Husqvarna has been on fire the past 12 months. First they upgraded their K 760 saw to the new and improved Husqvarna K 770 (Read about that here), then they drop the K 770 VAC saw on us. The construction industry has been waiting for one of the major power equipment companies to come out with an OSHA approved dustless option, now here it is.
The saw is pretty impressive. It comes standard with a digital ignition, improved air filtration and a retractable blade guard. These features really enhance the saws performance and the life of the saw. Dry cutting has always been a pain. with new OSHA regulations, it is almost impossible to cut dry with any diamond blade application. Now with this saw, you can cut dry and eliminate up to 90% of all dust produced by the saw and blade. This is by far Husqvarna’s best solution to slurry from concrete.
Another cool thing about the saw is that it takes 12″ diamond blades but offers the same cutting depth (almost 5″) as a 14″ blade. In turn, you spend less on diamond blades, but more importantly, the saw becomes a little more compact and easier to maneuver.
One of the challenges of cutting with the K 770 VAC is the actual vac part. You need to invest in a dust collector or come up with your own solution. The saw itself has a two foot hose that pumps the slurry out of the saw. Now you have to spend $1500 minimum to get a high quality dust extractor. A popular option from Husqvarna would be the S 26 model. Powerful and reliable.
Diamond Blades have evolved quite a bit over the past 20 years. New manufacturing processes have allowed engineers to get creative with blade design. This has significantly increased the amount of cool features diamond blades can have. One of the most important diamond blade metrics to track is cutting speed. This makes turbo segmented diamond blades one of the most interesting factors to consider with blades.
Whenever I am training a new employee I show them 5 or 6 different kinds of blades. I ask them what feature they think makes a blade cut fast, and what do they always answer? Turbo segments? Nope, they assume that cooling holes in the blade core make the blade cut fast. This is only partially true. Most turbo diamond blades incorporate cooling holes because the blades cut faster , heat up quicker and burn out. The cooling holes allow the blade to aerate and stay a little cooler, which prolongs the blades life.
The actual reason a diamond blade is considered turbo is the actual segment on the blade. Once the blade is ridged or rippled, it creates more speed on the saw. The cutting action is increased and the blade cuts much faster than a traditional diamond blade without turbo segments.
Realistically, I would estimate a turbo segmented diamond blade cuts 5%-10% faster than the same blade without turbo segments. This inevitably will cut down on the blades life. In my opinion, speed is always the way to go, I’d much rather be slicing through material fast and spend a little more, than cutting slow and saving a few bucks.
Tuck point blades are used to clear mortar joints and to prep masonry surfaces. When picking a diamond blade for this type of work, you have two main choices, a tuck point blue blaster and a sandwich diamond blade.
The most common choice is the Blue Blaster Tuck Point Blade. This is a super premium blade with high diamond content. It has .250 rim thickness. It is extremely aggressive and has strong blade life. The speed is decent but slower than the sandwich blade options.The lack of speed in comparison is the only draw back to this blade.
The other popular option is the sandwich tuck point blade. This is basically two general purpose blades stacked on top of each other. This is a faster cutting option and in some cases, is even more aggressive than the blue blaster. Sandwich blades are medium quality level, although you can get a laser welded option, but the price jumps up pretty high. Diamond blade life is a little short on this option, but speed is the main benefit.
Overall, if you want to buzz through a job and get a smooth fast cut, go with the sandwich option and maybe consider upgrading to the premium version. If you want an aggressive strong cut, go with the blue blaster. If I had to choose, I would do the sandwich.
In this corner, the NEW Husqvarna K 770 vs the old trusty Husqvarna K 760. The 760 has been an industry leader in gas cut off demo saws for a long time, but like most things, there comes a time for an upgrade. However, if you own an i phone, you know that not all upgrades actually improve the product. Below, we will talk about some of the new features and make a decision on if the upgrade is worth it. Here it is, Husqvarna K 770 vs K 760.
One of the biggest upgrades for the Husqvarna K 770 is the spring loaded, semi-automatic Smart Tension system. In short, this is a fancy term for keeping belt tension optimal. With 760’s a common complaint that the belts would loosen up and in turn, the power of the saw would weaken… Well, worry no more, because this technology is as legit as it comes. This is a huge improvement.
