Alternative blades for TS75

[pteubel]

Lots of folks have been wishing for an inexpensive alternative to expensive Festool circular saw blades. And after cutting many sheets of construction ply (1 1/8" thick) and dulling my Festool blade, I was looking too.  Yea, I know...I could just use another "regular" circular saw. But I really like the TS75 and use it exclusively for any type of sheet goods (including construction ply).  Nothing available, so I developed my own solution.

I got a tremendous deal on a bunch of 16t Freud Framing blades a few months ago on Amazon (i.e. $4.18 each delivered) so I decided to try out my method on these.

#1) Drill two 3/8" holes in the blade directly opposite each other to line up with the threaded holes in my friend's metal lathe faceplate.

#2) Using 1/4" cap screws, secure the blade to the faceplate LOOSELY.

#3) Bring up the tailstock with a cone center to center the blade on the faceplate referencing off the original 5/8" center hole.

#4) Tighten up the two cap screws securing the blade tightly to the faceplate.

#5) Twist out the diamond knockout.

#6) Using a carbide tipped boring bar, enlarge the center hole to 30mm.

#7) Deburr and dismount from lathe.

#8) Mount on saw and test.

There is a difference in the cut line from the original Festool blade, but that's what replaceable splinter guards are for. The only problem I found so far is the kerf is smaller with this blade, so the riving knife binds. Haven't figured that one out yet...

 

[greg mann]

Can you put a .030 shim behind the blade?

 

[Steve Jones]

Well, my first reaction is "lots of folks???" personally I brought an expensive saw (TS55) because it works better than the alternatives, and it uses not particularly expensive blades (what about $65?) but pricier than some, then again it does the job better.

I'm missing something, you prefer to use a good, expensive saw, but want to go to a bunch of trouble to use cheap blades.

Save even more money!, get some carbon steel plates, and a really, really good file...

 

[colinw]

Sorry I agree with Steve we all bought these tools because of the way they perform (i am classing the blade as a tool because in reality it is ) why down grade the performance, and also by the time I have set up these blades and machined them i might as well gone out and bought one as it has cost me $65.00 in time and labour . If you really want to save money just use your cheap blades in a cheap saw, because i cant see the advantage to spinning a cheap blade in an expensive saw as opposed to spinning it in a cheap saw...

 

[McMark]

My opinion is that what you are doing is potentially dangerous, and could be bad on the saw.  It  would be very easy to have a unbalanced blade, which could tear up the saw, or you.

 

[Eli]

Well, I say job well done. If it's working good for you then well done. Re: the splitter thickness problem, why not make a thinner splitter. If the Festool splitter matches a Festool Blade for thickness, then therein lies your answer.

 

[Zaphod]

I applaud Peter for his efforts to fill a void in the blade offerings for the Festools TS saws.  An inexpensive blade has great utility.  E.g. laminate flooring dulls even top of the line carbide blades amazingly quick.  That super duper 20 year finish is attainable because of the aluminum oxide coating, similar abrasive to that used in sandpaper.  Senseless to use a $50 blade for that purpose.  I would eagerly purchase a few $10 "disposable" blades if available. 

To opine that an expensive saw shouldn't use inexpensive blades is preposterous.  I have a Unisaw and have a cheap Crafstman blade I swap with my Forrest WWII for use with pressure treated lumber, recycled wood, cdx ply, etc.  No need to dull or damage the WWII for such mundane tasks.  The ability to use an inexpensive blade is not an affront to the tool.

 

[Dave Ronyak]

Well, I say job well done. If it's working good for you then well done. Re: the splitter thickness problem, why not make a thinner splitter. If the Festool splitter matches a Festool Blade for thickness, then therein lies your answer.

I agree with Eli.  Buy another Festool splitter then grind it down to slightly under the thickess of the kerf of the blades you are "making."  Mark it by engraving or with a permanent marker so you know which splitter goes with which blades.  I've used modified bore blades on my Shopsmith for many years without any problems whatever.  I first did so because Shopsmith used 10" blades with an 1 1/4" arbor hole, and did not offer carbide tipped blades.  So I had them modified by a professional saw sharpening shop, who set them up by referencing off the OD (the tooth circle), not the original center bore.  The cost was not significant compared to the cost of the blades.  I still have those blades today.

Dave R.

 

[Eli]

PS-cheap does not necessarily mean bad. If you read carefully he's altering Freud blades that were a good deal. Well worth the effort IMO

 

[Daviddubya]

This modification makes some degree of sense because Peter has a friend that has a metal cutting lathe.  According to a professional sharpening shop owner, it would cost $20 to $30 per blade to have this work done by a machine shop, negating most of the savings.  If the saw were a TS55, having the work done professionally would be even less of a saving compared with buying the less expensive Festool blades.  And I'd be concerned about damaging the blade from drilling two holes and resizing the arbor hole, as well as the lack of precision in drilling the arbor hole exactly in the center of the blade.  Hmmm.

 

[greg mann]

Altering blades can be done accurately or they can be done poorly. Access to the right equipment at little added cost may make it practical for some folks. If the blade is not done correctly and is out of balance you will know real quick as the saw will vibrate. For most of us this is not practical but I don't think one should dismiss it out of hand. Someone who does flooring, for example, may want to have a dozen blades done at one time. It is no different than buying sandpaper to have on hand, except there may be another zero on the bill.

