Work holding ideas for a granite bed router

[kb58]

Well that's done, and something I don't want to do again. That little pile of granite "droppings", and a bigger pile of rock dust, is the result of boring through 58" inches of granite. Three diamond core drills gave their lives for this. The router drilled half the holes the holes but I had to manually drill the ones around the outside edges. Next is drilling aluminum tool plate to match, then adding threaded holes to that. Like a very expensive layer cake, hah.

[suntravel]

Looks good. I would threadmill the next layer of cake

Uwe

[kb58]

One small issue is making the holes in the plate match those in the granite. Diamond core drills are notorious for drifting laterally, thanks to the cutting surface being slightly bigger than the metal collar it's attached to. That's not so much a problem with the router-drilled holes, but it is with the hand-drilled ones. Since the hold-down bolt holes are non-critical, an easy way might be to go "medieval" and find the hole centers by punching through a piece of paper or cardboard, then transfer that to the top of the fixture plate - at least for the holes around the perimeter. They're going to be over-sized anyway, so that seems okay.

A related question: should the threaded holes in the fixture plate be blind or through holes? I ask because I expect some holes to get packed with chips and possibly coolant. The advantage of blind holes is that it can't work it's way down to the granite and possibly between the two. The downside is that it makes threaded less convenient.

[suntravel]

Blind holes and thread milling, super easy with intercon



Uwe

[kb58]

Understood. My point was whether drilling entirely through the fixture plate is a good idea or not, since chips and coolant could get down between the plate and the granite. Whether that's an actual concern, I don't know, hence my question.

[suntravel]

With through holes, you will have coolant under the plate, not good if you have this growing for a long time...

Uwe

[kb58]

Yes that was my thinking as well.

[EastMemphis]

What do you plan on making with this CNC? What is going to require coolant?

[kb58]

My answer is: When the laser was first invented, someone asked, "what good is it?" and the inventors said "What good is a newborn child."

To answer your question, other than the strong goal of being able to machine aluminum, I don't know! I enjoy building things and after selling off my cars, needed a new diversion. What I would like to do is sell niche products online, what they might be I haven't a clue. I see no point in watching YT vidoes about how to make $$$$ with a router, because everyone copies everyone else. The stuff I make will have to be unique.

But before all that happens, there's a lot of practical things to make such as fixture plates, low profile vice pieces, dust shoe, mist cooler, and it will contribute to the next project, a 2x72 belt grinder.

[tblough]

Metalworking is a recursive hobby.