Is this a vertical mill job?

I've been fabricating furniture and the odd handrail, etc for a few years now. I don't have any experience with a mill or lathe and so don't have a very specific idea of what I could do with one. I'm tempted to get a mill because I have a few applications where, if it served my purpose, I think it could justify itself in fairly short order.

I make a fair number of these cube coffee table bases like in the photo, from 5/8" cold rolled square rod. The glass is just resting on top of the frame. I'd like to inset the glass, but I don't like welding in tabs as it takes away from the clean look. Do you think it would be possible to mill out a corner along the entire length of my pieces of rod that make up the top, removing maybe 1/8" x 1/8"? I'd be effectively creating 5/8" angle in 1/2" thickness, so there would be an inset "tray" sort of for the glass to drop into. Hope that makes sense.

Anyway, I'm not sure if you can process entire lengths of rod like that with a Bridgeport-type mill, or if you can what power/travel specs you'd look for to ensure that it would do it smoothly. I'm sure if I get a mill I'd immediately not be able to imagine how I got by without it, but it's nice when you're scraping together the cash to buy something, to know how it's going to make it worthwhile.

Thanks for the help!

Yes, you could create a milled pocket to recess the glass. Keep in mind cold rolled stock has much residual stress and will move when you mill it. Expect it to curve to the milled side, a 1/2" curvature in a 50" piece wouldn't surprise me at all. Straightening is possible but adds another step and learning curve. The length required may require repositioning the workpiece.

Hot rolled typically doesn't move much but the rougher surface texture would probably be undesirable.

Don't get hung up on verticals. It could be done just as easy on a horizontal mill.

What gbent said. My first thought was a horizontal mill. Not that a vertical wouldn't work, but a horizontal milling cutter is better suited for that application, IMO. I'd be looking for an old K&T with a vertical head, so you've got the flexibility to convert it if the need arises.

Stress relieving/flame straightening is probably in the cards, too.

So you want to cut a square seating on you small square rods for your glass to drop into,yes a vertical mill would suit your needs and have other uses such as drilling and boring for you.I would have a look at your design as it seems to be creating a lot of work for its use.As cutting your seating is feasible but putting the thing together then dropping your glass into what then will be an internal square wont be as easy as it sounds

To add to what Onecut said, squareness of the assembly will acquire a whole new significance.

If I read the op's original correctly, he is only going to remove a 1/8 wide by 1/8 deep edge from the stock. I don't think this will warp nearly as much as some are predicting.

If you want to create a lip to support the glass you might consider bolting a continuous strip of flat bar to the underside of the square--a fastener every 8"-10" or so should be close enough. This will involve some work for sure but it will still be less than machining a corner out of the square. The machining itself will be tricky enough but the warpage is what's going to kill you. You don't like the idea of welding on clips but how about bolting them on? You could make up some pretty neat ones out of different materials--SS, alum. or brass, for example. The contrasting colours and textures would enhance the look of the frame...

Thanks for the input! These K&T machines look to be beasts. This one looks cheap- going rate is around 4k, right? Having looked at Bridgeports, I expected to be dealing with a 1-ton machine or more, but I saw a weight on one of these that was pushing 10k lbs!

What's the downside of using a horizontal mill with a vertical head on it? I expect generally I'd do a fair bit of simple hole and slot making- any reason this would be limiting?

I wondered about the warpage on these frames. I could use hot rolled and sand them- the only reason I use cold rolled is because the mill scale pops in the powdercoater's oven. I also have a tubing roller and maybe could correct some bend with it- flame straightening sounds like a can of worms I don't want to open. These tables are sort of a get in, get out situation.

fivefork said:

Thanks for the input! These K&T machines look to be beasts. This one looks cheap- going rate is around 4k, right? Having looked at Bridgeports, I expected to be dealing with a 1-ton machine or more, but I saw a weight on one of these that was pushing 10k lbs!

What's the downside of using a horizontal mill with a vertical head on it? I expect generally I'd do a fair bit of simple hole and slot making- any reason this would be limiting?

