://drive.google.com/file/d/1kGEQpN5IQNTxPHLBBBGYXZN5Lpt4u4Xq/view?usp=sharing

We’ll need to get a bit of tooling to use this mill. What sort of tool holder would go in here?

#18

I should clarify I guess. I paid for the mill today but haven’t actually taken possession of it yet. The previous owner said that he would like to see it be gone in the next two weeks.

#19

That’s a ‘hook spanner’ or ‘pin spanner’, hard to tell which from the picture. Everything I can find on the machine says it takes R8 collets, so that sleeve at the bottom of the spindle must rotate with a tube all the way up to the top of where it will meet the threads of the collet. That is a distinct advantage for tool changes since you don’t have to reach up to the top of the machine with a wrench. Might turn out to have disadvantages too (runout?), but I like the concept.

#20

So … maybe I’m a hoarder, but I just went and pulled six R8 collets out of a drawer in the garage, so we’ll at least be able to tell if that’s what it takes or not. Also have an R8 flycutter. Happy to loan what I have to the cause for the time-being.