I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap will then
be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv straps are
in place and fixed, so I can't allow the holes I drill to wander off line.

I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until a cm or
so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I recall
someone posting here that SDS bits should not be used with a pilot hole, due
to way they work.

#2 bolt straps to vertical studs first and drill through the clearenance
holes - risk here is damage to clearance finish, and this is external job so
need the protection.

"Rick Hughes" wrote in message
...

#2 bolt straps to vertical studs first and drill through the clearenance
holes - risk here is damage to clearance finish, and this is external job
so need the protection.




#2 should have read ... "risk of damage to galv finish "

In article ,
Rick Hughes wrote:
The main thing is here is that the holes in the 10mm thick galv straps
are in place and fixed, so I can't allow the holes I drill to wander
off line.

I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until a
cm or so into the material.

Any drilling into concrete hand held will wander a bit due to the
differences in the ballast.

--
*El nino made me do it

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 3 Jan 2009 12:38:17 -0000, Rick Hughes wrote:

#1 use a non SDS pilot hole, before using SDS drill ... although I
recall someone posting here that SDS bits should not be used with a
pilot hole, due to way they work.

IMHO a pilot hole is the way to go. For a 16mm SDS that needs to be 6mm or
so to properly center the SDS bit. The pilot doesn't need to be full depth
just a cm or so to get the main bit started.

Remember with SDS let the drill/action do the work no need to push hard
like you do with a normal "hammer" drill, just push enough to stop the bit
rattling in the bottom of the hole.

--
Cheers
Dave.

Rick Hughes wrote:
I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap
will then be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv
straps are in place and fixed, so I can't allow the holes I drill to
wander off line.
I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until
a cm or so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I
recall someone posting here that SDS bits should not be used with a
pilot hole, due to way they work.

#2 bolt straps to vertical studs first and drill through the
clearenance holes - risk here is damage to clearance finish, and this
is external job so need the protection.

Use #2. But don't fully tighten the bolts into the studs. Then if the
holes wander you can move the strap slightly or if necessary reposition the
strap . Drill a pilot with say a 8mm SDS bit through the hole, then remove
the bottom fixing in the strap so you can swing it to away & carry on with a
16mm bit.

Never heard that SDS can't be used with pilot holes.



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Rick Hughes wrote:
I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap will
then be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv straps
are in place and fixed, so I can't allow the holes I drill to wander off
line.

I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until a
cm or so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I
recall someone posting here that SDS bits should not be used with a
pilot hole, due to way they work.

#2 bolt straps to vertical studs first and drill through the
clearenance holes - risk here is damage to clearance finish, and this is
external job so need the protection.



Possibly best to get the hole started with rotary drilling only until
you are 20mm or so down.

Maybe make a sacrificial jig drilled off your galvanised parts. Drill
the first hole into the concrete and bolt or otherwise fix that end of
the jig, then drill the furthermost hole and fix the jig again. Then
drill the remaining holes.
HTH
Bob

Rick Hughes wrote:

I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap will then
be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv straps are
in place and fixed, so I can't allow the holes I drill to wander off line.

I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until a cm or
so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I recall
someone posting here that SDS bits should not be used with a pilot hole, due
to way they work.

#2 bolt straps to vertical studs first and drill through the clearenance
holes - risk here is damage to clearance finish, and this is external job so
need the protection.


SDS wanders much less than ye olde hammer drill or vanilla rotary
drilling. SDS will always be prone to wander in concrete, but wander
is as good as zero in a sand/cement only mix IME. So
- sticking to sds is your best bet
- sds will be prone to wander in concrete, full stop
- pilot holes will reduce the odds of wander to some extent, but wont
eliminate it

Masking tape can mark the spot, and add 2 long bold lines so no mater
where you end up drilling you can see exactly where its meant to be.
Now, if any end up off position you can drill them out larger, which
isnt a problem with resin fixing.

If for some reason you needed 100% perfect position every time, you
could drill out larger and fill with sand/cement mix, which once cured
a few days will then drill accurately every time. But it doesnt sound
like there's any need for that, resin will take up any slack.


