squaring up large plates

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JimGlass
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squaring up large plates

Post by JimGlass » Wed Mar 24, 2004 10:27 pm

Came up with this jig/fixture for squaring up large plates of steel 3/16 thick. My mill is a JET 9 x 42. One plate was 21 x 38. Had to move the plate and machine the 38" side in 2 passes.

The outriggers (for lack of a better term) were made from extruded aluminum (80-20) 1" x 2" rectangle. Made special T nuts for the front of the Mill table to attach the aluminum extrusions.

Thought this maybe of interest.

Image
Notice the homade power feed??

Image
Notice the diagonal brace holding the extruded aluminum square to the table. Gage stops attached to the aluminum for squaring the plates.
Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

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Patenteux47
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Re: squaring up large plates

Post by Patenteux47 » Wed Mar 24, 2004 11:36 pm

Very innovative!!! What are the plates for?

Nice clean shop BTW.

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Andypullen
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Re: squaring up large plates

Post by Andypullen » Thu Mar 25, 2004 9:58 am

Hi Jim,

Your spindle is out WAY too far for that kind of work. I was shown when I started out that milling with the spindle out like that was the same as trying to carry a mill vise with your arms outstretched 90 degrees to your body.

Interesting approach to the problem, though.

Andy Pullen
Clausing 10x24, Sheldon 12" shaper, ProtoTrak AGE-2 control cnc on a BP clone, Reed Prentice 14" x 30", Sanford MG 610 surface grinder, Kalamazoo 610 bandsaw, Hardinge HSL speed lathe, Hardinge HC chucker, Kearney and Trecker #2K plain horizontal mill.

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JimGlass
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Re: squaring up large plates

Post by JimGlass » Thu Mar 25, 2004 10:32 am

Hi Andy:

Your right about the quil being extended. However, the endmill is 1/2" and I'm taking fairly light cuts and slow feed rate. The cutting area is relatively small. You would never see me run a large endmill like 3/4 or 1" with the quil extended like that particulary when taking any sort of a heavy cut. In fact, I almost never take heavy cuts. Your thinking changes when you buy your own machines. I baby all my machines. I don't want to replace them.

What are the plates for. Customer wants them squared up??? He bought the steel 1/4" oversized??? I do not know why. When square, I'll mount a number of air regulators onto the plates. It is all for machine controlls. I have learned when to ask questions and when not to!!!!!
Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

D_R
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Re: squaring up large plates

Post by D_R » Thu Mar 25, 2004 11:43 am

Jim,

Nice setup, but how much do you think you'll have to bill the customer?

I hate these kind of jobs. Presumably if your customer had ordered the material sheared to correct size that would have met his needs. Now you have to add bucks to his job cost which never seems to make customers happy even though it's his fault.

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Re: squaring up large plates

Post by Harold_V » Thu Mar 25, 2004 2:48 pm

Presumably if your customer had ordered the material sheared to correct size that would have met his needs. Now you have to add bucks to his job cost which never seems to make customers happy even though it's his fault.

The customer may just be the smartest one. If you're worked with shorn material very much you know that the shearing action leaves a rolled edge that is loaded with stress. Narrow shorn strips wind up like a spring. Whether necessary or not for the proper operation of the base plate, the buyer may want the edges clean and free of stress, with sharp corners. The only reason I'm suggesting this likely "goofy" idea is that I'm inclined to do the same thing (mill the edges), and by choice. [img]/ubb/images/graemlins/blush.gif"%20alt="[/img]

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

Harold_V
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Re: squaring up large plates

Post by Harold_V » Thu Mar 25, 2004 3:01 pm

Hi Jim,

Nice setup! Sort of brings to mind the backstop setup on a shear. I've faced that problem on countless occasions, but have always just resorted to measuring from the front of the mill table to the edge of a part with one of my trusty scales, which I have up to 24". The negative of that choice is that it's subject to error. You could go out of your way far enough to dial in your locating edge for that special time when you must be closer than a few thou.

While you can be proud of your creative thinking with the outrigger support, I'm of the opinion you have something much nicer in the picture. Your home brew power feed is most interesting. If you haven't told us about it before (maybe I missed it), I'd enjoy hearing how you went about building it. I recall paying a huge price for an added feed years ago when I bought a Servo for my first Bridgeport.

Always a pleasure to see your work, Jim. You have to be one of the most creative guys I've ever "known".

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

D_R
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Re: squaring up large plates

Post by D_R » Thu Mar 25, 2004 5:23 pm

"The customer may just be the smartest one. If you're worked with shorn material very much you know that the shearing action leaves a rolled edge that is loaded with stress. Narrow shorn strips wind up like a spring. Whether necessary or not for the proper operation of the base plate, the buyer may want the edges clean and free of stress, with sharp corners. The only reason I'm suggesting this likely "goofy" idea is that I'm inclined to do the same thing (mill the edges), and by choice."

Jim said the plate is to mount air regulators and part of a machine control. Sounds to me like a sheared edge would be just fine. Possibly a little grinding to soften the rolled edge. Certainly would be more cost effective than the setup Jim made to mill the edges.

Maybe this is a government job where cost is no object. Or maybe a purchasing agent who is not knowledgeable.

