TIG Welding HSS Drill bits to Stainless

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We have been welding Drill tips to Stainless tubes for awhile now but can't stop a small percentage of them from cracking, can you help with filler suggestions or technique advise?0.250" OD drill bit tips 0.125"deep shoulder fits into tube0.250" OD tube0.080" wall tubeTIG butt weld currently with no fillertried preheating all parts to 200° and also cooling in vermiculite to control cracks but no lock getting to 100% success.Thanks for any help...Lamont
Reply:Originally Posted by LamontWe have been welding Drill tips to Stainless tubes for awhile now but can't stop a small percentage of them from cracking, can you help with filler suggestions or technique advise?0.250" OD drill bit tips 0.125"deep shoulder fits into tube0.250" OD tube0.080" wall tubeTIG butt weld currently with no fillertried preheating all parts to 200° and also cooling in vermiculite to control cracks but no lock getting to 100% success.Thanks for any help...Lamont
Reply:Yikes - no filler? I agree, try the 309/309L.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Thanks,We have thought about 309/309L but wondered if there was anything better? We are limited to the materials we can add due to traceability, so we were a little reserve.thanks, we will try 309 on some R/D ones and see if it goes away.Thanks,Lamont
Reply:Silver solder is the ticket here. Or if you must weld them pre-heat the hss to 800 deg. F.Pre-heat the s..s. to 400 deg F. Cool slowly and use 316/347 filler.Last edited by welderman1; 12-28-2007 at 06:15 PM.
Reply:I saw at my grandpa's workshop he had made some extended drill bits by brazing another piece of hardend steel onto the bit. Thoose were for some work on my uncles deck (so drilling though wood)What are you useing your bits for? Try useing 309(L) for filler, if not try beveling then try brazing them with silver/nickelI hope that helped. good luck!