Today's offerings are these multi size spotting drill arbors I made of 1018 steel 3/4 cold rolled round stock, useful for milling machines. These allow you to have use of a spotting drill without having to swap in a drill chuck on your milling machine all the time. (depending on collet size)
These feature Harbor Freight hole saw pilot drill bits which have a 135 degree tip and are short and rigid. They work great as spotting drills and at $4.99 for two, you won't find any cheaper!
Your options with what is shown; the drill bit itself fits in a drill chuck or a 1/4" collet. The first arbor shown has 3/4", 7/16" and 3/8" and the other arbor has 3/4", 5/8" and 1/2" steps. (other sizes can be made but these are the common ones I use most)
Now if your milling with any of these size collets and have to stop to drill a spotting hole, odds are one of these will fit the collet you have installed saving you from changing out the collet.
Bits shown are Harbor Freight #68397 & #69069 Bi-metal Hole Saw Pilot Bit Set, 2 Pc. $4.99
These feature Harbor Freight hole saw pilot drill bits which have a 135 degree tip and are short and rigid. They work great as spotting drills and at $4.99 for two, you won't find any cheaper!
Your options with what is shown; the drill bit itself fits in a drill chuck or a 1/4" collet. The first arbor shown has 3/4", 7/16" and 3/8" and the other arbor has 3/4", 5/8" and 1/2" steps. (other sizes can be made but these are the common ones I use most)
Now if your milling with any of these size collets and have to stop to drill a spotting hole, odds are one of these will fit the collet you have installed saving you from changing out the collet.
Bits shown are Harbor Freight #68397 & #69069 Bi-metal Hole Saw Pilot Bit Set, 2 Pc. $4.99
I'm heavily into the next project... 