I wondered about the warpage on these frames. I could use hot rolled and sand them- the only reason I use cold rolled is because the mill scale pops in the powdercoater's oven. I also have a tubing roller and maybe could correct some bend with it- flame straightening sounds like a can of worms I don't want to open. These tables are sort of a get in, get out situation.

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Really depends on your location - Machines seem to be cheaper on the East Coast - I see Bridgeports all day on eBay/Craigslist for under $1500. Out here in Washington, it seems like the base line pricing for a worn out J-head is $2500-$3000, and that's assuming it's been sitting in a damp basement in Seattle for the past ten years, and you've got to move it up three flights of stairs and through someone's living room to get it out, because the garage door was replaced with a wall. Oh yeah, not under power, either. And no tooling. And the legality of the sale is questionable, because the guy that owned it died and it may or may not be kosher for the twice-removed cousin to be listing it while the estate is locked in escrow. So it'd be nice if you could move it at night, tomorrow.

Anyway. Yeah, most of the K&Ts are in a different league, weight wise. If you can move them without killing yourself or your bank account, that weight comes in handy in the form of increased rigidity. Consider the fact most Bridgeport style machines max out at around 2 HP. That 3CH you posted is rocking a 7.5HP motor.

I think the main downsides you're going to see are in the costs associated with ownership - 40/50 taper tooling is more expensive than R8, moving it is going to be pricey, it's going to take up a lot of floor space, and while most machines have a great user community behind them, it's not like the Bridgeport style machines - Spare parts, etc., aren't going to be as plentiful. Checkout Adam Booth's (abom79) Youtube channel - He's put together quite a few videos of his 307 S-12, doing both horizontal and vertical work.

Ever try a vinegar bath to dissolve hot roll scale? Works a treat, and saves me quite a bit of cash on the cost of abrasives - Flap wheels wear out fast digging through thick mill scale.

Re: straightening. All really depends on what kind of tolerances you're trying to hit, and what kind of work holding you've got - Glass isn't exactly ductile. I know if I was building those on one of my Certiflat tables, I'd want maybe 3/32"-1/8" clearance around the whole perimeter to account for the square bar bowing inwards from welding and the thing pulling a parallelogram on me - The material's going to be even less straight after machining it down into a fat piece of angle, which won't help the cause.

Another thought - Have a hollow rectangle plasma/laser cut out of 1/8" plate, with holes along the perimeter so you can plug weld it. Use rectangle instead of square bar for the top, It'd be questionably easier to keep everything square, autogenous TIG around the seam, good to go. Not saying it would be any quicker, just a different angle on the problem.

I can be done, and would work fine .. re: process you will likely need to adjust several times in the beginning.
I would maybe add an insert, as a flat- milled support, for the inside ledge.
Industrial epoxy.

No learning, dirt cheap in capital costs, no investment.
Zero distortion.
Invisible seam.
Much stronger than you probably think.

A great epoxy might support 100.000 kg on 5 cm x 120 cm x 2 + 50 cm x 5 cm x 2 = 1700 cm2 x 1000 kgf/cm2 = 1.7 m kgs.
3478 for example.
Generis at 1/10 the cost.
Too expensive, too good, but any basic garden variety industrial epoxy would work fine.

Re: used mill
When I see a paint job like that I get suspicious.

Expect it to bow and its going to bow in both directions if you mill it too. Glass is flat, any bows going to be really significant and need just as much straightening! I would esaily expect over 1" of bow in a 4' length, but its going to vary from one batch of metal to the next too.

A bridgeport will remove that 1/8" x 1/8" just as fast as a horizontal, your going to run out of feed speed before you can max out a cutter with even a couple of HP driving it doing that. Biggest agro is how long its going to take you to load - unload the mill.

the big horizontals are awesome power and rigidity.... great for heavy slab milling and slotting,
drilling huge holes . they are also made for large cutters(slow top rpm) and use heavy arbors and
stub holders = slow setup times and forget spinning anything smaller than a 1/2 hss endmill .

they also don't drill and tap(no quill) , and the spindle doesn't angle (unless you get a universal
table , or vertical head attachment ) , and they weigh ~ 10,000 lbs, so they're a bitch to move.

get a damned turret mill(bpt) with a DRO . if you only have one milling machine, it's the one to have
(like schaeffer beer) you will be amazed how agile they are to use and setup, and having a DRO will
make you wonder how you ever worked without one.


the job you describe could be done on a $500 JET mill/drill

adama said:

A bridgeport will remove that 1/8" x 1/8" just as fast as a horizontal, your going to run out of feed speed before you can max out a cutter with even a couple of HP driving it doing that. Biggest agro is how long its going to take you to load - unload the mill.

