Additional Drilling Equipment - ATLAS COPCO DRILLING BIT 103-5089-42-24, 49-20 SECOROC 90510843. 3-1/2" head diam, 5-1/4" length, 1" screw thread ID 2" OD. This is from my father's estate, I don't know a lot about it. It appears to be new, there are scuffs on the paint. I would think it would exhibit a lot more scuffing and have the sticker scratched off the side if it had been used before drilling through rocks. Look over pictures however and judge for yourself. This bit measures 5.5" and weighs 5.6lbs. Location: Las Vegas, Nevada. For complete listing information please select the Click To Bid button to see this item on eBay.