*Very* silly question re SDS drills

[Snergle]

OK, this is going to rank high in the "silly question" stakes but here goes:

Wifey has just bought me an SDS drill for my birthday and said that I can christen it by fitting two extra sockets in the living room.

If I was going to do the chases by hand, I'd use a spirit level to draw two parallel vertical lines, the required width of the chase apart and then use a bolster chisel and lump-hammer to either a) chisel completely up one line then the other, or b) chisel about a foot up one line then the other, alternating all the way to the top - rightly or wrongly, this technique has always worked for me in the past.

Now I've got my nice, shiny, new SDS drill and chisel bits - and the silly part of this posting is: what technique do you use with these rascals? Presumably the chase is still done in the same way except that the drill takes the place of the lump-hammer and bolster?

May seem a very simple question but I don't want to break the bloody thing on its first job - and take all the flack that would result. At least she won't see this question and any flack that this generates :o)

Snergle.

[Steven Campbell]

I done this very job a few weeks back. I used the SDS drill to do the chase but found it was a bit to powerful in places for my old "delicate" plaster so I ended up taking out a bit more than I intended to. If you take your time and are careful I see no reason why you shouldn't use the SDS for this. I must say it was great for removing the recess for the wall boxes to fit in. I had always done them by hammer and chisel which was a hellish job, but the SDS is just like a knife going through butter.

Steven.

[Tony Bryer]

I guess it depends on the plaster, but the way that worked best for me with skimmed sand and cement that was liable to detach itself in big pieces if disturbed was to stitch drill either side of the chase (like perforations between stamps) then use the chisel and chasing bits to remove the chase material, leaving the rest undisturbed. If it's soft plaster on a harder background you can probably just cut the chase.

[Snergle]

Snergle

[Stuart Noble]

IME it's best to score the plaster with a stanley knife and go back as far as the brickwork with hammer and bolster. Pretty easy with minimum dust. The sds comes into its own removing the next inch or whatever of brick, but by then you have a neat cut-out on the surface.

[Brian Sharrock]

a bolster chisel should be substitued by a wide SDS chisel ... but instead of the lump-hammer, use the SDS 'machine' - roto stop mode to delicately mark the outside of the lines ... the slightest pressure onto the chisel will suffice . . remember that the chisel won't be thumped until you apply pressure onto it (makes a microswitch or something). Why use your (inaccurate(?)) thumping when you've got a shiny new tool. [You'be probaably only got a 25mm wide SDS chisel though! Buy a wider one!]

Screwfiix do a cranked 25mm wide chaneling SDS chisel; looks something like a shovel; ideal for producing uniform depth channels with straight sides - I find that scoring the path with the wider chisel produces 'nicer' results.

It's worked for me in the past ... HTH

[Saxman]

Aldi have this from Sunday.

1700W Wall Chaser with Laser.

[Sparks]

Then you want one of these :0)

[Al, Cambridge, UK]

Not actually a microswitch: as you apply pressure, the drill-bit is pushed back in the chuck (which allows considerable fore/aft movement) until it contacts the hammer and the mayhem starts. The SDS bit is actually being hammered directly which is why it works so well. That sounds pretty violent but it's actually reasonably controlled - as Brian says, it almost feels like a switch.

But be careful when drilling all the way through a brick wall (or concrete post, or everything I've tried so far) - I haven't yet been able to avoid blasting out a neat conical exit wound, even when slowing right down for the last 10mm.

Hope that helps, enjoy your toy, Al.

[Snergle]

Hey thanks everyone. I thought I was going to get laughed at for asking such a silly question but got lots of advice there - even links to new toys for my new toy. Brilliant :o)

Snergle.

[T i m]

I found the quickest and most gentle (and not as dusty as folk say) was the twin diamond disk 'wall chaser' (attached to a fresh Henry vacuum). This makes for a perfectly neat two sides and a second run leaves tiny 'walls' of plaster / render / brick / block that break away very easily (so this is probably the quietest solution) ;-)

you are cutting into block work then you can simply scrape the bottom of the slot flat with a suitable width chisel. If hard brick you can use the wall chaser as a sort of router and get it lovely ;-)

For the electrical boxes I use one of the plastic drill templates as that allows you to set the depth accurately and keeps the drill holes all going where they should, leaving a small amount of chisel work to finish the job. (can't find a link atm) ..

I'm not sure I'd use an SDS chisel to do either of the above jobs on this (1897) house .. it would probably knock it to bits! ;-(

All the best ..

T i m

[John Rumm]

What works best will depend on your plaster and also your drill. With modern plaster, the SDS guaging chisels[1] work very well. These cut the complete chase in a single action - all you need do is steer it in the right direction. For older plaster (especially any where the skim coat has a tendency to separate from the base coat) I find the wide chisel[2] bit used to cut two parallel lines works well. Using a slight up or downward angle on the chisel allows the progress along the chase to be made at the same time as through the plaster - hence no ned to keep lifting and repositioning the drill.

This is also one of those cases where a drill with a nice delicate speed control is *much* better than the "all or nothing" of some models.

[1]