Best SDS drill bits for drilling a lot of granite for the money?

[kez1]

I'm cutting lots of granite with wedge and feather shims.
For this I'm drilling lots of holes in the granite with SDS masonry drill bits.
I'm getting through a lot of drill bits.

Which are the best durable SDS granite drill bits that will stay sharp for the money?

 

[blup]

I've used dewalt bosch - and Makita - and all have been good quality.

Blup

 

[Deleted member 174758]

You need to look for a 3- or 4-flute design if at all possible - Bosch, Heller, Hilti, DW, etc

 

[kez1]

You need to look for a 3- or 4-flute design if at all possible - Bosch, Heller, Hilti, DW, etc

I got some un-fluted Bosch "SDS Plus-3" carbide tipped drills this morning and drilled three 12mm holes each 4" deep before the bit packed in.
It was about £4 from toolstation.
I previousy tried stopping to let the drill bit cool down, then also tried pouring cold water on the hole.
Neither seemed to made a difference to longevity.

I looked up 3 and 4 flute carbide tips.
They seem to let the cut particles clear out of the hole more easily meaning already cut particles don't get cut twice or more often. Apparently this causes much less wear/ tip bluntening.
3 /4 flute carbide tips are much more expensive costing about £60 from what saw with a quick google.
The Bosch SDS single tip carbide drill I was using this morning costs £4.
£60 / £4 = 15.
Does the 3 /4 flute drill bit last 15 times longer?
Any specific recommendations on supplier /price.

 

[Deleted member 174758]

Comparing engineering mills to masonry bits really won't get you very far, I'm afraid. They have completely different cutting actions (an SDS drill is literally a hammer which strikes to chip away the material then rotates to remove the waste up a spiral flute).

4in/100mm holes, try these Heller TriJets @ £11.33 each (incl. VAT, but carriage extra). Want to go deeper, then the same people also sell bits to do 200mm deep holes at £16.30 each (incl. VAT, but carriage extra). Even Amazon are doing a full set of 7 no Trijets (5/6/7/8/19/12mm) at £46.27, so who quoted £40? There are other bits around, but I find the Hellers pretty good, especially at the price. Price isn't everything - 3- and 4- flutes bits run cooler and drill faster and so drill straighter than cheaper 2-flute designs.

 

[kez1]

Comparing engineering mills to masonry bits really won't get you very far, I'm afraid. They have completely different cutting actions (an SDS drill is literally a hammer which strikes to chip away the material then rotates to remove the waste up a spiral flute).

4in/100mm holes, try these Heller TriJets @ £11.33 each (incl. VAT, but carriage extra). Want to go deeper, then the same people also sell bits to do 200mm deep holes at £16.30 each (incl. VAT, but carriage extra). Even Amazon are doing a full set of 7 no Trijets (5/6/7/8/19/12mm) at £46.27, so who quoted £40? There are other bits around, but I find the Hellers pretty good, especially at the price. Price isn't everything - 3- and 4- flutes bits run cooler and drill faster and so drill straighter than cheaper 2-flute designs.

Thanks. I got a Heller Trijet on ebay at this link.