Saw sharpener

[Steve Jones]

I saw the saw sharpener just introduced by Harbor Freight the other week, cheap and I'm tired of paying through the nose for blades that come back from the shop sharp but that last about half as long as new ones, I'm also tired of buying new blades (well, my wallet is).

Ok, it's cheap, nasty, Chinese technology (you'd think I'd have learned by now) but as far as my research has gone, the alternatives (good US built tools for the same job) are in the thousands (not practical, this is the only option).

So I brought one, played with it the other evening, not impressed, I neatly trimmed all the teeth as per the truly lousy instructions, put it on the saw, nope, no better than when I started. Tried the other wheel that comes with it with the same results...

Then I did some more research, found some machinist board where some guy loved this thing, he posted a tutorial with pictures showing his setup, first thing I see is that he left the cap off the cover of the grinding wheel (that's the only way you can get the whole tooth front to touch the wheel stupid! duh).

He also mentioned that the best way to make sure you get the same angle as originally ground was to mark your first tooth (so you know when you're done) with a black marker and then paint the whole front of that tooth with the marker, grind than one a little and if you remove the ink your aligned perfectly.

Also I learned to clean the blade with a good cleaner made for the purpose. and only use the diamond wheel (the thin one)

Setup carefully and sharpened six Festool blades that evening in about an hour - wow! this sucker works - in fact it's a piece of cake - I left off the cover and in the end removed the little stop post thats supposed to stop you grinding too much off, if you hit each tooth with the same pressure for the same time (gently for about a second) you get perfect results and easy setup.

The gadget cost $59.99, The sharpening service charges about $20.00 per blade, I saved $60 that night.

Consider buying one of these things, it sharpens pretty much any sized blade you're likely to have in the shop. Nice to be able to "touch up" that special blade before hacking into some special expensive piece of hardwood.

Now this is not Festool quality stuff, it's cheap and tacky, but it works - it's already paid for itself twice over in my shop.

 

[danrush]

Hey Steve,

Looks promising.  Would you guide us towards that tutorial?

Thanks, Dan

 

[Steve Jones]

Dan,

Tried looking for that tutorial again this morning, can't find it. I'll try again later but basically I had included everything I learned from it in the first posting (leaving off the guard and the black marker trick)

Steve

 

[John Stegall]

I agree about the sharpening services I have used and the shorter service life. I also hate it when my planer blade comes back hollow ground. That problem I solved by mounting both blades at opposing angles and using a DMT diamond stone. I will have to look at one of the HF jobbies the next time I go to San Antonio.

 

[Steve Jones]

John,

I use the the same diamond stone for my planer blades, I think the setup would be tough to get exact on the little sharpening machine (it mounts circular saw blades with a simple tapered insert that centers them perfectly) straight blades would be asking too much of the tool I think.

The diamond stones work great, I brought the largest size and simply balance them on the cutting face and count strokes (to keep both blades equal) I'm not sure this would work for the entire life of the blades, but I'll live with shorter service life and extra expense for the convenience - I keep them touched up but if (and when) one ever chips then the pair will be scrapped or sent to a professional (but then the same applies to the circular blade with a missing tooth - you'll find it when sharpening on the machine - even if you're not paying attention and looking you'll hear when a missing tooth hits the grinder.

 

[Kevin Johnson]

Based on the review, I went out an purchased one a Harbor Freight saw sharpener on Sat.  I needed a new blade immediately or I needed one of the 2 that I had sharpened.  I figured for the cost of another Festool blade, if the thing works it would more than pay for itself. 

I know nothing about sharpening blades, so I was a little nervous at first.  I decided to practice on an old Dewalt circular saw blade that I had.  I did manage to grind off one tooth on that blade, but eventually I got the hang of it.  I put the blade in a saw and it cut well.

It was now time to try out the Festool blade.  However, the Festool blade's geometry is quite different from the Dewalt.  There is a compound grind on the tips of the Festool blade.  One part of the tip is ground at 15 degrees and another side is  ground at 5 degrees.  I wish that I could say that I successfully sharpened the blade, but I was not able to.  I guess it will require more practice.

 

[Steve Jones]

Kevin,
I found just touching up the face of each blade worked fine for me, the faces are all perpendicular the side of the blade, in other words the motor and grinding wheel are set flat.

You can grind the top of each blade but to do that you need to set the angle and do every second tooth, then re-set to to the rest, I found I got good results with just touching up each face. Maybe after several sharpenings I'll need to send the blade in for a professional sharpening, but I'll still end saving a lot of money with this gadget.

