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How are your saw blades sharpened?

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Forum topic by bigblockyeti posted 04-04-2014 08:34 PM 742 views 0 times favorited 14 replies Add to Favorites Watch
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bigblockyeti

1738 posts in 444 days


04-04-2014 08:34 PM

I have two go to places that I have sharpen my 10” blades. The closest one is cheaper and does a decent job, but sometimes has a long back log. The blades always come back very sharp and they grind the sides and back of each tooth, but not the face. The second place does ok, they cost more and they only grind the face of each tooth. Though it looks like they’re putting forth less effort, both blades will cut very much the same. So, is one way right and one way wrong, how are yours sharpened?


14 replies so far

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knotscott

5566 posts in 2099 days


#1 posted 04-04-2014 08:50 PM

I thought they generally only sharpen the face and top…..sharpening the sides changes the overhang dramatically, which changes the performance of the blade.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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SCOTSMAN

5538 posts in 2309 days


#2 posted 04-04-2014 09:26 PM

I agree with K Sccott, as this would alter the tooth geometry and do a disservice imho.You should never touch the sides as it is designed to capture the right kerf arrangement for future cutting Alistair

-- excuse my typing as I have a form of parkinsons disease

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bigblockyeti

1738 posts in 444 days


#3 posted 04-07-2014 03:01 AM

I do know that each tooth would be ground slightly thinner each time, but clearance between the tooth edge and the plate, as long as such clearance still exists, hasn’t yet been a problem. The hook angle stays the same and the geometry changes, though present seem subtle enough to not represent a real problem.

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DrDirt

2542 posts in 2466 days


#4 posted 04-07-2014 03:07 AM

I have only sharpened 2 blades and I sent them to Forrest.

The thing with grinding the sides, is now you don’t cut 1/8 inch wide slots anymore. So I think the guys doing ‘less” work are trying to maintain your full width, and not have to retune your tablesaw measuring tape crosshair each time.

If you have 1/8 stock that you use as box splines for corners, getting your Narrower blade back might be a real PITA.

As it also would mess up other joinery jigs, like if you have a box joint jig.

-- "If we did all the things we are capable of doing, we would literally astonish ourselves." Edison

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NiteWalker

2710 posts in 1300 days


#5 posted 04-07-2014 04:21 AM

I use cheap $20 blades (but are rated very good) so when they dull I toss them in the old blade drawer and buy new.
It’s useful having old blades around for cutting things not normally cut with a good blade like aluminum or reclaimed lumber.

-- He who dies with the most tools... dies with the emptiest wallet.

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bigblockyeti

1738 posts in 444 days


#6 posted 04-07-2014 12:34 PM

Hadn’t thought about the need to recalibrate everything for the adjusted kerf. Many of my blades have a new kerf of 0.118” and after measuring one that had been sharpened once on the sides, the overall kerf was 0.0045” less. I’m not going to try to adjust the hairline on my fence 0.00225” to the left, I usually leave that kind of precision to metal working. Most of the jigs I have I use a stacked dado set with, so far that hasn’t yet needed to be sharpened. I’m thinking I may need to establish a more objective test as to exactly which performs better just after being sharpened. Then again maybe I just need to buy one of the Harbor freight blade sharpeners and see how it works.

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knotscott

5566 posts in 2099 days


#7 posted 04-07-2014 04:30 PM

Unless you’re not fussy about your blades, I’d skip the HF sharpener. I’d never attempt to put a high quality precision blade on the HF sharpener, and IMO lesser blades aren’t worth spending money on in the first place. When ~ $30 can buy a good blade delivered to your door, why mess around?

http://lumberjocks.com/knotscott/blog/36699

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View bowedcurly's profile

bowedcurly

495 posts in 453 days


#8 posted 04-07-2014 04:41 PM

the guy that sharpens my blades does all 4 sides, and does a really good job, I bought a forrest ww2 off ebay for 25.00 and took it to him he done all 4 sides and it cuts very good, didn’t know about not having only 1 or 2 sides bein sharpened, going to keep that in mind next time I go

-- Staining killed the wood<<<<<>>>>>Dyeing gave it life

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MrRon

2933 posts in 1967 days


#9 posted 04-07-2014 05:06 PM

Bigblockyeti,

Do not choose the closest sharpener again; he doesn’t know what he is doing. The second place thinks a face grind is adequate which it probably is. Too much top grinding reduces the clearance angle with the steel plate behind each tip. The only time you grind the sides is when a tooth (or teeth) has to be replaced and grind only the tip that was replaced to match the other teeth. Normally, you grind the face and the tops in that order. If tips are replaced, grind the face, sides and top in that order.

Sharpening blades requires a precision that a cheap sharpener can’t achieve. Good blade sharpeners cost in the 5 to 6000$ range. I have a high quality sharpener, so have never used the HF model. I would be very doubtful if it could do a good job.

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MrRon

2933 posts in 1967 days


#10 posted 04-07-2014 05:12 PM

bowedcurly,

Side grinding is totally unnecessary, unless tips are replaced and then only the replaced tips are side ground to match the other teeth. If you side grind all the teeth, you will reduce the kerf and may get to the point where the kerf equals the thickness of the steel plate (not a good thing). What I’m hearing from these posts is: these saw sharpeners don’t know what they are doing. There is a right way and a wrong way. All I’m hearing is the wrong way. There are still some skilled saw sharpeners out there, but few and far between. Forrest probably has some of them.

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bowedcurly

495 posts in 453 days


#11 posted 04-07-2014 10:52 PM

I just went outside and mic’d my blade still at .125 124.50 124.25 125.20 I sat and watched the guy do all 4 sides took him like 20 minutes or longer can’t remember but it took awhile but the blade is still in spec but next time will have him only do the front & top or just top thanks for your input, opened my eys

-- Staining killed the wood<<<<<>>>>>Dyeing gave it life

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MrRon

2933 posts in 1967 days


#12 posted 04-08-2014 05:20 PM

bowedcurly,

Just curious as to how you could measure the width of the teeth with a micrometer. The teeth are offset to either side of the plate so the width of the tooth does not equal the width of the kerf. You have to measure from the tip of one tooth on one side of the plate to the next tooth on the opposite side of the plate; something that can’t be done with a mic. There is a tool (I have one) that takes a measurement from the tip to the plate. You do this on both sides and add the thickness of the plate to arrive at the kerf width. Sorry for all the explanation. I used to sharpen saws for a living, so I’m pretty informed about cutting tool geometry. I will try to answer any questions you have if I can.

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MrRon

2933 posts in 1967 days


#13 posted 04-08-2014 07:14 PM

This link is a sharpening service that charges around $20 per blade. They sharpen top and face on 5-axis grinding machines. I have not tried them, but they appear to be high quality. http://www.ipgandm.com/Circular-Saw-Blade-Sharpening/products/448/

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Dutchy

581 posts in 892 days


#14 posted 04-08-2014 07:34 PM

Never side grinding !! Are you sure they did side grinding.

Look at

http://www.leitz.org/betriebsanleitungen.html?lang=en

and choose PDF document Kreissägeblätter bestückt (Circular sawblades)

In this document you can also find the englisch explenation (Sharpning 1.5 and 1.6 especially 1.6.2)

See also pages 68 in this document and you see how resharpning has to be done

Succes

-- My englisch is bad but how is your dutch?

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