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My thinking with the horizontal was ganging up multiple 1/8" milling cutters on the arbor and slamming out a bunch of lengths at a once. As long as the arbor/spacers/milling cutters were in decent shape, and he put some thought into the jig, he should be able to maintain a sane tolerance.

fivefork said:

What's the downside of using a horizontal mill with a vertical head on it? I expect generally I'd do a fair bit of simple hole and slot making- any reason this would be limiting?

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The biggest down side of my B&S #2 Heavy's vertical head attachment is the lack of a quill. All movement into the cutter has to be via moving the table up and down. On most jobs it's not a problem because my table has power movement on all three axis. Where I really miss the quill is when trying to drill and tap holes.

That's why I also have a Manual Bridgeport For those times I need the quill.

If I were tackling your job I would put it on the horizontal and gang up 4 "saw blades" so I could cut 4 slots at once. That's the beauty of a big horizontal mill, it lets you use all types of cutters and has enough power to make many cuts at the same time.

Thanks for all the input. I'm thinking the point tnmgcarbide made above is on point. The big horizontals seem awesome, but I'm not able to do any of the rigging myself, and I'm space limited so a smaller do-all type machine is what I need. I have a real chintzy small drill press, so something that I could do a lot of holemaking and slotting with would be great. I'm running a small one-off kind of operation here, so being able to run multiple cutters at once is a lower priority.

I appreciate the other info in here as well- epoxy recommendation, vinegar bath etc will be good to try out.

If your not in a hurry just put 2 jobs back to back and go thro the middle with a 1/4ins cutter-2 in the time it takes to do one-And only one tool required

I don't know how many of these tables you make, but you should look into getting a custom profile from the mill. Expect to pay a tooling charge along with a minimum purchase. It is entirely possible you could throw out 3/4 of the material and still be money ahead over milling the rabbet. And with the one time tooling cost imitators may be scared out of the market, giving your tables a unique look.

GENERAL SPECIFICATIONS
*AS-IS
Very nice machine with nothing wrong can make good parts for years..Not seeing it run can be a $2,000 mistake for lost time and machine parts and repairs.
Have you seen it run?
Is anything wrong with it?
Can you put it under power and I will bring a mill hand to look it over.

I'd like to pile on the thought below - can you change the material? If so, it sounds to me like an aluminum extrusion with the desired profile might be the solution. I am presuming this is a low volume product. Its been a decade or more since I had a similar extrusion die made - seems the cost then was about $10K for the die. A closed section extrusion die is a fair amount more in cost than an open cross section.

gbent said:

I don't know how many of these tables you make, but you should look into getting a custom profile from the mill. Expect to pay a tooling charge along with a minimum purchase. It is entirely possible you could throw out 3/4 of the material and still be money ahead over milling the rabbet. And with the one time tooling cost imitators may be scared out of the market, giving your tables a unique look.

Click to expand...

aribert said:

I'd like to pile on the thought below - can you change the material? If so, it sounds to me like an aluminum extrusion with the desired profile might be the solution. I am presuming this is a low volume product. Its been a decade or more since I had a similar extrusion die made - seems the cost then was about $10K for the die. A closed section extrusion die is a fair amount more in cost than an open cross section.

Click to expand...

Last spring @ work I had a couple extrusions quoted - One had two closed cavities (think two triangles stacked on top of each other). About $1400 for the die, and $1.10/lb for the finished product in 1000lb quantities (3000 linear feet) - 6063 T6). This was Superior Metal Shapes out of CA.