Milling Machine

Notatestpilot

Notatestpilot

Pre-takeoff checklist
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Notatestpilot
I'm posting this question to ask for suggestions on a good size milling machine.
There's a popular company that has a 4x16 metal mill for sale. I will also need a rotary table to accurately mill large radiis. But, what size?
I would use this mill to make fittings and brackets to upgrade secondary structure for my flying kit plane.
Thanks!
 
Notatestpilot said:
I'm posting this question to ask for suggestions on a good size milling machine.
There's a popular company that has a 4x16 metal mill for sale. I will also need a rotary table to accurately mill large radiis. But, what size?
I would use this mill to make fittings and brackets to upgrade secondary structure for my flying kit plane.
Thanks!
Click to expand...
Really depends on how big the parts are you want to make and what materials.
 
I didn't have a mill or a lathe while building. Then I got a Shoptask 3-in-1 after I was flying. I wish I had it while building! It's not a Bridgeport but so far it's done everything I've needed.
 
Notatestpilot said:
I'm posting this question to ask for suggestions on a good size milling machine.
There's a popular company that has a 4x16 metal mill for sale. I will also need a rotary table to accurately mill large radiis. But, what size?
I would use this mill to make fittings and brackets to upgrade secondary structure for my flying kit plane.
Thanks!
Click to expand...

I've been shopping for a long time, so no experience. But in true guy on the Internet fashion, I'll pop in with this: Rotary tables can be tall. Small mills don't always have a lot of Z clearance. So make sure you include the part height, tool length, collet or tool holder length, etc, and that you have enough room left over.
 
If you're machining steel you don't want to go too small or you'll have to work very slow. I have a Jet JMD-15 (Rong-Fu RF-30) which I used to make the fittings for my Starduster landing gear rebuild. I don't think I'd want anything smaller. It's not a proper Bridgeport but it gets the job done with some care. I bought it used with a bunch tooling. The general consensus is that for the Chinese machines the older Taiwan made ones are better than the newer mainland China ones. I added DROs and a variable speed DC drive (treadmill motor conversion) so I wouldn't have to shift the belts to change the speed. I also have a 6" Vertex rotary table, 4" seemed too small and 8" is too big.

Hobby-Machinist.com is a good resource.

upload_2021-12-18_17-44-10.jpeg
 
Anything short of a Bridgeport-style mill is often a waste of money. Small mills have too much flex, causing chatter and bit breakage, forcing you to cut very slowly, which results in work-hardening of the workpiece as the cuts are too shallow to get beneath the hard zone created by the previous edge. That burns out the cutters.

Been there, done it for years.
 
Where are you located? Around the northeast you can find Bridgeport mills for sale around a grand. I picked up a j head Bridgeport with a 12” rotary table not too long ago for $800. The mill is the cheap part. You will spend hundreds more on tooling.
 
I live in Saint Louis MO.
I plan on buying the 4x16 mill from Grizzly Industrial.
Thanks for all these good responses.
 
Dan Thomas said:
Anything short of a Bridgeport-style mill is often a waste of money. Small mills have too much flex, causing chatter and bit breakage, forcing you to cut very slowly, which results in work-hardening of the workpiece as the cuts are too shallow to get beneath the hard zone created by the previous edge. That burns out the cutters.

Been there, done it for years.
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This. Most of the inexpensive millers I've seen are drill presses with an xy table below. Good for wood and plastic, metals look like they would be a challenge.
 
Dana said:
Yes, but a lot of us don't have room for or can't afford a Bridgeport. We make do with what we have.
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Yep. I would love to have a Bridgeport and a Southbend or Clausing lathe. There's just not enough room in my shop. Most of the work I did was aluminum and the steel parts were small so my little machine did fine. Just make sure your tooling is sharp and don't spare the cutting fluid and you'll be fine.
 
For airplane parts mill drills are fine. If you have the room, used Bridgeport's are about the same cost as the smaller mill drills and you can sell them for what you bought them for.
 
The other problem with a "real" Bridgeport is moving it, they're heavy. Not something you're gonna carry down your basement steps...
 
Dana said:
The other problem with a "real" Bridgeport is moving it, they're heavy. Not something you're gonna carry down your basement steps...
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Yup. The will also easily remove your fingers while using them if you don't know what you are doing.
 
