Author Topic: Long SDS Quick drill bit  (Read 715 times)

Offline Rob

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Long SDS Quick drill bit
« on: December 14, 2018, 02:50:56 pm »
I use a Bosch Uneo a lot, which uses SDS Quick bits. The main problem is i'd like an 8mm bit that is longer than the standard 8x75x120, ideally ~250m so i can Hilti cap. Does anybody know if these are available anywhere?

Alternatively, an SDS Quick - SDS adapter would be awesome (even better actually), but i can't find one of them online either.

Any ideas anyone?
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Offline Huge

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Re: Long SDS Quick drill bit
« Reply #1 on: December 14, 2018, 04:35:19 pm »
I asked on here, a while back, about longer SDS quick drill bits but no one was able to help. Since then, despite looking, I still haven't found any. I suspect, due to the low power of the Uneo, that they aren't manufactured?

Offline Rob

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Re: Long SDS Quick drill bit
« Reply #2 on: December 15, 2018, 08:27:27 pm »
I suspect you're right, although in my experience they'd handle a 250mm 8mm hole fine, and spare batteries are so light to carry.

I've seen inklings online of SDS Quick -> SDS adaptors, but can't find one available anymore. Is anyone metal savy able to machine one up? I imagine there might be a (small) market for them....
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Offline Huge

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Re: Long SDS Quick drill bit
« Reply #3 on: December 16, 2018, 08:37:33 am »
Or would it be possible to weld two bits together?

Offline T pot 2

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Re: Long SDS Quick drill bit
« Reply #4 on: December 16, 2018, 08:43:57 am »
Try the discount shopping centre at the back of Jo royals on buxton market place it is situated in the old otter control buildings. You can buy them up to 1 metre
long.

Offline Huge

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Re: Long SDS Quick drill bit
« Reply #5 on: December 16, 2018, 08:46:57 am »
in my experience they'd handle a 250mm 8mm hole fine

How did you discover that if there are no long drill bits? Is it from drilling several short holes, one after the other? The extra friction from a long drill bit in a long hole, may make a big difference?

Offline Rob

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Re: Long SDS Quick drill bit
« Reply #6 on: December 16, 2018, 09:07:19 pm »
How did you discover that if there are no long drill bits? Is it from drilling several short holes, one after the other? The extra friction from a long drill bit in a long hole, may make a big difference?
I doubt there's much friction moving powder up a hole, verses smashing the sh*t out of limestone. I'd guess a lot of the power for long holes is the momentum in knocking large drill bits axially forwards and backwards. However even if it's twice as slow and inefficient, i can get 6x75mm holes from one battery, generally drilled badly at full reach, so i'm guessing at least one 250mm hole per battery should be fine.

Or would it be possible to weld two bits together?
Maybe that could work. Anyone able to do this?
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Offline phizz4

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Re: Long SDS Quick drill bit
« Reply #7 on: December 16, 2018, 09:09:36 pm »
I found this on a review of the drill on the Amazon web site. I don't know if it is useful or not?
May 2011. The Bosch UNEO 3-in-1 is a brilliant tool; it's beautifully light-weight and it's cordless (it won a design award in 2009). Yes, it only comes with a few Bosch SDS Quick drill bits, but you don't have to worry about the lack of accessories any more -- and you don't need to order accessories from Germany anymore either. Miles Tool & Machinery Centre (Yeovil, Somerset; telephone 01935 421281; [...]) sells a compact Bosch universal adapter (product number 2 608 572 075) which works with the UNEO. With this adapter, you can use all your standard drill bits in your UNEO (taking up to a 10 mm cylindrical shank).

WARNING: DO NOT buy an SDS+ adapter or SDS Plus drill bits ('Plus' means big - and any SDS plus item is too big for the UNEO). Other DIY beginners techie talk: the Uneo uses Bosch SDS Quick drill bits or it may take other bits with a hexagon shank -- it doesn't take SDS plus drill bits or HSS drill bits. REMINDER: The UNEO manual also says "use only screwdriver bits with ball catch (DIN 3126-E6.3). Other screwdiver bits can be used with a universal bit holder with ball catch."