 

[Steve Jones]

Dan, It's been a while, but I finally found that thread about the Harbor Freight sharpening machine:

http://www.hobartwelders.com/weldtalk/showthread.php?t=30331

Hope this helps

 

[Dave Ronyak]

Thanks for the link.  It's a joy to be linked to a forum that you don't have to join in order to see the photos!!  I've never tried to sharpen a blade other than a little handhoning with a diamond faced stick, but this machine looks very encouraging. 

Are there any limitations preventing use of the HF device on 160mm blades used by Festool?

Dave R.

 

[Steve Jones]

Dave,

no limitations, the machine will work with just about any size circular blade, blades mount on a movable arm with a tapered clamp in the center (tiny version of those clamps they put your auto wheels on at the tire places).

The trick is to set it correctly for the various angles on the teeth to hit the grinding wheel correctly, this is simple trial and error but is simplified by painting the face in question with a black marker and testing (if all the ink is removed evenly you're set perfectly).

Definitly practice on a blade you don't cherish first! it's easy to screw up before you get the hang of it, but after one or two tries it becomes pretty simple to set up for any blade. (even the tricky ones that switch angles with each alternate tooth) do each second tooth then flip the blade and re-set the angle the other way.

Lots of things could be improved on the little machine (my improvements so far have been limited to tossing the parts that get in the way) IE:
* Grinding wheel cover (in the way for smaller blades like the Festool ones)
* Ratchet post (or whatever they call it, it's supposed to stop you grinding too much off any one tooth, but it takes way too much time and fuss to get it to work)

Now since I'm only gently grinding on the face of each tooth, I always knew that I'd still have to contribute to the "new truck" fund at my local blade sharpening service. So in the interests of scientific experimentation I sent half of my blades off to the sharpening service last week, got them back yesterday. I'm interested to find the difference in life between "home sharpened" and the professional ones.

 

[nickao]

What is the difference in freshly sharpened from you compared to freshly sharpened from being sent in?

 

[Dave Ronyak]

Thanks, Steve.  I thought use of some stop is important to removing the same amount from the face of each tooth.  I'm guessing "kiss grinding" a wee bit off each tooth of a blade is OK for a blade to be used for rough cutting tasks, but skeptical of my being able to do an adequate job on a blade intended for finish woodworking, e.g. my Festool 28T and 48T ATB blades, and my 10" Tenyru Gold Medal blades.  Those need to be precisely ground to do their intended cutting work.  Please clarify how you grind the teeth uniformly.

Among my experiences is one with a great father/son sharpening shop.  The father even designed and obtained some patents on his blades.  They were both true artists and craftsmen at their work.  I remember the son challenging me to buy two new blades and to bring in one of them to sharpen to prove their finished product was better than the factory.  I did so using a pair of standard chrome plated steel 10" combination blades from Shopsmith.  With the one they sharpened, in one afternoon, I was able to rip over 600 BF 1 1/4" thick KD red oak into groups of strips of 5 1/2", 4", 3" and 2"  widths for conversion into "ranch plank" style flooring.  The blade was still cutting well at the end of the run.  That Shopsmith has only a 1 1/8 HP motor.  I really miss those men, both are deceased, and shop long gone.  In contrast, the factory sharpened blade would be dragging and showing evidence of overheating near the tips of its teeth after about half that amount of ripping.

Dave R.

 

[Daviddubya]

Do you guys really think it is wise to use a Harbor Freight machine to sharpen a Festool saw blade?  Or any other expensive saw blade?

 

[nickao]

If Festool put out an identical machine and it said Festool on  it, then would you use it? The Harbor Freight name has nothing to do with it.

I submit where you buy it and who makes it and the cost is irrelevant if it works.

On at least three web forums people are having great experiences getting this particular machine to work and work well.

So yes it is not only wise, but cost effective after just two or three sharpenings it's paid for.

 

[Daviddubya]

If Festool put out an identical machine and it said Festool on  it, then would you use it? The Harbor Freight name has nothing to do with it....

In a word - NO.  I would not attempt to sharpen a saw blade myself.  And I would not use anything with the Harbor Freight name on it.  I have bought from Harbor Freight a number of times and been disappointed every time.  Their stuff is junk in my experience, especially anything with a motor on it.

I read a thread at another forum discussing this sharpening machine.  The advice of the professional people was to steer clear of it.  Unfortunately, I cannot locate that thread now.  Oh well.

I take my blades to a local pro sharpening shop.  Most of my blades cost close to $100, some more.  No way would I trust a Harbor Freight machine to sharpen my blades.

