joist bolt length

[jon ccc]

hello
i am planning on fixing face joist hangers to support 2inch by 6inch joists on a stone wall in my cellar.
how long should the m12 bolts be?
thanks

 

[theprinceofdarkness]

Stupid answer :- It depends on the strength of the stones used in the wall. I would have thought that 4" will do in most stone, perhaps 6" in sandstone which can be very soft. Four of them per hanger?
Frank

 

[jon ccc]

Hi Frank thanks.
the simpson tie face fixing joist hanger has 4 holes for m12 bolts.
i decided to use anchor sleeve bolt type, so i dont have to use rawl plug and chemical mortar.
http://www.strongtie.co.uk/products/detail/face-fix-hangers/39


the stone wall is very hard to drill into. i have a black n decker 3000rpm drill.
i use the hammer setting, have bought a special masonery dewalt drill set [that amazon reviews said was good on hard stone].
but the dewalt and my other masonry drill bits, after 3minutes of timed drilling. have only penetrated 2cm of the stone.

is this length of time/ penetration rate normal?
do i need to buy a more powerful drill?

 

[^woody^]

You need an SDS drill. Fast speeds will burn the bit out.

Fixings are generally 2.5 x the width of the timber being fixed.

 

[theprinceofdarkness]

I agree you can get a a cheapo SDS drill from catalogue suppliers. My one worked fantasticaly( many holes over 600mm in lime stone!!), drills 10mm in lime stone at a rate of 6" per minute. I had to mend it because the automatic overload clutch let go. I tightened up the nut gave it to my son and bought its big brother (~£70). Its a brute to handle but it drills at twice the rate.
Frank

 

[^woody^]

Dewalt SDS for £60. Use code DEW20

www.toolstop.co.uk/dewalt-d25133k-sds-hammer-2kg-3-mode-26mm-240v-p71687?