Former Member | 23/07/2021 15:11:08 |
1085 forum posts | [This posting has been removed] |
old mart | 23/07/2021 15:15:30 |
4655 forum posts 304 photos | Any size you like, it is only for making a spot. |
Swarf, Mostly! | 23/07/2021 15:22:52 |
753 forum posts 80 photos | Hi there, Bill, Just my two penneth - I'd say the 'spot' needs to be big enough to at least fully contain the chisel point on the first proper drill you intend to use. Best5 regards, Swarf, Mostly! |
Steviegtr | 23/07/2021 15:26:44 |
![]() 2668 forum posts 352 photos | I only have 6mm spotting drills but they work for most sizes. I guess a really small hole spotting may be difficult. The spotting drills i have are just from Starret holesaws. They have a very fine point so are ideal & much cheaper. Steve. |
JasonB | 23/07/2021 15:55:30 |
![]() 25215 forum posts 3105 photos 1 articles | Really depends on how you want to treat the hole. A spoting drill can also be used to camfer the edge of the hole prior to it being drilled thus saving one operation in which case an 8mm min or preferably a 10mm 90deg spoting drill would be the best option so you don't have to deburr the entry side.. Larger still if you wanted a fully countersunk hole as the spotting drill can also pre countersink rather than going back after drilling with a CSK bit. I would not really class the holesaw pilot drills as spotting drills, maybe 4-facet or split point but a bit long for spotting so may wander a bit. I mostly use an 1/8" one which does for starting holes upto about 5mm, 5mm one above that or 6mm carbide one in the CNC. |
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