The other improvement I think is worth mentioning is that the diamond blade can be positioned on the right side of the cutting arm. This is huge because it allows you to cut closer to a wall. This is a very cool new feature.
As you can see from the Husqvarna saw comparison above. Most of the key specs are very similar. Like I mentioned before, the smart tensioning is the real selling point to the new saw. Husqvarna is definitely excited about the power to weight ratio, which basically means, the saw got slightly heavier, but in turn, got more powerful. Here are some of the specs:
In conclusion, I think the saw improvements are solid. With the extra power, extra saw life and claimed less saw maintenance, the 770 is an improvement on an already great cut off saw.
The segment height on a diamond blade is very important. Segment height can determine how long a blade lasts and also how efficiently it cuts into your material. there are 3 approximate heights that diamond blade companies carry diamond blades in.
The first is 8mm. This is usually sold as an economy blade. It doesn’t matter if your diamond blade is 14″ or 36″, this segment height is low and will have shorter blade life. That doesn’t necessarily mean that you can’t get a quality 8mm diamond blade, but chances are it will not have the same blade life as 10mm plus.
**** Side not on this height, diamond blade companies will use this tactic to sell you a lower priced blade at the same quality as your are currently getting. For instance, if I am offering a 14″ 12mm segment height general purpose blade for $85, a competitor will offer my customer a 14″ 8mm blade for $65, but market it as the same blade.
The second standard segment height is 10mm-12mm. This is on most mid level laser welded diamond blades. This segment height is the most popular and best value on a laser welded diamond blade. This is the safest segment height to choose.
The last segment height that is popular is 14mm-15mm. This is used on cheaper blades to increase their life or on PRO style blades or specialty blades. Bottom line is, if the segment height is higher than 12mm, make sure it is laser welded. This segment height is for maximum diamond blade life and cutting action.
When it comes to PRO concrete cutting diamond blades, there are 3 main factors to consider. How fast does the blade cut? How much life does the blade offer? What coolants will be used?
Time is money. This means that cutting speed is crucial when considering what diamond blade to choose for your job. Getting the correct bonded blade is very important. So if you’re cutting concrete, you need a soft bonded blade, if you’re cutting asphalt, you need a hard bonded blade. The bottom line is, you want to be cutting between 8 and 10 feet per minute. If you aren’t reaching this metric, get a new blade guy!
You also need your blade to last. Even if the blade is gliding through the material, it needs to give you significant life. With diamond blades, most relationships are opposites. For instance, if you are cutting lower horse power, your blade lasts longer. Or, if you’re cutting with a thicker rim diameter, for example a .187, then your blade will cut slower but last longer, refer to the chart below.
VARIABLES
CONDITION
CUTTING SPEED
BLADE LIFE
Bond Hardness
Harder Softer
Slower Faster
Longer Shorter
Diamond Quality
Lower Higher
Slower Faster
Shorter Longer
Diamond Amount
Lower Higher
Faster Slower
Shorter Longer
Segment Width
Thinner Thicker
Faster Slower
Shorter Longer
Horsepower
Lower
Slower
Longer
Blade RPM
Lower Higher
Faster Slower
Shorter Longer
Water Volume
Lower Higher
Faster Slower
Shorter Longer
Cutting Depth
Shallow Deep
Faster Slower
Longer Shorter
Material Hardness
Harder Softer
Slower Faster
Longer Shorter
Abrasiveness
More Less
Faster Slower
Shorter Longer
Aggregate Size
Larger Smaller
Slower Faster
Shorter Longer
Steel
Less More
Faster Slower
Longer Shorter
Lastly, you really want to have coolant on hand to keep your blade cutting fast and make sure it doesn’t burn out and you waste your money. There are a million different tanks and drums on the market from all the major manufacturers, Stihl, Husqvarna etc. It’s important to have good water pressure and plenty of water on hand. Without using sufficient water, the diamond blade will overheat quickly and you will risk undercutting.
In closing, from a PRO concrete cutting perspective, get a good blade from a good company and ask for references. Lastly, make sure that you will be getting at least 8 feet per minute cutting concrete with a high horse power walk behind saw.
Diamond blade terminology can be pretty confusing. There are so many different diamond blade companies (and diamond blade salespeople) that use the same product descriptions for different products. This can lead to the diamond blade rep misinterpreting what is wanted or needed by the customer. The terms we often hear getting mixed up are combo diamond blades and general purpose diamond blades.
