ssray Posted July 21, 2021 Report Share Posted July 21, 2021 I'm finally at the stage of fitting glass balustrade to our garden stairs, having to drill a 12mm hole in steel that is about 25mm I have 2x brand new 12mm hss bits and 3 in one oill Should I pilot it? Or say start at 7mm then move up in stages? Ta Quote Link to comment Share on other sites More sharing options...
426hemi Posted July 21, 2021 Report Share Posted July 21, 2021 6 minutes ago, ssray said: I'm finally at the stage of fitting glass balustrade to our garden stairs, having to drill a 12mm hole in steel that is about 25mm I have 2x brand new 12mm hss bits and 3 in one oill Should I pilot it? Or say start at 7mm then move up in stages? Ta It’s 25mm thick? I’d hire a mag drill. 2 Quote Link to comment Share on other sites More sharing options...
Alex_H Posted July 21, 2021 Report Share Posted July 21, 2021 I'd pilot definitely, 3 6 9 12, plenty of cutting compound. Unless it's stainless, then get someone with a 50cal to shoot it and hope for the best, it'll be a bit over 12.7mm when it's shot but you'll have a hole! 1 3 Quote Link to comment Share on other sites More sharing options...
RonniB Posted July 25, 2021 Report Share Posted July 25, 2021 Go slow, use cutting oil and don’t let the drill overheat. And if it’s stainless use cobalt drills (HSCO) or you’ll get nowhere 1 Quote Link to comment Share on other sites More sharing options...
jollygiant Posted July 25, 2021 Report Share Posted July 25, 2021 Go straight in dry with the 12mm and don't even centre punch it, you know the PB way! 7 Quote Link to comment Share on other sites More sharing options...
peter187 Posted July 26, 2021 Report Share Posted July 26, 2021 Hire a magdrill with a mag base. If you try to do this with a pistol drill the results are going to be awful and pissed by a mile. Quote Link to comment Share on other sites More sharing options...
jaycee Posted July 26, 2021 Report Share Posted July 26, 2021 (edited) On 7/21/2021 at 6:15 PM, 426hemi said: It’s 25mm thick? I’d hire a mag drill. 1 hour ago, peter187 said: Hire a magdrill with a mag base. If you try to do this with a pistol drill the results are going to be awful and pissed by a mile. Definitely this. I didn't even know the things existed until I had a really awkward job for work and my manager told me that he'd hired one for me. Also, cutting paste, proper new drill bits, and definitely work your way up the drill sizes for a hole that diameter. Edited July 26, 2021 by jaycee Quote Link to comment Share on other sites More sharing options...
ssray Posted July 26, 2021 Author Report Share Posted July 26, 2021 Did it, started with a new bosch 12mm,mistake tried to break my wrist So cobalt bits purchased, 3mm 5,6,8,and 12 Still took a while to do But now I need to cut a slot in the metal Web under the stair tread As the nut touches it and I can't get it threaded, too small a gap to remove a bit of the nut on one side Ideas? Quote Link to comment Share on other sites More sharing options...
lorenzo Posted July 26, 2021 Report Share Posted July 26, 2021 42 minutes ago, ssray said: Did it, started with a new bosch 12mm,mistake tried to break my wrist So cobalt bits purchased, 3mm 5,6,8,and 12 Still took a while to do But now I need to cut a slot in the metal Web under the stair tread As the nut touches it and I can't get it threaded, too small a gap to remove a bit of the nut on one side Ideas? What's hanging off it? Maybe pop a rivnut in there? Can you even get M12 rivnuts? Quote Link to comment Share on other sites More sharing options...
jollygiant Posted July 26, 2021 Report Share Posted July 26, 2021 1 hour ago, ssray said: Did it, started with a new bosch 12mm,mistake tried to break my wrist So cobalt bits purchased, 3mm 5,6,8,and 12 Still took a while to do But now I need to cut a slot in the metal Web under the stair tread As the nut touches it and I can't get it threaded, too small a gap to remove a bit of the nut on one side Ideas? I'd try filing one side of the nut down until it fits between the web and the thread, so you end up with an out of shape nut if you know what I mean. Then you won't need a spanner to hold the nut to hold it still. 1 Quote Link to comment Share on other sites More sharing options...
ssray Posted July 26, 2021 Author Report Share Posted July 26, 2021 1 hour ago, jollygiant said: I'd try filing one side of the nut down until it fits between the web and the thread, so you end up with an out of shape nut if you know what I mean. Then you won't need a spanner to hold the nut to hold it still. Not enough meat left, I did that on the other ones, 1 Quote Link to comment Share on other sites More sharing options...
jollygiant Posted July 26, 2021 Report Share Posted July 26, 2021 1 hour ago, ssray said: Not enough meat left, I did that on the other ones, Ok, warm the thread up and whack with a hammer so it'll be riveted! 1 Quote Link to comment Share on other sites More sharing options...