NT

"Rick Hughes" wrote in message
...
I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap will
then be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa

Why are you installing an angle piece, when drilling directly into a timber
base plate is neater? The vertical wooden studs run off the wooden base
plate.

Maybe make a sacrificial jig...

That's exactly what I did to set 40 or so surface mount joist hangers.
Made up my jig from drawing around the shape and holes of a joist
hanger on an offcut of joist, through holes in jig done on a pillar
drill, marked out a batten with the required positions of the joist
hangers, screwed batten to laser line on wall, screwed jig to batten
in 1st position, sds-drilled holes into wall, moved jig to next
position etc. Result - joist hangers set prefectly level to a laser
line.

However that does sound a bit overkill for setting strapping. If the
OP's diagram is correct, there's plenty of lattitude for "hammer
adjustment" to get the strap drilling lined-up over the holes. Why the
custom metalwork - why not just use some lateral restraint straps (the
type usually used for floor/wall connection)?

If you need something meaty, e.g. :
http://www.screwfix.com/prods/74769/...0mm-Pack-of-10

Rick Hughes wrote:
I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap
will then be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv
straps are in place and fixed, so I can't allow the holes I drill to
wander off line.
I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until
a cm or so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I
recall someone posting here that SDS bits should not be used with a
pilot hole, due to way they work.

#2 bolt straps to vertical studs first and drill through the
clearenance holes - risk here is damage to clearance finish, and this
is external job so need the protection.

Why are you trying to fix L brackets to concrete and then affix timber to
these? - there is very little, if any strength in doing it that way - far
better to build the studding framework and bolt this directly down to the
concrete using frame fixing bolts, no resin, no plugs, they just tighten up
into masonry and don't budge....you'll need a 10mm bit and the holes can br
drilled directly through the timber and into the concrete....you can lay a
length of DPC down prior to affixing the studding if you are worried about
timber rotting.

--
Phil L
RSRL Tipster Of The Year 2008

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Rick Hughes"
saying something like:

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I recall
someone posting here that SDS bits should not be used with a pilot hole, due
to way they work.

******** to the knowalls.
Just drill the first 10mm with the hammer off.

In article ,
Grimly Curmudgeon wrote:
******** to the knowalls.
Just drill the first 10mm with the hammer off.

Have you ever drilled decent concrete?

--
*Prepositions are not words to end sentences with *

Dave Plowman London SW
To e-mail, change noise into sound.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

In article ,
Grimly Curmudgeon wrote:
******** to the knowalls.
Just drill the first 10mm with the hammer off.

Have you ever drilled decent concrete?

Thousands of times, yes.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

In article ,
Grimly Curmudgeon wrote:
******** to the knowalls.
Just drill the first 10mm with the hammer off.

Have you ever drilled decent concrete?

****. Don't know why I wrote 10mm - 2mm was what I meant.

"Doctor Drivel" wrote in message
...

Why are you installing an angle piece, when drilling directly into a
timber base plate is neater? The vertical wooden studs run off the wooden
base plate.



Studs fix to bottom of panel (150 x 50) that rests on a 150 x 50 wall plate
that is frame fixed at 450mm intervals to 3 course high dwarf brick walls
.... because of wind 'up loading' ..... the biggest risk is wind lifting
whole structure off the slab ---- either with the dwarf wall or ripping it
off dwarf wall.


The restraint straps fix first into slab and then 2 fixing points into
wood - one into the wall plate and one into vertical stud.
Take a look at http://tinyurl.com/7fljlt
This was original sketches with Structural Engineer ... gauge had to be
increased to 10mm to meet pull out forces.

"Phil L" wrote in message
m...

Why are you trying to fix L brackets to concrete and then affix timber to
these? - there is very little, if any strength in doing it that way - far
better to build the studding framework and bolt this directly down to the
concrete using frame fixing bolts, no resin, no plugs, they just tighten
up into masonry and don't budge....you'll need a 10mm bit and the holes
can br drilled directly through the timber and into the concrete....you
can lay a length of DPC down prior to affixing the studding if you are
worried about timber rotting.