GENERAL PURPOSE – First off, the term “general purpose” can be misleading. If I wasn’t a diamond blade guy, I would think that I could use this blade to cut anything. So, if I was cutting asphalt, and maybe a little concrete or stone, I would think shopping for a general purpose diamond blade would do the trick. WRONGO. Diamond blade companies, including us, use the term general purpose to basically market cheaper priced diamond blades. So to be honest, “general purpose” usually just means a cheap blade. Very rarely are asphalt blades in the general purpose category.
So, when do I use general purpose? – If you’re cutting concrete, brick, block or stone and you’re on a budget, go head and order general purpose. Otherwise, try and be as specific matching the application to the diamond blade you will be ordering.
COMBO – A combo diamond blade is a little more straight forward. Simply put, it cuts a combination of things. Most notably, concrete and asphalt. Here is the one thing I want to point out. Combo blades are great for crossing over from concrete to asphalt, it is what they’re made to do. When it comes to brick, granite etc, combo blades cut that too, but in my opinion, I would get a specific blade for these applications. This is based on blade life, cutting performance etc.
So, when do I use combo? – Basically, if you’re a site work, demo guy etc, spend the extra money and get yourself a good combo blade so you don’t have to worry about switching blades on and off.
How to choose asphalt or concrete? Deciding what material to go with for your driveway construction project is obviously an important decision. For commercial or residential driveways, how to choose asphalt or concrete will be the first question you have to answer. The scope and cost of your project will obviously dictate which direction you will go in, but understanding the materials is important too.
Asphalt Pro’s
CHEAP .. Asphalt driveways are about half as expensive as concrete driveways
Asphalt can be laid quick. Usually, it doesn’t take more than a day or two to get a residential driveway taking care of. Commercial asphalt paving will depend on the size of the area needing the work.
Asphalt is very durable. It can handle ice melting products or even withstand a poor installation job.
Asphalt has low maintenance costs. Repairs are short money and easy to mask cosmetically
Asphalt Con’s
Asphalt Longevity is shorter, 12-20 years on average
Concrete and asphalt are both great options to go with. As far as look and maintenance are concerned, I think asphalt is overall the better material to pick. If you need the driveway to be more permanent, and by permanent I mean lasting 30 years, then the extra cost for concrete is worth it. What do you think?
One of our long time customers has a job removing the surface for an MDC ice rink in Boston MA. They are cutting through about 5 inches of concrete that has the piping underneath that is needed to keep the ice in skating conditions. So think of this application as concrete with rebar on steroids.
The saw is 65 horse power, so having a high quality diamond blade is a top priority. In this case, he is using a Bone Crusher 14″ x .120 with 13mm segments specifically bonded for high speed cutting. The piping is stacked every 6 inches or so. The bond on the blade needs to be super soft to allow it not only slice through the concrete, but also get through the pipes effectively and without binding.
This is a difficult application. Experience and high quality products are essential for getting this job done safely and on time.
Contractors, particularly site work guys, are always short on time. The last thing they want to do is switch out a diamond blade every time they go from cutting concrete to asphalt. On top of that, they don’t want to spend money on 6 different diamond blades to cut 6 different things. Concrete, Asphalt, Granite Curb etc. If you bought a specific blade for each application, you’d go out of business. Unfortunately, the best bang for your buck does in fact put you cutting asphalt with asphalt specific blades and cutting concrete with concrete specific blades etc. BUT! There is an alternative. The combo diamond blade!
When you cut hard stuff, concrete for example, you need a soft bonded diamond blade. When you cut soft stuff, like asphalt, you need a hard bonded diamond blade. I won’t bore you with the science of this (I do that in previous blogs) but obviously having a blade on hand that will cut both concrete and asphalt effectively is extremely beneficial.
There are two attributes about a diamond blade that makes it able to be used effectively as a combo:
Medium bond. This lets the blade cut either material and not minimize the life.
Drop segments. These prevent undercutting when being used on an asphalt application.
Overall, combo diamond blades are a little more expensive. If you are a contractor that simply is not going to take the time to switch around blades when going from cutting concrete to cutting asphalt, then the extra investment is well worth it.