 

[Steve Jones]

I can see the advantages of categorizing to help keep the world simple to understand...

After all. Once you decide that all people of a particular color are naturally lazy, and then those people of another color are dishonest.

Doesn't that makes things so much simpler! no need to worry about the odd exceptions, judge everything and everyone by it's color or brand.

That kind of logic keeps folks from saving money to spend on more good tools.

(and keeps some wasting on it atrocities like the Krapex)

 

[danrush]

Steve,

Thanks for the referral.  I did pick up the sharpener, and although the learning curve for me was a bit tedious, I am happy with the machine.  I go through a ts55 blade a job (about a week) , which I would then send out for sharpening, so you can imagine the savings.  Thanks again.

Dan

 

[Daviddubya]

I can see the advantages of categorizing to help keep the world simple to understand...

After all. Once you decide that all people of a particular color are naturally lazy, and then those people of another color are dishonest.

Doesn't that makes things so much simpler! no need to worry about the odd exceptions, judge everything and everyone by it's color or brand.

That kind of logic keeps folks from saving money to spend on more good tools.

(and keeps some wasting on it atrocities like the Krapex)

Dear Steve,

I want to thank you so much for jumping from "I would not use anything with the Harbor Freight name on it" to "all people of a particular color are naturally lazy, and then those people of another color are dishonest".  I imagine in your vast experience, that jump was easy to make.  Then again, perhaps your experience is only half vast.

 

[Scott Whiting]

I got asked over to toss in my 2 cents here.  First off: congratulations to those of you who picked up how to face a blade in less than 10 blades.  I have tried to teach that to many folks and some never get it.  Some things to keep in mind.  If you are only getting 50% of original life from a resharpened blade get a new sharpener, you should expect 80 - 100% as much service from a resharpened blade as from new through about the first 70% of the carbide life.  There is a hidden cost in blades by only facing rather than facing and topping.  A worn blade has a radius edge.  Most sharpeners remove the radius by taking off carbide from the face and top in proportion of the height and depth of the tooth, this gives you the most sharpenings and the longest total service life of the blade. By removing the entire radius by facing you will not take full  advantage of the amount of carbide.  Something else to watch for is to make sure that all the teeth are kept the same thickness, as you remove material from the face you also make the tooth thinner because of the relief ground into the tooth.  If all the teeth are not kept the same thickness you will get a blade where all the teeth are not working and the quality of cut will decline.  Once a tooth or teeth have been overground on the face it will be that way for life as grinding on CNC equipment assumes all the teeth are the same to start with and removes the same amount of material from each tooth.  If you screw up the tooth heights or top relief angles trying to top it yourself that can be fixed with a proper regrinding.  And finally time is money, a sharpener is an employee of your shop in a way, most times it costs less to pay a sharpener than it costs you in lost productivity to regrind it yourself.

To the gentleman with the hollow ground planer knives.  That is a function of the equipment they are ground on.  The hollow should be very shallow, I have my grinding wheel offset by about .015 which is barely noticeable across a 1/8" knife.

 

[Dave Ronyak]

If Festool put out an identical machine and it said Festool on  it, then would you use it? The Harbor Freight name has nothing to do with it....

In a word - NO.  I would not attempt to sharpen a saw blade myself.  And I would not use anything with the Harbor Freight name on it.  I have bought from Harbor Freight a number of times and been disappointed every time.  Their stuff is junk in my experience, especially anything with a motor on it.

I read a thread at another forum discussing this sharpening machine.  The advice of the professional people was to steer clear of it.  Unfortunately, I cannot locate that thread now.  Oh well.

I take my blades to a local pro sharpening shop.  Most of my blades cost close to $100, some more.  No way would I trust a Harbor Freight machine to sharpen my blades.

Dave,

I have a different view.  Most of my tools are high quality, but not all.  What I buy is dependent on many factors, including whether or not precision is needed, and how often it will be used.  Last year I needed to replace the suspension in a BMW which is used in HPDE schools (on racetracks) as well as on the highway.  I bought an HF coil spring compression kit for less than $20 which enabled me to remove the springs myself and send the dampers back to Koni for a $300 cash credit.  I'll probably never use that tool again, and will likely give it to someone.  Thus, I view such HF products as an acceptable choice for a one-time project like this one that did not require precision.  Regarding the HF blade sharpener, as Nick noted, several people on different forums have indicated it will do a decent job for at least some blade requirements.  You are blessed to have a local competent sharpening shop.  I miss my old one, and the good people who ran it.

Dave R