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Holes in the end of large plates

legacymachining

Plastic
Joined
Mar 12, 2019
Hi Guys,

Question, how would you drill holes in the ends of long plates? For example, picture a fixture plate that is 1/2" x 12" x 24". It calls out holes on the 1/2" face with a pretty tight position tolerance. Im assuming maybe a manual mill? We are a full CNC shop at the moment.
 
Are you wanting to gundrill ?

We have gundrilling specialty shops around that doo mold bases and such.

Might want to look around for one in your local.
 
Hi Guys,

Question, how would you drill holes in the ends of long plates? For example, picture a fixture plate that is 1/2" x 12" x 24". It calls out holes on the 1/2" face with a pretty tight position tolerance. Im assuming maybe a manual mill? We are a full CNC shop at the moment.


On a plate that size and larger, we would use our horizontal boring mill, circa 1911. Smaller than that would be in the big VMC.
 
Funny haven't been in a shop without 'a' manual bridgeport, or at least one with a prototrak

Suppose a CAT right angle head used is cheaper than a bridgeport
 
Hang it off the table on a Bridgeport.
Farm it out.
Or buy a mill that has that capacity.



That about sums it up...BUT

On some CNC Vertical milling machines the spindle will go past the table edge OR the table goes past the spindle depending on how you look at it. On some of my Haas machine the spindle goes about an inch past the table. So I toss up an angle plate then hang and clamp a plate off table in the back by a few inches. That allows me to do some machine work, holes etc on the sides or ends of some plates.
 
If the hole is shallow enough, I'd hang the plate off the side of the table in the VMC. Otherwise an angle plate on the drill press.
 
Clamp on drill fixture with hardened drill bushings, works well in some situations, depends on qty / Tol. ...etc
 
I usually go down to my neighbor's shop and use his Bridgeport... he doesn't charge me anything, but I have to put up with his bullshit about how the "fancy" CNC shop can't do simple manual work. Then again, he also pisses and moans about being broke all the time :)

I don't want to acknowledge my own stupidity (at this point it would be a bit redundant anyhows), but the last time I needed to do holes on the end of long plate, I fixtured the plates on the cross slide of my lathe and put the cutting tools in the three jaw chuck. Worked slicker than shit. Set the Z using the fixture, Y using the cross slide, and drilled using the carriage (using what would be mill coordinate system kinda sorta...). Setup wasn't much worse than racking the head and putting an angle plate on a Bridgeport and I think it was quicker to run. White trash horizontal boring mill.
 
Man, some cool ideas, especially the lathe idea. I think for the volume and variation in work size i can make it work with maybe a good right angle plate on the machine table. Then use the through holes in the plate to bolt it to the angle plate?
 
I keep an old horizontal around for work like this. That being said, you didn't specify HOW tight the tolerance was?

I also keep an old drill press around for some things like this as well. From the base to the spindle is 40". I wouldn't use this for anything I would consider precision or tight tolerance.

G00 Proto, that isn't white trash at all, just good use of your tools. I think its funny now days everyone things lathes are only for turning round things. There are a lot of "common sense" uses for machines that have been "forgotten". My old south bend, that I just hated to get rid of, was made with 4 T-slots on the carriage, the top of the carriage was machined so that you could bolt anything to it and bore a hole.
 
This is a joke right?

I doubt it. The last shop I worked at had no way to square up plates, or put holes in the sides.

There are LOTS of shops I have been to that completely lack basic tools.... but they got lots of fancy CNC's!

This model works great if all you do is production and all of your parts fit in that envelope.
 
Don't neglect the value of building a drill jig with precisely located drill bushings and locators to control hole location, and then using a cheap&sloppy drill press with an angle plate on the table or base to control hole axis parallelism. If the plates were long enough, I might do that even though I have a horizontal mill. Of course, if they are too long to fit under the drill press spindle, there's no choice but to hang them off the mill table with an outboard support.
 








 
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