Thread cutting bolt question

[stevep1954]

i'm using 3/8" thread cutting bolts to secure my casters on my table thru approx. 1/2" plates and was wondering if a 1/4" hole was the proper size to drill to get these bolts started? also can i use a 1/4" cordless impact driver to do the initial thread cutting or would a 1/2" drive socket be safer? thanks

 

[454ragtop]

Haven't used that style bolt, but I think I'd use the tap drill size, which for 3/8-16 is 5/16".
HTH, Jim

 

[Beemer533]

I think the hole size for a 3/8" bolt is 5/16" (for tapping at least), I would guess that the thread cutting bolt is the same. For a plate that thick, I think 1/4" is too small.

For a 1/2 " thick plate I think I would stick with a hand held driver... I think you meant 3/8 drive though, not 3/4?

 

[kjbenner]

1/4 would be smaller than the minor diameter on a 3/8 thread. 5/16 is the tap size for 3/8-16; you'd probably be better off with that. I don't have experience with these to be sure, but I would think that a 3/4 drive socket would be overkill.

 

[stevep1954]

i meant my 1/2" drive socket set with the correct size socket. with a 1/4" hole the first bolt i turned in was a little tight...

 

[larry_g]

Couple of basic questions here

1. Can you link to the bolt your working with?
2. Are you working in metal, wood or some other material?


lg
no neat sig line

 

[pancho400cid]

It must have been sheet metal or you would never have driven a 3/8" bolt into a 1/4" hole.

There are probably a thousand types of thread cutting bolts, so not 100% sure what you are working with.

For reference, where I work we use "Taptite" self-tapping bolts, with a pre-drill dia of .344", but that is into fairly thick (at least one bolt dia normally) material.

UPDATE - I see you said matl was 1/2" thick.... can't imagine how you got that 3/8" bolt to go into a 1/4" hole without breaking it.

 

[SARG]

For that application I would favor nuts-n-bolts over the self tappers.

 

[stevep1954]

these are the tables i am working on. i have only put in one bolt so far. i will change to a 5/16" bit and see how that works. to drill the holes in the feet for the casters i swung the table out of the way on my drill press and rolled the tables upside down on a cart up to the press and lined up the bit to the punch marks i made and away i went… worked great but too darn cold in the shed this time of year.

 

[404]

There will be a data sheet for the bolts telling the correct size. Are these by Parker Kalon?

 

[stevep1954]

there isn't room for a nut and washer on the top side, too close to the 3" by 3" leg. not sure who made the bolts, got them from fastenal. we have a competent one here in Rochester, MN.