Once upon a time I had to drill several thousand tiny holes to a specific depth and I was fairly certain I would have to change drill bits in the middle of the job. I call this gadget a Drill Depth Presetter. If you ever get into a situation where you have to drill more holes than can be done with one drill bit, or if you fear losing position if a bit change becomes necessary, this is the ticket.
I position this device on top of the workpiece and hang the foot over one side. The drill point nests in a conical pocket in the end of the foot. I rotate the face of the dial indicator, zeroing the gauge at the depth I need. When drills became dull (and they did...) I replaced them, cranked the z-axis of the mill up until the reading was again zero on the dial indicator and I was ready to go again. The same thing can be done with the knurled depth stop on a drill press, so the presetter isn't limited to a milling machine.
|Photo #1: Pressing down on a little horizontal "foot" at the right end of a rocking arm makes the opposite leg push up on the dial indicator probe to the left.
|Photo #2: To use it, simply do your set-up as usual, then when the depth stop is set, remove the workpiece and insert the Drill Depth Presetter. Position the point of the drill in the conical depression on the foot of the presetter (impossible to see on this image, but it's there!), then return the drill to the bottom of the holes you plan to make.
|Photo #3: Lock the quill and rotate the face of the dial indicator to zero (a lousy photo, but the face has indeed been rotated so the needle points to zero). Note that the foot's vertical support column is slotted. This lets me make adjustments below the table top (this is particularly useful on milling machine setups).
Finally, release the quill lock, remove the presetter and do the job. If you break a drill, replace the bit, insert the drill depth presetter and move your depth stop until the presetter's dial again reads zero and you're ready to get on with the job.
If you're too lazy to make your own click on over to my products page and you can buy one.
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