Reaming holes

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I have 40 - 3/4" holes to ream out to 1" , they are in 1" plate on a pull scraper. I was going to drill them with a Mag drill , but am nervous about using a annular cutter to recut these holes. Have never tryed this before and thought the only way to accurately drill them , was to put a 3/4 bit ,set the drill then change to 1" drill then repeat.  Any advice would be greatly appreciated.
Reply:I'd go with the Mag drill, but you should have a drill chuck for it so that you can use a 1" twist drill bit. As long as you seat the end of the bit in the hole before energising the magnet, you should achieve good accuracy.
Reply:Maybe try,  A piece of thick steel  with a 1'' hole as a guide or jig clamp that down and run your mag drill throught it. Keep the bit from walking and brakeing.  I hope that makes sence?DayePound to fit, paint to match
Reply:Forget all that.  I do bridge construction.  We always have to ream out bolt holes so we can poke a bolt on 1" to 8" thick bridge iron.  Get yourself a 1" impact gun and a Bridge reamer.  The reamer goes in the impact gun with a socket.  Insert the reamer in the hole, hit the air and hold on.  Takes less than 30 seconds to ream 3/4" to 1".  Btw a Bridge reamer is like a normal reamer but it has a 1 7/16" hex head on it for the impact gun.Lincoln 300 Vantage 2008300 Commander 1999SA250 1999SA200 1968Miller Syncrowave 200XMT350MPA/S-52E/xr-15Xtreme 12vs Millermatic 251 w/30A  Millermatic 251 Dialarc 250 Hypertherm 1250 GEKA & Bantom Ironwokers
Reply:Originally Posted by Xtreme FabricationForget all that.  I do bridge construction.  We always have to ream out bolt holes so we can poke a bolt on 1" to 8" thick bridge iron.  Get yourself a 1" impact gun and a Bridge reamer.  The reamer goes in the impact gun with a socket.  Insert the reamer in the hole, hit the air and hold on.  Takes less than 30 seconds to ream 3/4" to 1".  Btw a Bridge reamer is like a normal reamer but it has a 1 7/16" hex head on it for the impact gun.
Reply:Originally Posted by Xtreme FabricationForget all that.  I do bridge construction.  We always have to ream out bolt holes so we can poke a bolt on 1" to 8" thick bridge iron.  Get yourself a 1" impact gun and a Bridge reamer.  The reamer goes in the impact gun with a socket.  Insert the reamer in the hole, hit the air and hold on.  Takes less than 30 seconds to ream 3/4" to 1".  Btw a Bridge reamer is like a normal reamer but it has a 1 7/16" hex head on it for the impact gun.
Reply:The title made me think you were asking about a machine or finishing reaming operation. Reaming from .750 to 1.00 is too much for these types. I'd think you'd want to be w/in .030" of finish max.Seem like you have it figured out tho.
Reply:Never heard of that Bridge reamer but it like it.  If you do go the mag drill route be careful, the 1" drill might want to bite and run rough.  It also might run a bit ovesize, so if size is a tolerance you need to hold try one first and adjust accordingly.  This bridge reamer sounds sweet, anyone know who would carry these in Canada?    Grant
Reply:http://www.fastenal.com/web/search/p...310rQjwqQzOnh4Here is the link to fastnels website for bridge reamers.  There are quite a few places you can buy bridge reamers and several manufactures.Lincoln 300 Vantage 2008300 Commander 1999SA250 1999SA200 1968Miller Syncrowave 200XMT350MPA/S-52E/xr-15Xtreme 12vs Millermatic 251 w/30A  Millermatic 251 Dialarc 250 Hypertherm 1250 GEKA & Bantom Ironwokers
Reply:You can also look into a core drill (3 or more flutes intended to open holes while maintaining close sizing). Prolly double the price of a bridge reamer but is easy to re-sharpen.Matt
Reply:Originally Posted by Matt_MaguireYou can also look into a core drill (3 or more flutes intended to open holes while maintaining close sizing). Prolly double the price of a bridge reamer but is easy to re-sharpen.Matt
Reply:Originally Posted by dunemetalI'm sure they are.  The bridge reamers I've seen have a pronounced initial taper and are used to gain a better alignment of boltholes between separate pieces of structural steel. In my mind, shaving .062 off each side of a hole seems a lot to ask of a reamer. Maybe my mind is stuck on reaming to final size a hole bored slightly undersized.