Brice is looking for custom made metric PC bushings (to use with the MFS he wants to put Imperial scales on  ;D :). "Each man is crazy in his own way."

 

[Ned]

My opinion is that what you are doing is potentially dangerous, and could be bad on the saw.  It  would be very easy to have a unbalanced blade, which could tear up the saw, or you.

It would be an improvement to have fixturing that didn't require the extra holes in the blade, but an out of balance blade should be immediately obvious and doesn't seem like a high-probability danger.

Nice work, and I envy the access to a lathe.

Ned

 

[Ned]

...I'd be concerned about ...the lack of precision in drilling the arbor hole exactly in the center of the blade.  Hmmm.

He's not drilling it, he's boring it.  Stiff single point tool.  Assuming that he's indicated it in properly--and Peter certainly sounds like he knows what he's doing--the enlarged hole should be as accurately placed as the original.

Ned

 

[greg mann]

This would be very easy with a purpose built piloted reamer. A drill press would be all you need although a vertical mill like a Bridgeport would be better. Lower the pilot into the bore to align the tool, clamp the blade down (with provisions to miss the teeth, of course), and ream the hole. Single point boring is certainly acceptable too. one technique would control size more easily (reaming) and the other would better control concentricity at the cost of slightly less size control. Take your pick.

 

[pteubel]

Let me go into a little more detail on the process.

My friend (the machinist who is also a professional finish carpenter) is very nit-picky. The two holes drilled for the mounting studs were directly in-line thru the center point and within .005 of each other in respect to the distance from the center. Drilled first with a spot drill (zero deflection), chamfered, then thru progressively larger bits to get 3/8". Oh, yea...we did the drilling on his Bridgeport mill.

Since an equal amount of metal was removed from EXACT opposite sides of the blade, balance should not affected. C'mon, we're not talking JET TURBINE speeds here where balance is infinitely critical. The reason for the holes is to securely hold the blade to the faceplate because even though light cuts are taken with the boring bar, there is a fair amount of torque applied to the blade (it's hardened and requires a carbide tool to cut it). We wanted to be SURE it would not shift nor even vibrate during the boring process. We have thought of various clamping methods but the most secure way is just bolting it. With all the variety of blade configurations out there, we couldn't index/hold from the base of a gullet.

As far as how center the new bored hole is? We checked the blade before and after. ZERO difference. Of course...why should it be different? We mounted it on the lathe referencing the existing hole and it can't move with the bolts holding it during the boring process.

More thought and effort when into the project than just "let's just use a metal hole saw and drill it out bigger".

Now let's look at the economics of this. Yes, having access to a lathe and milling machine (and a friend who knows how to use them properly) is a big factor. We have alot of fun creating/modifying a variety of tools/tooling. I bought 14 blades for the price of *ONE* Festool blade (493197 18t as a comparison....$4.18 vs $60.50) for rough work. Rough meaning cutting abrasive material (e.g. used plywood). So what if the finish of the cut isn't perfect and the edge shows saw marks....as long as it STRAIGHT. I use my TS75 for everything from cutting cabinet grade plywood to roof/wall sheathing. I've got a bunch of other circular saws (6 1/2", 7 1/4" ,8 1/4", 10" ,16") to cover pretty much any other cutting I need to do, but for sheet goods, the TS is the one I use because of it's features (guide rail, plunge safety, dust collection...yes, I even use the vac outside). It doesn't sit around for a "special" project using virgin wood.

- Pete

 

[greg mann]

Peter,

I hope you didn't get the idea that I thought you were crazy. Well maybe like a fox crazy. I do have question though. When you had it clamped on the Bridgeport and indicated in on the bore, why not just bore it there? It's all set up and ready for the cut.

I see no need for you to justify what you are doing. You are making a custom tool, period.

 

[pteubel]

Not at all, Greg.

Hmmm....didn't think of using the mill for the central boring. We'll have to give that some thought.

 

[Daviddubya]

Peter - Thanks for the additonal details.  My comments above were intended to bring up some issues, not so much for you and your friend, but for other folks that are not as fortunate as you to have the equipment and an experienced operator to do the reboring successfully.  I was thinking of myself and others that would have to improvise or use a machine shop to do the same task.  It is good that your experiment has worked out well for you.

 

[bruegf]

A while back I bought some blades from Leitz and they would alter the bore size for $5 per blade.  Probably not cost effective for cheap blades, but apparently it isn't that a big of a deal to do for a shop w/ the right equipment.

Fred

 

[Dave Ronyak]

This modification makes some degree of sense because Peter has a friend that has a metal cutting lathe.  According to a professional sharpening shop owner, it would cost $20 to $30 per blade to have this work done by a machine shop, negating most of the savings.  If the saw were a TS55, having the work done professionally would be even less of a saving compared with buying the less expensive Festool blades.  And I'd be concerned about damaging the blade from drilling two holes and resizing the arbor hole, as well as the lack of precision in drilling the arbor hole exactly in the center of the blade.  Hmmm.
/quote]

It used to cost me ~$8 per 10" blade to have the 5/8" arbor enlarged to 1.25", and the custom modified blades fit the arbor more precisely than the factory blades, but that was ~20 years or more ago, so that could be $20 today.  Take the arbor to the machine shop to get the best fit.

Dave R.