[Rockhounds] Diamond Saw Blade Repair

[jb]

Kreigh Tomaszewski wrote:
> Tom,
>
> Think about how you straighten a bent nail. You place it on a hard 
> flat surface with the bent portion sticking upright, and you hit it 
> with a hammer. If you hit it too hard you get a reverse bend and have 
> to rotate it and try again.
>
> Place your blade on a hard flat surface with the bend sticking up. 
> Working in a spiral pattern tap the parts sticking up with a large 
> flat-head hammer. Concentrate around the high points, but don't hit 
> too hard. With patience you can flatten it back out.
>
> Kreigh
>
>
>
> On Thursday, Apr 16, 2009, at 22:59 America/Detroit, Tom Bowers wrote:
>
>>
>> I recently acquired a used 18" rock saw at the best of prices.  The 
>> blade on the saw is not straight, slightly bent.  Does anyone know 
>> where (or how on my own) I can get the blade straightened?
>>  
>> Thanks for your help,
>>  
>> Tom
>>
>>

Note that concrete is usually *not* a flat enough surface; try to find a 
rather large flat piece of iron or steel to work your blade. And the 18" 
blade is rather thick so will take harder blows to straighten. But this 
also means that too hard a blow will bend the metal too far.  This shows 
up as small high spots on opposite sides of the blade which will drag 
and burn when it is used.  Work both sides of the blade alternately from 
the center in a spiral motion out to near the edge; don't try to 
straighten the whole thing at one go. Little by little is the best 
approach. Avoid hitting anywhere near the center hole as this should 
always fit squarely on the shaft to prevent vibration. Presumably it has 
been securely braced when used and is not bent in that area anyway.

As Kreigh said, it takes a lot of patience and a certain knack to 
accomplish a decent straightening. If you use a heavy hammer, use a 
lead-filled dead-weight one to keep from concentrating the blow in too 
small a place. Avoid hitting too close to the rim as that will bend over 
the edge of the kerf slightly and ruin the effect of straightening the 
rest of the blade (uneven wear of diamond from one side or the other). 
You will know when you have "gone too far" as the blade will "dish" and 
spring from one side to the other ; only heat treating will cure that.

Places like Diamond Pacific will straighten a large blade, but I don't 
know what the costs are, certainly less than the cost of a new blade.  I 
am sure a skilled blacksmith could also do the job. Then again, examine 
closely the diamond rim. It may be that there is not enough life left in 
the blade to put much work into it in the first place.



john