Saw blade question.

[Cheesehead]

I've been cutting my bricks on my old table saw. I got an MK diamond blade. It worked great for cutting & tapering about 50 bricks.

Now, I'm assuming it's dull, I can't cut worth a *&^%$&&.

Question - is this normal? Did I force them through? Should I just break down and buy another two blades, or is there another brand/type that would be recommended?

[Tscarborough]

Re: Saw blade question.

No, when cutting with diamonds, they do not get "dull", the matrix either doesn't wear or wears too much. As a general rule, when cutting soft material, to "sharpen" the blade, cut something hard (like a regular brick or a chunk of concrete. When cutting something hard, cut something soft.

[Faith In Virginia]

Re: Saw blade question.

I went through 4 diamond blades and that was with water cooling. so I say yes buy some more. Every time the outside layer of the blade is gone you will know it's time to replace the blade because that is where the diamonds are. They aren't like a regular saw blade so they don't get dull. But they do wear down like the black cutting wheels for block or metal. You will need more.

[Cheesehead]

Re: Saw blade question.

No, when cutting with diamonds, they do not get "dull", the matrix either doesn't wear or wears too much. As a general rule, when cutting soft material, to "sharpen" the blade, cut something hard (like a regular brick or a chunk of concrete. When cutting something hard, cut something soft.

So you're saying I should try to cut a piece of concrete to see if I can rejuvenate the blade?

[Tscarborough]

Re: Saw blade question.

It will rejuvenate the blade by removing matrix and exposing fresh diamonds. Technically, you should buy the correct blade for the material you are cutting, a blade for firebrick will have a medium strength matrix, since firebrick are very soft, but also somewhat abrasive. If you have a concrete blade (which is what my guess is you have), the fire brick are not hard enough to wear the matrix properly.

[dmun]

Re: Saw blade question.

Yes, blades do wear out. I've worn out a bunch of them. They wear out a lot faster when the cut isn't flooded with water. I trust you're protecting your lungs with a good respirator when dry cutting?

[Tscarborough]

Re: Saw blade question.

Wearing out is not the same as becoming dull. When it is worn out it is obvious, as there is no more segment left. If there is segment left, it is not worn out.

[Cheesehead]

Re: Saw blade question.

Tscarborough - thanks for the suggestion. Cutting a brick allowed me to... cut one more firebrick. Or maybe two, before it just bogged down again. The blade I have is for brick and concrete (gave a link at the start), would there be a better suggestion?

dmun - a big yes on the respirator, earplugs, glasses, leather gloves... my kids make fun of me. But when the other members of the household start yelling at me for something they think I need to do, I can point to my ears, shrug my shoulders, and go back to my work.

[Cheesehead]

Re: Saw blade question.

Other possible blades?

Amazon.com: MK Diamond 150680 MK-950D 10" Dry Cutting Turbo Rim Premium Blade for soft abrasive materials: Home Improvement

Amazon.com: MK Diamond 158358 MK-625D 10-Inch Dry Cutting Continuous Rim Saw Blade with 5/8-Inch Arbor for Masonry: Power & Hand Tools

[Tscarborough]

Re: Saw blade question.

Cut something hard until you can see the diamonds.

[brickie in oz]

Re: Saw blade question.

So you're saying I should try to cut a piece of concrete to see if I can rejuvenate the blade?

The professional brick cutters here run the blade through a piece of old hard mortar.

When cutting hard bricks they slightly melt and deposit a glaze on the blabe, running it through the dry mortar removes the glaze.

[Faith In Virginia]

Re: Saw blade question.

I think if he is cutting on a table saw and not a tile saw then he would be burning through blades quickly if not having water to do it's thing. I did a quick thing so look at my picture and if your blade looks like the right side of my picture you need a new blade. If you have some of the "rough stuff" left you will need to de-glaze the blade. Hope this helps

[Cheesehead]

Re: Saw blade question.

I think if he is cutting on a table saw and not a tile saw then he would be burning through blades quickly if not having water to do it's thing. I did a quick thing so look at my picture and if your blade looks like the right side of my picture you need a new blade. If you have some of the "rough stuff" left you will need to de-glaze the blade. Hope this helps

Definitely got a lot of "stuff" left on the blade, about a quarter inch that has diamonds embedded. And it cuts concrete, and limestone, just not firebrick very well.

Sounds like it's the de-glazing route. I've got some old chunks of mortar & concrete around here that I'll try running through in the morning. If nothing else, I was planning to cut pieces of limestone for the decorative outside arch, I might start cutting that.

I know a tile saw is recommended, but the old cast-iron table saw is what I've got, so I figured I'd give it a go. Worked really well... up until this afternoon.

[Tscarborough]

Re: Saw blade question.

Does the blade show signs of rainbowing?

[azpizzanut]

Re: Saw blade question.

Hi All,

Diamond Saw Blade 101

Here is how to tell if the blade is worn out. Look at the working edge with magnification. If you see the steel core and no diamonds on it then its worn out. There may still be diamonds on the sides of the rim but that is not where the work is done.

Some types of diamond blades are notched and the notches are filled with brazing metal and diamond grit. The notches are only so deep. When they wear down and nearly disappear then the blade is worn out. You may notice an uneven wear pattern because the arbor was not true and one edge of the blade got more action per rotation.

Diamonds do wear out too. Diamonds get chipped and knocked out of their metal matrix and often the blade metal will glaze over the diamonds causing it to slow its cutting ability. This usually happens when cutting very hard material. Diamond blades contain various size diamond grit from fine to coarse depending on the intended purpose of the blade. A small diameter gem sawing blade contains fine diamonds. Larger diamonds are used for rock and masonry. Premium blades usually contain a higher concentration of diamonds than less expensive blades.

Would you like to know how a raw diamond is cut and polished before it is placed in a setting? It is cut with other diamonds. Professional diamond cutters use huge, flat, iron disks divided into several circular segments. They rotate horizontally on a table with a motorized arbor. Fine diamond grit called boart is placed near the center, then the next coarsest grit, etc. (You wouldn't want to place the coarse diamond grit near the center of the wheel because centrifugal force makes it migrate to the outer edge thereby contaminating other segments). Placing the fine polishing boart near the center doesn't affect the larger grit in the outer segments. Up to four diamonds can be polished at a time on the same large disk, in some shops, each one in a different stage of cut/polishing. In the example I saw it took about ten hours to facet the diamond.

Cheers,