Dana said:
The other problem with a "real" Bridgeport is moving it, they're heavy. Not something you're gonna carry down your basement steps...
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Down a set of stairs is hard but if it's going in a garage or a walk out basement they are a piece if cake. I moved mine by rolling it on some 1" black pipe from home depot and using a trailer from uhaul. You need to flip the head and lower the table to get the cg low but once on the pipes you can push it around by hand. A pinch bar also helps to turn it in a different direction and get it up on the pipes. There are already notches in the foot of the base to get the pinch bar under. A Bridgeport really doesnt take up a whole lot more space in a shop than some of the bench top mill/drill a by the time you build a table to put the smaller machine on.
 
Notatestpilot said:
I live in Saint Louis MO.
I plan on buying the 4x16 mill from Grizzly Industrial.
Thanks for all these good responses.
Click to expand...
My son bought one of those. Even after I warned him. Now he has this:

upload_2021-12-19_10-56-48.png

The point is this: Don't buy a small, cheap machine and expect it to do anything but tiny work, and even then the finish will not be too good. That applies to mills, lathes, drill presses, whatever. You get what you pay for. I know that most of you won't have a hope of shoehorning anything like that into your basement and you'll have to get something a lot smaller, but heavier is stiffer, and stiffer is better.
 
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The hard part of moving these in was getting the Tormach PCNC-1100 mill through one of the doorways... (Had and engine hoist and a pallet jack) (lab at school, not my shop)
upload_2021-12-19_12-51-52.png
 
I’m close to you, I’m south in Cape Girardeau. I have the grizzly G0759 mill which is a 7x29 mill with dro. I’ve been happy with it for the small projects I’ve done with it.
 
:) If there's a theory that every POA thread devolves into a discussion of 1940's European politics, every discussion on mills always goes to "you should just by a bridgeport". Which makes perfect sense if you have a drive in workshop with either an overhead crane or a forklift.

You'll never make money as a machinist with a 350lb imported mill, but I know several people who use them successfully for making small parts out of aluminum, mild steel, and stainless.
 
Hmmm... mills being categorized by size in this context just really doesn’t make sense.

I think you’re just asking for advice on mills... From a machinists point of view, you really didn’t tell us your needs. As a home builder myself, I can make a fair assumption.

Airplane parts really don’t require much insofar as machine capability. And I’m guessing you don’t have a lot of experience machining, or formal training.

In my opinion, the lion’s share of machining is workholding and order of operations. So you need a crash course. This is fairly easily done by buying and reading a series of 6 small books authored by Dave Gingery. He’s a retired shop teacher who designed and built an entire set of machine tools, including casting his own parts, from scratch. I don’t recommend this...

But, reading and understanding how he did it, will put you YEARS ahead. He writes clearly and logically. You’ll understand the capabilities of all the machine shop tools and will then be well equipped to use what ever machine you acquire, effectively.

I would say a machine that operates well, and is fairly NOT slap worn out will probably be you’re best bet.

The classic import mill drill WILL suit your purpose, IF you know how to use it. However, learning the REAL capability of machines will allow you to use a horizontal mill for example, which will do EVERYTHING a vertical mill will do and more.

Search eBay for Nichols horizontal mills. They’re cheap, plentiful, American made, POWERFUL and dead rigid. Very few are worn out. Small, but HEAVY. Most are lever operated, but retrofitting a lead screw is easy if you read the Gingery books. It’s not necessary though.

https://www.ebay.com/itm/313734202856?hash=item490c0405e8:g:CeoAAOSwB4VhSdNg

The book set is less than $100, and worth a year of formal machinist training or more. “How to build a machine shop from scratch”.

https://www.amazon.com/Build-Your-M...ocphy=1018036&hvtargid=pla-762811232072&psc=1

Food for thought.
 
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This is a good take.

I've made a bunch of parts for my plane with my cheap, crappy, Chinese 3-in-1 machine. Every part came out just fine.

The people saying you should get or need a Bridgeport are the same ones who would tell you that you need Snap-On tools to put together a push lawnmower from Home Depot.

It's all about requirements, expectations and knowing how to use what you have.
 
And what’s more... Bridgeports ain’t all that...

I had a Wells Index 847, GREAT machine.
Have a Fray 10RH, Milwaukee 2HL Vert, Milwaukee 2D and something that dates pre Index 55 vert. All five of these machines cost $3,000 total.

Hard to find a reasonably priced b-port that’s not slap worn out.