DesmoEddy Posted July 26, 2021 Report Share Posted July 26, 2021 (edited) 7 hours ago, ssray said: Did it, started with a new bosch 12mm,mistake tried to break my wrist So cobalt bits purchased, 3mm 5,6,8,and 12 Still took a while to do But now I need to cut a slot in the metal Web under the stair tread As the nut touches it and I can't get it threaded, too small a gap to remove a bit of the nut on one side Ideas? You have a round 12mm hole, through 25mm steel, and you need to turn it into a slotted hole? Edited July 26, 2021 by DesmoEddy Quote Link to comment Share on other sites More sharing options...
ssray Posted July 26, 2021 Author Report Share Posted July 26, 2021 5 hours ago, DesmoEddy said: You have a round 12mm hole, through 25mm steel, and you need to turn it into a slotted hole? Not quite, the 12mm hole is for the bolt 5o go through, the stairs have a web/stiffener in the middle This is where I need to cut a slot so the nut will got on the bolt thread Quote Link to comment Share on other sites More sharing options...
agressor Posted July 26, 2021 Report Share Posted July 26, 2021 1 hour ago, ssray said: Not quite, the 12mm hole is for the bolt 5o go through, the stairs have a web/stiffener in the middle This is where I need to cut a slot so the nut will got on the bolt thread Jesus, You are adult aren't You... just screw up the job, deal with it and take a beer. Thats what adult mens do. 3 Quote Link to comment Share on other sites More sharing options...
jaycee Posted July 26, 2021 Report Share Posted July 26, 2021 49 minutes ago, agressor said: Jesus, You are adult aren't You... just screw up the job, deal with it and take a beer. Thats what adult mens do. Make sure to blame the wife and kids for not giving you peace to do a proper job. When she complains, throw down your tools and storm off yelling, "Well you bloody do it then!" 😁 3 Quote Link to comment Share on other sites More sharing options...
Ray Von Posted July 27, 2021 Report Share Posted July 27, 2021 Cut head off bolt and stick down with no nails. Not my job mate! 1 Quote Link to comment Share on other sites More sharing options...
Mohawk Posted July 27, 2021 Report Share Posted July 27, 2021 If doing that kind of drilling free hand, always start with a pilot that is same size as final drill tip flat for 12mm final its around 1.5-2mm pilot. Drill pilot accurately & the final size drill will stay centred in the pilot hole. But for that depth as previously advised you need a static drill tool. 1 Quote Link to comment Share on other sites More sharing options...
GSXR814 Posted July 27, 2021 Report Share Posted July 27, 2021 On 7/26/2021 at 7:27 AM, ssray said: Did it, started with a new bosch 12mm,mistake tried to break my wrist So cobalt bits purchased, 3mm 5,6,8,and 12 Still took a while to do But now I need to cut a slot in the metal Web under the stair tread As the nut touches it and I can't get it threaded, too small a gap to remove a bit of the nut on one side Ideas? Angle grinder with a 1mm slitting/cutting disc fitted. Cut into the material and generate enough clearance. Wear safety glasses as steel splinters in the eyeball are neither big nor clever!! 2 Quote Link to comment Share on other sites More sharing options...
ssray Posted July 28, 2021 Author Report Share Posted July 28, 2021 8 hours ago, grinder said: Angle grinder with a 1mm slitting/cutting disc fitted. Cut into the material and generate enough clearance. Wear safety glasses as steel splinters in the eyeball are neither big nor clever!! Thanks, it's done, no broken wrist, must be all the exercise it's had, Going to angle gring at the weekend, gawd knows how I'm going to have to lie down to do it Quote Link to comment Share on other sites More sharing options...
GSXR814 Posted July 28, 2021 Report Share Posted July 28, 2021 Pic would help 1 Quote Link to comment Share on other sites More sharing options...
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