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What are cool blocks?

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Forum topic by Purrmaster posted 03-08-2014 09:37 AM 1199 views 0 times favorited 11 replies Add to Favorites Watch
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Purrmaster

914 posts in 1556 days


03-08-2014 09:37 AM

Once my tax returns come in I might be getting the Grizzly G0555 bandsaw. From what I’ve read it seems there are a lot more upgrades/accessories needed on a bandsaw than a table saw.

I keep seeing references to some product called cool blocks. People seem to find them every necessary but I have no idea what they are or what they do.

Could someone please enlighten me?


11 replies so far

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Minorhero

372 posts in 2068 days


#1 posted 03-08-2014 12:22 PM

Cool blocks are the blade guides on a bandsaw. There are ones above the table and a below. They will keep the blade running true and thus they will occasionally (or frequently depending on how well tuned your bandasw is) touch the blade sides while moving. This creates friction which heats up the blade which causes snaps or to mess with the temper which causes blades to dull faster. So your cool block should be made of material that doesn’t heat up easily or at least leeches the heat away from the blade.

More expensive blade guides use bearings instead of blocks and spin instead of rub against the blade.

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Wildwood

1882 posts in 1598 days


#2 posted 03-08-2014 12:23 PM

Band saw blade guides!

G0555, uses ball bearing blade guides! Would have to modify the band saw to use cool block blade guides.

-- Bill

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Purrmaster

914 posts in 1556 days


#3 posted 03-08-2014 09:43 PM

Thank you!

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Mip

446 posts in 1541 days


#4 posted 03-08-2014 10:08 PM

Way back when, I used to work in a tool store that sold these. What they are is laminated plastic blocks that replace the metal guide blocks that are standard on new bandsaws. The metal blocks are pulled back the thickness of a piece of paper so they don’t touch the blade and build up heat; cool blocks can actually touch the blade to guide it. You don’t want to put an excessive amount of pressure on the blade with the blocks when you set them up; they’re not as fussy to set up as metal blocks. Come to think of it, I think they were impregnated with graphite powder which makes them slick. They come in different sizes to fit a lot of makes of bandsaws. A lot cheaper to use than guide bearing setup like the Carter system.

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MrUnix

4224 posts in 1662 days


#5 posted 03-08-2014 10:48 PM

The ‘heat’ thing is well overblown.. Jim Mattson over at the Woodworkers gazette did a comparison of the various bearing type guide solutions available and as part of that, he did a test to find out just how much ‘heat’ could be generated. From the article:

  • To test the effects of heat, I picked the gnarliest looking blade from my pile and mounted it on the saw. Fully expecting this test to ruin the blade, I threw caution to the wind and tensioned this puppy well beyond the limits I normally observe. It was tight! The test was simple: back off the bearing from one side at the top assembly and shove the opposite bearing as far out of alignment into the blade as possible. Turn the saw on…. for an hour or two….while I did something else…..fully expecting to hear that BANG when the blade breaks from …. whatever.

Conclusion?

  • It didn’t happen. In fact, all three bearings came through this test with flying colors. Even when I turned the saw off and touched the bearings, one would have expected them to be too hot to touch. Not so. Lukewarm maybe but not even close to hot. There wasn’t any need to get out my atomic powered digital thermometer. Heat just wasn’t going to be an issue. Since the bearings were so cool, I imagined it possible the 3/8” blade may have acted to draw some of what little heat was created away from the bearings with the rest being absorbed by the air and the bandsaw. It’s hard to say.

Then he tested the stock steel blocks:

  • To find any advantage for the bearings, I tried the same test on one of my steel guide blocks; it too was tightened hard into the blade. Oddly, and completely by surprise, the result was the same plus my old blade was getting a pretty nice polish on one side thanks to it’s constant contact with the steel. It started to look new again…:)

Unfortunately, he didn’t test ‘cool blocks’, but based on my own experience, which Jim reinforces in his article, if ‘heat’ is not an issue with steel blocks in a worse case scenerio, cool blocks, apart from their name, don’t offer any real advantage.

Link to the article: http://www.woodworking.org/WC/GArchive99/2_24matband.html

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Wildwood

1882 posts in 1598 days


#6 posted 03-09-2014 12:11 AM

Several years ago folks with G0555, were swapping out their blade bearings with guide block so could run thinner blades (1/8”, & 3/16”). They ordered parts from Grizzly that came from a band saw that used blocks.

Have not heard of that being done in a long time. Think folks wanting to run those thinner blades ordering a Carter set up these days whether have a Grizzly or other Band saw. Since have blade bearings on my band saw would not try going smaller than a 1/4” blade.

Whether band saw has guide blocks or blade guide bearing best to set them up following instructions in the manual. I think guide blocks or guide bearing will serve you well 99% of the time without modifying your band saw.

-- Bill

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Purrmaster

914 posts in 1556 days


#7 posted 03-09-2014 02:03 AM

Carter setup?

View OggieOglethorpe's profile

OggieOglethorpe

1212 posts in 1573 days


#8 posted 03-09-2014 02:28 AM

Be aware that solid blocks can often be better if you’re cutting green or pitchy / resiny wood.

I have Carter bearings on my saw, and they’re great for clean lumber. Solid blocks, (steel / cool / maple) scrape the blade, while bearings pack debris on, steamroller style. If enough debris sticks to a blade, bearings can get weird in a hurry.

If you change from one type to another, always save the old setup, as there may be situations where it’s best. No setup works best in every situation.

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Purrmaster

914 posts in 1556 days


#9 posted 03-09-2014 03:54 AM

So what makes cool blocks different from any other hunk of metal?

View OggieOglethorpe's profile

OggieOglethorpe

1212 posts in 1573 days


#10 posted 03-09-2014 01:14 PM

Cool blocks are a graphite impregnated material, possibly fiberglass.

In my experience, they’re quieter than metal blocks, harmless to the teeth of narrow blades, and you can run them right against the blade.

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Wildwood

1882 posts in 1598 days


#11 posted 03-09-2014 01:48 PM

Boils down to size to fit your band saw cost. Cool blocks good choice when replacing OEM metal guide blocks.
Make sure buy size that fit your band saw.

If do search for cool blocks will find them made from different materials. Latest next big thing in cool blocks is ceramic. Many owners make their own cool blocks out exotic woods or oil soaked hardwoods.

-- Bill

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