I also run a Milwaukee 2H horiz that IS slap worn out. Still, taking its shortcomings into account, it’ll hold several tenths tolerance. It cost a whopping $50.00. At twice the weight of a b-port, it’s not without its own problems! No such thing as a free lunch.
 
One of the previous respondents said something about safety and losing fingers...
That caught my attention - so what safety cautions should be practiced while running a mill?
Please comment.
 
Honestly, work holding. It’s when things move or come loose, bad stuff happens.

otherwise common sense.

Cool little tidbit, always keep a cheap disposable paint/acid brush handy for removal of swarf. Rags are DANGEROUS as they get caught and wind up. Fingers, obvious. Little hooks, get caught and swing... compressed air exacerbates the eye protection issue and little hot chips wind up in your ear or down the collar of your shirt and more unsafe things happen. Little cheap paint brush, works awesome!

Also great for applying little dabs of cutting oil, which is all ya need in this context. Flood cooling is great, but probably not necessary.

Lots of light. Clear area around your feet. Keep clutter off the machine altogether.
 
It's a machine that spins sharp pieces of steel around around.

Same safety cautions that you would use around any piece of equipment which does that.
 
Albany Tom said:
:) If there's a theory that every POA thread devolves into a discussion of 1940's European politics, every discussion on mills always goes to "you should just by a bridgeport".
Click to expand...

There are people, plenty of them (relatively) that buy little cheap machines and then go buy the real thing once they get fed up with the serious limitations imposed by the little machine. I don't think there's anything wrong with pointing that out.

Bridgeport is a brand name. If you start searching for Bridgeports you will find big prices. There are many good Asian machines that perform just as well, especially if they're Taiwanese. Those folks have been doing this for a long time now. The generic name for that type of mill is "knee" mill or "vertical" mill.

Most cheap mills have a rectangular column that has a very small attachment at its base, introducing flex. The column is small enough to twist under load: you get chatter. The mill-drill types have a round column that has the same issues, but many of those are larger and heavier. and stiffer. For the guy that has the accessible room and the money to spare and the desire to really make stuff, bigger is better.

My lathe is a 12 x 24. I wish it had a longer bed, 36", but this one was what I could afford and could lift with an engine hoist and roll into the garage and was in really good condition, low hours, so I bought it. A lathe I had years ago was a Taiwanese machine, gear head, nice, accurate machine that I scooted though a basement window into my shop at the time. It weighed 1000 pounds. Strange things are possible. I made money with that one.
 
For aircraft work even harbor freight quality mills will be fine. Most of the time you are cutting aluminum, or plastic. If you are cutting steel it's usually pretty thin. Let's be honest, you aren't going to be machining your own spring gear legs unless you are really dedicated. My only issue with the OP's selection is the 4" Y travel. That is a serious limitation that would be a huge pain, I would have upgraded to the 6" version. You can find used full size machines though for the same price as one of the new small Grizzly ones if you have the room for it. Not to mention you can sell it for what you paid for it when you are done.
 
Dana said:
The other problem with a "real" Bridgeport is moving it, they're heavy. Not something you're gonna carry down your basement steps...
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Older round-overarm Bridgeports (which are the cheap ones) weigh just under 2,000 lbs. They do come apart, and many I've looked at had substantial wear (possibly ex-school shop units).
Some of the smaller square-column imports are pretty decent; check out Blondihacks channel to see one make all kinds of parts.
When I move into my retirement home next year, I'm gonna get the biggest, heaviest milling machine I can afford. And build an airplane.
 
Notatestpilot said:
One of the previous respondents said something about safety and losing fingers...
That caught my attention - so what safety cautions should be practiced while running a mill?
Please comment.
Click to expand...
You should probably take a class from a local community college or be very dedicated to learning what to do before jumping in and doing it. Mills and Lathes and and will draw you in, kill/maime you and keep on trucking without giving it a second thought. They are industrial pieces of machinery meant to be treated as such, it's a different animal than a run of the mill (pun intended) drill press.
 
Notatestpilot said:
One of the previous respondents said something about safety and losing fingers...
Click to expand...
The best way to have a finger removed is to wear cloth or leather gloves - once they snag on the cutter the result is somewhere between laceration and amputation.
Another good way is to be wearing rings.
Long hair or hoodie strings can /have resulted in injury and death.
Parts not held down well can "helicopter" - particularly sheet metal - to put an aviation spin on it...
Just think of it as helping your ER doc make his/her next yacht payment.
 
