Adjustable tool holder

[brebey]

I just recently finished building a Rockliff-like CNC router, and when I attempted to flatten my spoil board with a 3/4" straight bit, I learned immediately that my cutting tool (a Bosch trim router) is not square to the table.

My tool holder is simply a square block of wood with a tool-sized hole in the center, split in half. One half is screwed to the Z-axis base, the tool is set in the 1/2-circle, then the other 1/2 circled is screwed on to clamp the tool in place. This system has zero adjustment capability, save for shimming with paper, etc., which isn't very practical or efficient.

Does anyone have any ideas for a reasonably simple tool-holding system that can be adjusted in the x and y directions?

Thanks!

Bill

[joecnc2006]

The 1st thing that comes to mind is a double holder setup similar to the one on my model 2006, and make the center holes a little larger so you can shim it up on top ring or bottom ring which ever you need, with a single holder, the router will not have any adjustments.

Joe

[joecnc2006]

This is an interesting problem, maybe people can post on how they ensure the cutting tool is perpendicular to the X and Y Axis.

[multiplex]

I haven't quite conquered this yet with my build, but i may consider putting in a large fly cutter and measuring how parallel it is to the table using feeler gauges as i rotate it. the bigger the cutter, the better

hopefully there will be enough adjustment available in the body holes of the screws, and by adding shims.

[NEATman]

Bill-
Here's a concept that just came to mind:
Perhaps if you make a new wood ring, just as you have now, but make it with a smaller ID. Mount it in place on the Z axis. Then invert your router with the bit sticking up, level it's base to the XY plane of travel on your router with an indicator. Clamp your router to the table in this inverted position, and use it to enlarge the hole in the clamp by programming a circle.
Your router mount should now be perpindicular to both the X and Y travel by as accurately as you leveled the base of the router to the travel.

The best part is no adjustment is needed, and you won't need to qualify anything before hand.

NEATman

[joecnc2006]

Originally Posted by NEATman Bill- Here's a concept that just came to mind: Perhaps if you make a new wood ring, just as you have now, but make it with a smaller ID. Mount it in place on the Z axis. Then invert your router with the bit sticking up, level it's base to the XY plane of travel on your router with an indicator. Clamp your router to the table in this inverted position, and use it to enlarge the hole in the clamp by programming a circle. Your router mount should now be perpindicular to both the X and Y travel by as accurately as you leveled the base of the router to the travel. The best part is no adjustment is needed, and you won't need to qualify anything before hand. NEATman

most people will not have room under the z-axis for the length of the router tool for this to work.

[joecnc2006]

you can make a tool holder similar to the K2 holders and shim the holder at the bolt up mounting plate.

[brebey]

I've come up with a marginally usable solution to this problem, and it's incredible simple, so I thought I'd include it here.

Let me preface by saying that the only "good" solution to this problem allows for some sort of threaded micro-adjustment withOUT removing the cutting tool. The reality of simply removing and replacing the tool introduces error in and of itself. It's nearly impossible, barring highly-precise machined tools and holders, to re-resigister the tool in the holder in exactly the same orientation. I'm dealing with home-made a wood clamp and a Bosch trim router that's not designed for mounting - a scenario that might apply to a lot of us.

That said, here's my "NOT good" solution - requires removal of the cutting tool to make adjustments. I have, though, after some fiddling, gotten my router pretty close to square to the table. All I did was remove the face of the clamp and the cutting tool, and counter-sunk two sheet metal screws into the lower portion of the stationary part of the clamp, at about 10:30 and 1:30. I am now able to back out the two screws in very small, controlled, reasonably repeatable increments to adjust the squareness of the tool in both the x and y directions.

I've included a rough drawing of the arrangement. It's not good, and still variables such as the order in which I tighten the clamping screws, how much those screws are torqued, etc., all effect the alignment. It really helped me a lot, though. I hope someone else benefits from it.

The image is at: http://www.rebey.com/images/ToolClamp.png

[Rance]

brebey,

Clever idea. How bout using machine bolts that protrude through your block rather than sheet metal screws? Thread the holes after drilling them. Then add a double-nut arrangement on the outside to grab a hold of for 'adjusting'. Of course the attachment of the outer clamshell would need to be spring loaded. Maybe keep it closed using a rubber band arrangement.

Rance