Got a few options there guys cheers. Did here about trying a breezeblock to rough it up so will try that tomorrow
"Hello again gnselectricals",
Good Luck with trying that - however IF the Diamond tips are damaged / `flattened` nothing will rectify that except `Re-tipping` which would not be cost effective with a 28mm Diamond Core bit unless the Company sends Core bits away regularly for this to be done.
Having seen your message above where you mentioned that you had not used percussion - my comments below are not directed at You - just so that other `Readers` / DIYers can see what would probably happen if they did damage a Hired Diamond Core bit by using persussion when using it:
Some Years ago before large Diamond Core bits [eg. 127mm] were available to buy at a reasonable price - probably early 1990`s - I used to Hire them - there was the hire charge plus a wear charge - the Diamond tips were measured with a digital micrometer when the Core bit was hired and again when it was returned.
The wear charge was calculated by X amount per part of a millimetre - this was much more `cost effective` than buying an expensive Diamond Core bit [expensive at that time] and having to purchase another when that wore out or try to find a Company to `Re-tip` it - again expensive and I would have to send it away to have that done.
On one occasion a friend who I was doing a job for wanted to borrow the Diamond Core bit from me to cut a hole for a bathroom Vent Axia - He told me that he would be using it himself and as he was an experienced Builder I agreed - I had no need to mention not using percussion on the Drill to him - unfortunately he then gave the Core bit to a young inexperienced Labourer but he did not tell him not to use percussion when cutting the hole.
The Diamond Core bit was ruined before the young man realised that something must be wrong - the Diamond tips were `hammered` almost flat and the Hire Company wanted to charge Me the entire `wear charge` - something like 6mm X ÂŁ48.00 per millimetre - approx. ÂŁ288.00 - a lot of money in the early 1990`s for a `simple mistake` !
This was too much money to charge in my opinion - BUT - they tried to insist that if it was not paid I would be `depriving them of the wear charges that would otherwise have been produced from an undamaged Tool` - I could see their point.
I contacted the Company Head Office and negotiated that they were paid the Cost price of a replacement - my Friend had to pay [pay Me] for replacing the Diamond Core bit which from memory was something like ÂŁ140.00 - again quite expensive in the early 1990`s and the Hire Company probably inflated the cost to `Book price`.
I did `try my luck` and suggested that the situation should be covered by the Insurance aspect of the Hire charge - just as in `Accidental Damage` - but obviously they decided that `Misuse` was not covered by the Insurance - the cause of the damage to the Diamond Core bit being quite obvious to the Hire Company branch Manager and Staff.
Just a `Cautionary Tale` for DIYers / people inexperienced in the use of Diamond Core bits.
Regards,
Chris