I had a goofy situation with a purchasing agent recently. The job involved milling angular ends at very odd angles on some 5/8" square bar. The parts were for an expensive art deco railing. The drawing showed the parts at exact lengths so the welder could put them together with little or no fitting. Simple job on the CNC and more accurate than trying to do them on a cold saw. Everything is cool until the PO instructs me to make the parts 1/8" over length "just in case". Needless to say the welder went ballistic when he saw this. All I could do was throw up my hands and say I did what I was told, sorry.

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JimGlass
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Re: Home brew power feed

Post by JimGlass » Thu Mar 25, 2004 7:01 pm

The power feed you see in the pic is a 1/10th hp, 90-volt DC gearmotor salvaged from where I work. At work these run 24 hours a day, 6 days a week. When the brushes wear out they toss the motor and install a new one. I grab them from the dumpster, turn the armatures and install new brushes. I'm running several of them and never had a problem with a rebuilt motor.

Image
As you can see in the pic, I'm using a timing belt to transferre power. I slip the belt off the pulleys when the powerfeed is not used. Put the belt on when I need the feed. Found a double pole, double through switch to make it reversable. It works quite well and I have no plans of replacing it.

Looks like $75 to square up each plate.
Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

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John_Stevenson
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Re: Home brew power feed

Post by John_Stevenson » Thu Mar 25, 2004 8:10 pm

Jim,
Chuck the supplied plates away.
Get some laser cut to size and square, 21" x 38" in 3/16" should work out at about 8.00 to 10.00 UKP each.
Pocket the difference in money and time.

John S.

Harold_V
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Re: squaring up large plates

Post by Harold_V » Fri Mar 26, 2004 12:12 am

Jim said the plate is to mount air regulators and part of a machine control. Sounds to me like a sheared edge would be just fine. Possibly a little grinding to soften the rolled edge.

You'll not get an argument out of me in that regard. To one that has no idea what the other person may or may not be thinking, it's just difficult to understand what, to them, is acceptable. Could be it has to go within a framework with limited clearances, or perhaps must be relatively flat. We could second guess it all day long and not come close, but one thing I know is if the person for whom it is intended is quality minded, when work comes up, Jim is the first one they're going to think of. I've yet to run into anyone that knows anything about machining that isn't impressed with work well done. Whether needed or not, machined edges are a sign of a quality craftsman. I won't go into the economics of achieving the machining, that's not my point. In the right industries, such features can spell the difference between success and failure for one seeking work. If Jim is willing to spend the time necessary to put out that kind of quality, he's the guy that's going to see work when the hackers are hungry. I firmly believe Jim is of such a nature. His shop reflects it. That's the cheapest advertising a small shop can buy. It worked flawlessly for me for 16 years.

Certainly would be more cost effective than the setup Jim made to mill the edges

Considering what I had to say above, and the fact that he now has the setup for future use, it could be one of the more ecconomical setups he's made.

Maybe this is a government job where cost is no object. Or maybe a purchasing agent who is not knowledgeable.

If it is a required cut, it's hard to say from where it comes. Most generally it would be directly from the print, or the project engineer. In the industry from where I came, purchasing agents had no authority to modify anything in regards to parts, although they had full reign over the order in regards to pricing and delivery. They were not permitted to act as engineers. It stands to reason that smaller, or different businesses might have different operating methods.

I had a goofy situation with a purchasing agent recently. The job involved milling angular ends at very odd angles on some 5/8" square bar. The parts were for an expensive art deco railing. The drawing showed the parts at exact lengths so the welder could put them together with little or no fitting. Simple job on the CNC and more accurate than trying to do them on a cold saw. Everything is cool until the PO instructs me to make the parts 1/8" over length "just in case". Needless to say the welder went ballistic when he saw this. All I could do was throw up my hands and say I did what I was told, sorry.

Definitely a case of the left hand not knowing what the right hand was doing. Their business policy is in need of scrutiny. To avoid such problems, large shops where work is on a recurring basis, such as a fixed product, have travelers with operation sheets that specify any variations from the print, plus sequential operations. Companies that large usually have a methods department where the processes are organized. That way you don't find that your elements are 1/8" too long because someone along the way thought they'd toss in their ill-conceived decisions.

There's a lot said about the cost of defense work, but give them one thing. For the most part, the items work. That they succeed is in no small part a direct reflection on the high standards that are enforced in the (defense) manufacturing industries. None of that comes cheaply, and may, indeed, include milling the edges of a panel when a shorn edge might have served. It's a matter of keeping the bar high instead of lowering it. Even when it may appear it doesn't matter.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

D_R
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Re: squaring up large plates

Post by D_R » Fri Mar 26, 2004 2:10 am

Harold,

I guess we aren't too far off in our opinions here.

As I said earlier, I hate these kind of situations. Jim may or may not get customer praise for his work here. There's no doubt we're praising it here. Where the problems can come in is if some mucky-muck up the food chain looks at the the charges for Jim's work and asks why he didn't inform them of the costs and use a less expensive solution like John S suggested.

I've been burned in these type deals. I make it a point not to criticise customer's decisions and thought processes, I do try to tactfully suggest an alternate less expensive approach if I see it. I've been in the business 20+ years and found that customers appreciate the suggestions, whether they take them or not is their decision.

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