When a 1/4" bit is not 1/4"

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mark32

mark32

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Currently in NJ
I went to buy some masonary bits for my new TE-6 (1/4" and 3/16") and noticed the 1/4" seemed a litle large. I then pulled a 1/4" bit from a box of plastic anchors and sure enough the Hilti was larger. This bothers me because I also use 1/4" tapcons and I know if the hole is too big they won't hold, I didn't get the chance to compare the 3/16" bits though. Has anyone noticed this?
 
I too found I needed to undersize the tapcon bit. Used a bosch 3/16 for tapcons that needed a 3/16 and the screws wouldnt hold -had to go to the 5/32
 
BryanMD said:
I always use a smaller masonry bit with tapcons than what they recommend and suggest that you do the same. I also suggest you buy and use BOSCH masonry bits exclusively.

Where Tapcon says to use a 3/16" bit... I use a 5/32" (etc).
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I wonder if that is becase the hole is getting to big because of wobble when drilliing? It's easy to make to big a hole in mansonry.
 
I use Bosch bits, and have never had a problem when using the bit size specified on the package. I do not care for the included bits.

c2500
 
I use the size specified, but I can't use the bit they come with in my Hilti which uses SDS+. If I'm careful to make a clean hole (no wobble) it usually works pretty well. If it's really soft brick, I may need to use a longer screw or stick some toothpicks in the hole - that is a trick that has saved me many times.:grin:
 
Okay, if I were keeping score two members undersize their masonary bits and three members use the specified sizes. Remember though, I'm comparing Hitli's SDS plus bits to the bits that come with anchor sets.
 
Sharpie said:
I use the size specified, but I can't use the bit they come with in my Hilti which uses SDS+. If I'm careful to make a clean hole (no wobble) it usually works pretty well. If it's really soft brick, I may need to use a longer screw or stick some toothpicks in the hole - that is a trick that has saved me many times.:grin:
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toothpicks degrade over time. try using plastic or lead if you want the anchor to hold over time.
 
mark32 said:
Okay, if I were keeping score two members undersize their masonary bits and three members use the specified sizes. Remember though, I'm comparing Hitli's SDS plus bits to the bits that come with anchor sets.
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You need to use the propere sized bits. 1/4" tapcon screws do not use a 1/4" bit. 5/16" screws do not use a 5/16" bit. If you look at a tapcon screw, you wilil see two different sized threads. The bit used to drill the hole must fit the smaller diamiter thread. If you buy a box of screws it will come with the proper sized bit.
 
Sharpie said:
I use the size specified, but I can't use the bit they come with in my Hilti which uses SDS+. If I'm careful to make a clean hole (no wobble) it usually works pretty well. If it's really soft brick, I may need to use a longer screw or stick some toothpicks in the hole - that is a trick that has saved me many times.:grin:
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Toothpicks probably violate 110.13 (A)
 
nakulak said:
toothpicks degrade over time. try using plastic or lead if you want the anchor to hold over time.
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Or strands of copper wire. I've cut a chunk of straned wire, put it into the hole, and screwed the screw right into the center of the wire bundle.
 
IMO the best bit size depends on the hardness of the material drilled. Such as the bit needs to be slightly smaller for softer crumbly materials such as old brick.
 
Cavie said:
You need to use the propere sized bits. 1/4" tapcon screws do not use a 1/4" bit. 5/16" screws do not use a 5/16" bit. If you look at a tapcon screw, you wilil see two different sized threads. The bit used to drill the hole must fit the smaller diamiter thread. If you buy a box of screws it will come with the proper sized bit.
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Hi there Cavie, I initially stated I wanted a 1/4" bit to use with plastic anchors, and a 3/16" bit for the 1/4" Tapcons, thanks though.
 
Thanks, good suggestions on other materials to use instead of wood. I don't know how I missed 110.13(A) :mad:
 
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