CarveSmart Stop Pin Drill
**PLEASE SHARE WITH ANY CARVESMART USER THAT YOU KNOW! **
I'm super excited to partner with my friends at AB Tools Inc. on this one! We all know time is money, whether you are a job shop or a solo act. Start saving now.
I'm a huge fan of CarveSmart soft jaws, but I'm always annoyed with the inefficiency of setting stop pins because I need 4 tools (spot drill, drill, reamer, chamfer) to get the job done. Normally this means taking up 4 tool pockets in the CNC and/or having to set up 4 tools if you can't afford to leave them in the machine. Sometimes I just need to put in one pin and it's not worth it. Enter the Stop Pin Drill! You can even drill holes "off line" on your Bridgeport instead of taking up time on the CNC. Yes, I actually tried it.
I emailed my concept to AB, they offered some suggestions, and I ordered a few prototypes to test for this project. The results exceeded my expectations and I'm excited to share this with my fellow CarveSmart nerds.
This tool is a prototype and no warranties or guarantees are implied. I received and tested a number of sample drills in 6061 aluminum. I have no idea how these will perform (if at all) in other materials. We took a plate and drilled 96 holes. Then dowel pins were inserted in holes #1 and #96 to test and compare the hole fit. #nailed-it
The microscope image above shows the tool after making the 96 holes with no significant wear. Sorry about the image quality. My scope has a very narrow depth of field and I was holding my phone camera up to the eyepiece ;)
It should go without saying, use a rigid tool holder since we are trying to spot and drill in a single plunge. A low mass/less rigid tool holder will allow more flex/vibration and produce poor results.
* 3/8" shank for rigidity
* 118* point angle
FEEDS AND SPEEDS FOR ALUMINUM
I'm no expert, but we used the following (conservative) feeds and speeds for testing. My goal was hole accuracy and tool life, not speed. Please bear in mind, we are going for a hole that is closer to reamed rather than drilled. No point in going bonkers for a couple of holes. The settings below are just suggestions. You should use your best judgement for the equipment and cutting conditions available to you.
- RPM: 5000
- IPM: 15
- FPT(IPR): .0015(.003)
- DWELL: 36ms (3 spindle rotations @5K RPM)
drill point angle118*
where it's made