--
Phil L

Phil see previous answer .... explains why it has been done this way ...
also wanted all wood to be at least 150mm up off concrete salb.

I habe 150 x 150 gallow posts for main supports and they are also via resin
fixed galv plates, rather than wood to concrete.

"Rick Hughes" wrote in message
news

"Rick Hughes" wrote in message
...

#2 bolt straps to vertical studs first and drill through the clearenance
holes - risk here is damage to clearance finish, and this is external job
so need the protection.



Remember now that the reason given was that for a 'normal' masonry drill,
tip meets as an equal angle arrow head.
for SDS the angles do not meet, they are off set, and to work correctly the
comment was that edge needs to be gripping on concrete .... and putting in a
pilot hold first messes this up ? .....
maybe it was correct, maybe not.

Rick Hughes wrote:

I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right
angle straps are being bolted to slab ... the vertical portion of
strap will then be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv
straps are in place and fixed, so I can't allow the holes I drill to
wander off line.

I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until
a cm or so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I
recall someone posting here that SDS bits should not be used with a
pilot hole, due to way they work.

#2 bolt straps to vertical studs first and drill through the
clearenance holes - risk here is damage to clearance finish, and this
is external job so need the protection.

If you hit a re-bar your fu*ked

"Rick Hughes" wrote in message
...
I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.

The holes will be used to resin in anchor studs, and then right angle
straps are being bolted to slab ... the vertical portion of strap will
then be secured to vertical studs of timber frame walls.
http://tinyurl.com/87wnxa


The main thing is here is that the holes in the 10mm thick galv straps are
in place and fixed, so I can't allow the holes I drill to wander off line.

I have an SDS drill and a new 16mm bit.

When I have drilled SDS holes before they tend to wander about until a cm
or so into the material.

Any tips on doing this ....
some options I have thought of are :

#1 use a non SDS pilot hole, before using SDS drill ... although I
recall someone posting here that SDS bits should not be used with a pilot
hole, due to way they work.

#2 bolt straps to vertical studs first and drill through the clearenance
holes - risk here is damage to clearance finish, and this is external job
so need the protection.

Don't use an SDS if you need it accurate.

Use a diamond core drill

In article ,
Grimly Curmudgeon wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

In article ,
Grimly Curmudgeon wrote:
******** to the knowalls.
Just drill the first 10mm with the hammer off.

Have you ever drilled decent concrete?

****. Don't know why I wrote 10mm - 2mm was what I meant.

A 2mm SDS drill?

--
*Can atheists get insurance for acts of God? *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
Grimly Curmudgeon wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Plowman (News)"
saying something like:

In article ,
Grimly Curmudgeon wrote:
******** to the knowalls.
Just drill the first 10mm with the hammer off.

Have you ever drilled decent concrete?

****. Don't know why I wrote 10mm - 2mm was what I meant.

A 2mm SDS drill?

I think he meant depth rather than width

--
Phil L
RSRL Tipster Of The Year 2008

"RW" wrote in message
...



Don't use an SDS if you need it accurate.

Use a diamond core drill

I already have the 16mm SDS bit .... so have to use that, can't afford to
go buy another bit (not even sure you can get a 16mm core drill that will
drill 150mm deep.

"zaax" wrote in message
...


If you hit a re-bar your fu*ked

Didn't hit rebar (they were deeper, but did hit the reinforcing mesh a few
times .... drilled the holes yesterday ... and hit rebar on 4 of them.
Once I hit the bar, I swapped to my normal rotary drill with a 16mm HSS bit,
and about a minute of that on medium speed would but enough of a 'dimple' in
the bar to allow SDS drill to chip it's way through and as long as you go
slow, the bit does not catch.

All holes completed ... but as weather is very cold at moment will not resin
studs in yet.


I followed advice here .... used a 6mm drill to create a start point (couple
of mm deep only) then started 16mm SDS on rotation only until it had gone
in a few mm, and then switched to impact ... all holes exactly where I want
them.