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Concrete drilling problems

I am in desperate need of advice regarding drilling a concrete floor.

My all singing all, dancing American made tube  bender eventually arrived after being held at Customs for nearly a month, and I now need to get it fixed to the floor. The fixings that I am using are 10 mm diameter floor bolts that require a 16 mm diameter hole X 90 mm deep drilling in the floor .... .... .... I am using a standard 1/2 chuck percussion drill, and all I am doing is burning out the drill bits. ...  and so far I've not achieved to drill one full hole for a bolt.

I have considered hiring a "wet" diamond core drilling machine, but none of the local hire companies seem to have 16 mm diamond core bits available.

If needs be I can increase the size of the bolts up to either 12 mm or 16 mm dia bolts, and I know that a 12 mm bolt requires a 20 mm drill bit, but I am unsure about the 16 mm dia bolts.

Any advice about installing floor bolts will be greatly received, as I must have this tube bender bolted down and ready for use as soon as possible due to the appalling delay caused by the Customs and Revenue service eating into my production and delivery schedules.

Get an SDS chucked drill. It will eat up the concrete that your percussion is failing on.

The difference is amazing even when using a cheapo £35 jobby. Get a good drill bit (might even cost more than the drill lol)

I did some fencing down the center of a drive. There were two of us. Me with the sds & a mate with a standard drill. I was doing 4 holes to his one & he was putting all his weight on his & I was doing it one handed. I have even drilled holes with it in reverse without even noticing.

Or use a resin fix  to fix thinner studding in to the floor.
(poss even resin bond a bracket to the floor)

Or get a bolt gun & fire the fixings in.

Thanks for the advice JM

It is a JD2 Model 3 tube bender that I have bought: and I have made a 100 X 100 steel box section post welded to a 750 X 500 X 10 steel chequer plate for it to sit on. I intended to use 10, 10mm dia Rawl bolts to fix it to the floor ..... after all until I can afford and justify a hydraulic power conversion kit I shall be swinging upon 0.9 mtr long handle to form bends in 16 -25 mm tubing and a 1.8 mtr long handle for 40 and 50 mm chrome alloy steel tubing.

It looks like an SDS drill and through bolts will be on the cards first thing Tuesday morning, However, thinking about it the drill produced dust that did come out of the 6mm pilot holes that I managed to get into the floor showing a dark grey colouring rather than the sandy grey concrete colour I was expecting. So tomorrow morning I shall pass a magnet over this dust just to check if I have hit any shallowly placed re-bars.

Could be steel as you say or some odd stone used in the mix.


I rented an SDS drill, and 110v transformer, purchased a 16 mm bit as a consumable item and got my required 10 holes in the floor and the tube bender frame bolted down in less 30 minutes.

It was surprising just how quick and easy the whole process was.

Thank you for the advice.

Your welcome.

Like I said I could not believe that the method of hitting / hammering could make that much difference, but it does.

I got the big tube bender bolted down to the floor on Tuesday morning: hired a big SDS drill and bought a 16 mm bit as a consumible item and got the job done in less than 30 minutes.

Now Cargo Cycles can get on and make some Bike frames and Husky racing rigs.


A very tidy workshop you have Gareth

horace wrote:
A very tidy workshop you have Gareth


Fortunately you can't see the state the rest of workshop is in.

I am away in York with Lois for a long weekend, returning late on Monday night. on the return journey we are coming back via Leicester where I'll be collecting a new tube rolling machine   so that I can bend tubing into larger radii, even into circles. Tuesday morning a delivery of 50 lengths of 5/8, 3/4, 1, and 1 & 1/4  o/d tubing will arrive, and then after lunch, Cargo Cycles begins the manufacturing of cargo bicycle frames and Husky dog racing rigs.  I'll take a couple of photos of a clean and ready to go workshop.

I have just received the Lidl news letter, and from the 13th of May they are offering a 1050 watt SDS drill, with 3 drill bits, chisel, and point for only £34.99 ...... I will buy one; it has a 3 year warranty, but if it only lasts a year, for me it will have paid for it's self.

Yeh thats just the job.

Prob not much more than the hire cost.

Dont they have a 3 year warranty any way?


I have bought the cheap £34.99 Lidl SDS drill this morning, and have already drilled a further 4 off 16 mm diameter holes X 100 mm deep in the floor to fix my steel bar (flat, square, and round bar, but not tubing), manually operated cold forming bender down.

I can highly recommend this cheap Lidl SDS drill.

If it has the option make sure you put fresh grease in it often.

My last one failed cos I dint.

What does SDS stand for please??

Wiki says:

Developed by Bosch in 1975 for hammer drills, the SDS uses a cylindrical shank on the tool, with indentations to be held by the chuck. A tool is inserted into the chuck by pressing in, and is locked in place until a separate lock release is used. The rotary force is supplied through wedges that fit into two or three open grooves. The hammer action actually moves the bit up and down within the chuck since the bit is free to move a short distance. Two sprung balls fit into closed grooves, allowing movement whilst retaining the bit. SDS relies on a tool having the same shank diameter as the chuck; there are three standard sizes:

SDS-Plus: a 10 mm shank with two open grooves held by the driving wedges and two closed grooves held by locking balls. This is the most common size and takes a hammer up to 4 kg. The wedges grip an area of 75 mm≤ (0.116 sq in) and the shank is inserted 40 mm into the chuck.

SDS-top: a 14 mm shank similar to SDS-plus, designed for hammers from 2 to 5 kg. The grip area is increased to 212 mm≤ (0.329 sq in) and the shank is inserted 70 mm. This size is uncommon.

SDS-max: an 18 mm shank with three open grooves and locking segments rather than balls. It is designed for hammers over 5 kg. The wedges grip an area of 389 mm≤ (0.603 sq in) and the shank is inserted 90 mm.

Many SDS drills have a "rotation off" setting, which allows the drill to be used for chiselling. The name SDS comes from the German steck, dreh, sitzt (insert, twist, fits). German-speaking countries may use Spannen durch System (Clamping System), though Bosch uses Special Direct System for international purposes.

Thank you for that I just meant "SDS" we have a "rotary impact drill" that works in similar way and can just chisel, called a "kango hammer"

Generally, a 'hammer drill' is for brick walls etc, a 'rotary hammer' is the big chunky one for concrete and so on, goes in and out more and not so fast round and round.

I've never heard of 'SDS top' before, only plus and max. So I think for practical purposes that's all you'll find, in the UK anyway.

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