================================ I've got a couple of 5 x 210mm and 5.5 x 210mm 'ARMEG' bits. I can't remember where I bought them but Axminster stock Armeg so they might get them for you although they don't show in their catalogue.
I also found this place (never tried them) to confirm that the sizes are available:
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found that a 5.5mm hole made for easier fixing in hard bricks.
I had exactly the same problem as the OP, no long series 5mm sds for
6x140mm multimonti, and found like you that 5.5mm is sometimes preferable in hard materials.
I occasionally have the same problem with 10mm multimonti that are reluctant to go into 8mm holes in hard concrete - unfortunately no 8.5 or 9mm sds available.
I've found that the clout of a cordless impact driver with a socket on the front can frequently "help" a multimonti into that "bit too tight" hole.
I guess it might also be possible to grind a tiny bit of the flutes of the tip of a 5.5mm sds bit (as the spiral must be slightly narrower anyway) so as not to drill an overly loose hole.
================================ The 210mm bit has a stated useful drilling length of 150mm but would go to
155mm if pushed hard. If you're desperate for extra depth you could drill a shallow countersink in the timber wide enough to accommodate the nose of the chuck.
On Sun, 6 May 2007 22:29:54 +0100, "The Medway Handyman" mused:
I'd give up at this point and use bigger multi montis and get the longer, bigger bits out, or just mark the holes then drill the depth without the post in the way. Being lazy though, I'd use bigger fixings so I didn't have to remove the post.
The objective is to avoid removing the post as you say. Bigger fixings is a good idea, but bigger cost a lot more. 6 x 140 are £14 per 50, Plus 6mm is the biggerst countersunk fixing - pan or hex head would cause a problem.
=============================== This page shows how the lengths are generally measured:
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Axminster don't stock 5mm x 210mm
This page shows ARMEG bits:
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to Products / Hammer drilling / QFDS and then scroll down to see 'working lengths' in a table of sizes.
This page shows a stockist:
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think that 'multi montis' are a bit over-rated especially for the kind of job you're currently doing. I use coach screws with plastic plugs and penny washers. My method which involves no post removal is to fix the post loosely at the top with one coach screw / plug / penny washer. I then drill small holes (1/4") through the wood with a wood drill at suitable positions. Then plumb the post and drill through the 1/4" holes with a masonry drill just enough to provide a mark on the brickwork. Next swing the post out of the way using the previously fixed top fixing to hold it. Now drill holes for all the plugs using the marks made through the 1/4" holes and insert the plugs. Next carefully drill out the 1/4" holes in the wood to the size of your coach screws (a little oversize is best). Swing the post into position and fix with coach screws and penny washers which can be counter-sunk if necessary.
That's exactly what I've been doing - and why I went for the multi montis - to speed things up. They seem to give a very strong fixing.
My plan was to pre drill the post, drill & fix one hole to wall, plumb the post & fix the rest of it. It will work if I can find a long enough 5mm SDS bit.
=============================== Well since you're happy with 'multi montis' I've just measured an 'Armeg'
5.5mm x 210 mm and I can confirm that the working length is a good 150mm and 155mm if you pushed it hard so it should easily do your job. I would expect bits of the same overall length from another manufacturer to be roughly the same working length so the link I gave you to a stockist (Leo) seems your best source.
I'm guessing, that for MH the major element of his customer bill, is probably for his time. That ability to fully predrill the timber (possibly off-site), then just drill through for fixings - may be important in controlling costs.
That to me is the main advantage of multimontis over other fixings - speed (and to a lesser extent removability). I've been doing quite a few joist hangers recently, 50 or so in the last month (the bolt-on, retrofit type), so 200 multimontis - so really appreciate the speed and convenience.
If other people are working the same way - I'm sure the availability of long/thin/odd-size sds bits will catch up.
I think this is the same effect as we're seeing with timber fixings - lots of people say they don't really use nails any more - as an impact driver will put a screw in faster and produce a more secure fixing (ok for the ultimate speed, and where they can be used, gas nailers) - but bash them with a hammer nails don't get used much.
True. I use joist hangers on decking sometimes & fix them with 6 x 50 turbo gold coach screws. Hex head & magnetic driver means they go in tight spaces one handed & a 14:4v driver wacks them in in seconds. Can't wait to try an impact driver on them!
=============================== I certainly agree with what you say and it's not just about cost either. The sheer convenience and labour saving of fixings like these ('multi montis') and such things as power drivers to install them have changed the way people think of doing many jobs.
However, I think it's also important not to abandon more traditional methods if they do a better job. I always have standard screwdrivers to hand in case I have a job needing the 'personal touch'. Likewise, handsaws, chisels etc, still have their place even when power tools are readily available.
Oddly on topic, I managed to find the first thing that an impact driver would not hack the other day...
I was fixing some 4"x2" gate frame posts to the side of an opening in a fence formed by two concrete posts. SDSed the holes in the post, taped in a brown plastic plug and set about driving a 4"x12 twinthread screw through said post (predrilled) and into the plug with the impact driver. As expected the screw romped home and were happy to countersink themselves right through the post had one have wanted.
Having got the wood posts fitted, I realised that the concrete posts were actually leaning toward each other such that the gate would need to be over an inch narrower at the top! Rather than bodge the gate I decided to take the posts off, and cut firrings to go behind them to remove the lean of the concrete posts. I was somewhat surprised to find that my monster 150 Nm 18V Makita impact driver was unable to get some of the screws right out of the post, they started coming out, but no matter how much I tried they would not undo totally. Strangely I was able to loosen them by hand with a manual screw driver. Also I found my
50(ish)Nm 18V combi drill would shift them without any difficulty as well.
I worked that what was happening was the end of the screw was well fixed in the plug, but getting on for 2 1/2" inches of screw was outside the plug. There was enough torsional elasticity in the 12 gauge screw to completely absorb the rotational impact from the driver without the end of the screw needing to turn. So it was not lack of torque that was the problem, but lack of sustained torque to "wind up" the screw enough to shift the end of it.
=============================== I think it's also worth considering an undersize hole (e.g.4.5mm instead of 5mm)in softer materials using a standard hammer drill rather than SDS. I think these fixings are a bit of a mixed blessing and have to be used with due regard to what they're going into and what they're going to hold.
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