Notatestpilot said:
I am not buying a Bridgeport!
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If you dont want a Bridgeport at least get something a little better than that 4x16 mini mill. It isn't going to be capable of much with only 4" of Y travel and tooling is going to harder to find since the machine takes a MT3 instead of more standard R8 tooling. The way the vertical column bolts to turn base with just a single large bolt also makes it so the machine is not rigid at all. Maybe they changed it but the gears inside the head were also made out if a nylon plastic and tender to break. Those mills were meant for machining small plastic and aluminum. I would recommend looking for a used RF-30 or similar machine with a R8 spindle. They sell for about what that mini-mill goes for new.
 
kmacht said:
If you dont want a Bridgeport at least get something a little better than that 4x16 mini mill. It isn't going to be capable of much with only 4" of Y travel and tooling is going to harder to find since the machine takes a MT3 instead of more standard R8 tooling. The way the vertical column bolts to turn base with just a single large bolt also makes it so the machine is not rigid at all. Maybe they changed it but the gears inside the head were also made out if a nylon plastic and tender to break. Those mills were meant for machining small plastic and aluminum. I would recommend looking for a used RF-30 or similar machine with a R8 spindle. They sell for about what that mini-mill goes for new.
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Yup. My son's cheap lathe and mill gave him that sort of grief. Plastic gearing, skinny plastic drive belts more commonly seen on sewing machines. Toy tools.
 
Notatestpilot said:
I'm posting this question to ask for suggestions on a good size milling machine.
Click to expand...
Almost anything will work for that purpose. The least desirable mill to buy is one with a round vertical column, commonly called a mill/drill because it's just a drill press with a draw bar spindle and x-y table. Limited accuracy but it would work for your stated function. Get something that has an R8 spindle because that's the most common tooling.
 
Dan Thomas said:
My son bought one of those. Even after I warned him. Now he has this:

View attachment 102928

The point is this: Don't buy a small, cheap machine and expect it to do anything but tiny work, and even then the finish will not be too good. That applies to mills, lathes, drill presses, whatever. You get what you pay for. I know that most of you won't have a hope of shoehorning anything like that into your basement and you'll have to get something a lot smaller, but heavier is stiffer, and stiffer is better.
Click to expand...
That's what she said!;)
 
kmacht said:
Where are you located? Around the northeast you can find Bridgeport mills for sale around a grand. I picked up a j head Bridgeport with a 12” rotary table not too long ago for $800. The mill is the cheap part. You will spend hundreds more on tooling.
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Thats over a ton to move and level. Not something you do on a whim.

Also the mills are not the expensive part.it can cost you $500 simply to hold down your first part... Not to mention the micrometers youll be needed. And cutters and and and

Unless you have a use for a mill beyond a build, find a local shop for one off parts.
 
It's not the mills that'll cost you, it's the tooling that gets spendy.
 
I would have to say that there are plane builders and plane flyers. I would thoroughly enjoy the build process. Some EAB folks would rather farm it out and just plug and play…
To me that loses the true benefits of building an airplane; no gain of information nor education.
For instance, if while building my kit plane, I needed a bracket fabbed per blueprint. I make it by machining it with a mill, I gained the experience of learning to use a mill, that’s the satisfaction!
 
Chip Sylverne said:
It's not the mills that'll cost you, it's the tooling that gets spendy.
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It's not the airplane purchase that costs you, it's the maintenance and insurance and hangarage.

Like anything else, the devil is in the details. Homebuilders are frequently surprised when their projects end up costing four times as much as they planned. They didn't sit down and add in every little fitting and turnbuckle to the materials cost. That stuff adds up. Same with a mill or lathe; you have to budget for that tooling. AND YET: all that stuff is way cheaper than it was 40 years ago when I was doing it. Most of it is available from Asia, for a lot less than it used to cost. I have a Mitutoyo one-inch micrometer I bought in the late '80s; paid about $45, I think, in 1988 dollars, for it. I also have a one-inch Chinese micrometer that I paid maybe $12 for, and it's just as accurate. All my lathe tooling and other measuring tools are similarly inexpensive. This generation is able to afford far better stuff, and much more of it, than their fathers and grandfathers could. There is no reason to complain. The cheaper imported stuff might not be good enough for manufacturing stuff 40 hours a week, but it's much more than good enough for the amateur machinist. It's a lot better than his skills, anyway.
 
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