Bosch lose a star (and they should go stand in the corner and feel shame) for not including a universal adapter in their kit, or making a larger range of SDS Quick drill bits easily available in England.

Offline Hammy

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Re: Long SDS Quick drill bit
« Reply #8 on: December 16, 2018, 09:42:45 pm »
I used to have a Uneo.

Then I had another one when the first battery conked out.

Then the second Uneo burnt out.

Now I have a deliciously powerful 36v Bosch.

I prefer the power and reliability of the 36v, though I accept that is a little heavy.

The 36v takes all manner of SDS bits.

It was £150 on EBay with three batteries and a charger.

Offline Hammy

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Re: Long SDS Quick drill bit
« Reply #9 on: December 16, 2018, 09:45:26 pm »
O

Offline Rob

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Re: Long SDS Quick drill bit
« Reply #10 on: December 16, 2018, 10:01:19 pm »
....Miles Tool & Machinery Centre (Yeovil, Somerset; telephone 01935 421281;...
Thanks, i'll make contact  :thumbsup:

I used to have a Uneo.

Then I had another one when the first battery conked out.

Then the second Uneo burnt out.

Now I have a deliciously powerful 36v Bosch.

I prefer the power and reliability of the 36v, though I accept that is a little heavy.

The 36v takes all manner of SDS bits.

It was £150 on EBay with three batteries and a charger.
Hammy, i too have some more powerful alternatives which i appreceate the power of in most circumstances. However the Uneo is small enough to fit in a daren drum and can follow me anywhere without holding me up, so it has it's place.... generally the back end of nowhere!

Also, the more modern Bosch Uneo's have removable battery units, thereby making them much more useful and future-proofed than the original Uneo which only had a built in battery.  :thumbsup:
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Offline Chocolate fireguard

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Re: Long SDS Quick drill bit
« Reply #11 on: December 17, 2018, 03:18:09 pm »
I doubt there's much friction moving powder up a hole, verses smashing the sh*t out of limestone. I'd guess a lot of the power for long holes is the momentum in knocking large drill bits axially forwards and backwards. However even if it's twice as slow and inefficient, i can get 6x75mm holes from one battery, generally drilled badly at full reach, so i'm guessing at least one 250mm hole per battery should be fine.


Yes I'm sure you are right. Overcoming friction to get the powder UP the hole will absorb a trivial amount of the available power.
But I think the greatest demand will be turning the drill bit against the friction with the hole, where the “lubricant” will be the powder.

Taking the spec of the Uneo: 0.5J/impact, max drill size in concrete 10mm, 280/900rpm, max torque 14/30Nm. The impact rate was not quoted, but the Uneo MAXX which seems similar does 0 to 5000 impacts/min.

I don’t know how the impact rate is changed – perhaps it varies according to the force applied to the drill? – but giving it the benefit of the doubt and taking 0.5J/impact with 5000 impacts/min that’s 2500J/min which is about 42J/s or 42W.

It is possible, in a rather more complicated way, to come up with an estimate for the power required to turn the bit against resistance when the drill is developing maximum torque.

The torque figure of 30Nm means that the drill is doing the equivalent of applying a force of 30N at the end of a 1metre lever to turn the bit in the hole. So at 5mm from the centre of rotation (where the 10mm drill is rubbing round the inside of the hole) the drill will be applying a force 200 times bigger, or 6000N.
Energy converted is force times distance moved (by the point of action of the force, in the direction of the force) so as the 10mm bit is turned once the work done is the force times the circumference of the bit. This will be 6000N * Pi * 0.01m or about 190J per rev.

When the machine is required to develop this maximum torque it will not be able to do its rated rpm, so on the lower speed setting of  280rpm (which I imagine pairs with the higher torque figure) the drill motor will not be developing the obvious 4.7rps & 190 J/rev or about 900W, but even if its speed is down at 1 rps (and no one would be so cruel as to persist with that, surely!) the power required to keep it turning will be well above that to deliver the maximum impact rate.

Cordless drill manufacturers don’t seem to give overall power figures, unlike mains derived drills. AC and DC motors have different operating characteristics. But a medium size corded impact drill might have a 600W motor, so I suggest the above estimates are reasonable.