Riving Knifes on Track Saw

[Steven Owen]

Do you believe Riving Knives are necessary on track saws? 

So many manufacturers don’t have riving knives like the Makita, Bosch, Mafell, and Triton.  Dewalt and Festool are some of the few companies that include riving knives on their track saw.

I’m pretty much trying to decide between getting the Cordless Makita or the TS75 Track Saw.  The thought Makita not having a riving knife has me leaning harder towards getting the TS 75. 

What’s your thoughts?  Does the lack of a riving knife on the Makita a huge issue for hardwood cuts like hardwood table tops?

 

[Svar]

For me riving knife was an important factor. Larger Mafell saws do have them. It's a good feature if you mount your saw under the table.

 

[peter halle]

Personally I am happy to have one.  We have read here about users who have cut sheet goods and experienced the kerfs closing.  I especially am glad when ripping lumber that always has the possibility or releasing internal stresses.

Is it necessary?  Probably not.  But if available versus unavailable on the same model saw I would go riving knife every day of the week - no matter what brand the saw is.

Peter

 

[JFelchlin]

Peter:
I’m absolutely with you - 110%. No riving knife. No saw.
15+ years ago - When I first got into woodworking - A friend let me use his table saw.
It had no riving knife or anti-kickback pawls.
Worse... I was standing directly behind/in line with the blade - When a 1x8 I was ripping -
Kicked back on me - Directly into my gut - Breaking two ribs. [sad]
Healed three months later - I took a woodworking class at my local Woodcraft store -
Learning the right way to use a table saw and other woodworking power tools.
Shortly thereafter, I bought my Festool TS 75 EQ (WITH RIVING KNIFE), MFT1080 table and Guide Rails.
A few years ago - Much more experienced - I did buy a Bosch 4100-09 Worksite Table Saw - But only after making sure that it came with a riving knife and anti-kickback pawls for protection.
Even after all these years of woodworking -
I wouldn’t own a saw without this basic equipment!
Do enough woodworking long enough - And it’s not “IF” - It’s “WHEN”. Avoid the pain. [wink]
P.S.
Steven: Get the Festool TS 75. It’s a great saw![smile]

 

[Steven Owen]

Personally I am happy to have one.  We have read here about users who have cut sheet goods and experienced the kerfs closing.  I especially am glad when ripping lumber that always has the possibility or releasing internal stresses.

Is it necessary?  Probably not.  But if available versus unavailable on the same model saw I would go riving knife every day of the week - no matter what brand the saw is.

Peter

I agree.  I’ve never understood why Makita and the other Track Saw Manufactures are neglecting to put riving knives on their tools.  It’s not really a cost factor when compared with a serious injury caused by an accident of any kind. 

Makita made to add a clip to keep the Saw from tipping when cutting bevels.  I’ve always been baffled by Makita’s decision to not put a riving knife on their Track Saw.
 

 

[ScotF]

Personally I am happy to have one.  We have read here about users who have cut sheet goods and experienced the kerfs closing.  I especially am glad when ripping lumber that always has the possibility or releasing internal stresses.

Is it necessary?  Probably not.  But if available versus unavailable on the same model saw I would go riving knife every day of the week - no matter what brand the saw is.

Peter

I agree.  I’ve never understood why Makita and the other Track Saw Manufactures are neglecting to put riving knives on their tools.  It’s not really a cost factor when compared with a serious injury caused by an accident of any kind. 

Makita made to add a clip to keep the Saw from tipping when cutting bevels.  I’ve always been baffled by Makita’s decision to not put a riving knife on their Track Saw.

I am not sure that a riving knife is critical for a track saw cutting mostly sheet goods. Solid wood with more tension is a different matter. By design track saws are inherently safe as a kickback on the machine and the blade immediately goes into the cover. I think that the Mafell cuts the power if the blade stops. With that said, I do prefer having a riving knife for the peace of mind. At the end of the day I put trust in the engineers if a saw is designed with or without a riving knife.

 

[semenza]

Yes, I definitely want the riving knife for ripping solid wood. Watch the kerf behind the saw as you push it down the track and many times you can see it opening or closing. And often when it is closing quite a bit you will hear the saw work a little harder which probably means the knife is actually doing something in keeping the kerf open enough to keep cutting.

Not a big deal on sheet goods but I have had some that had a kerf tighten or the sheet is warped and pops up behind the blade as you cut. Certainly doesn't hurt to have it.

Seth

 

[Svar]

I think that the Mafell cuts the power if the blade stops.

At that time it's too late.

 

[Steven Owen]

Yes, I definitely want the riving knife for ripping solid wood. Watch the kerf behind the saw as you push it down the track and many times you can see it opening or closing. And often when it is closing quite a bit you will hear the saw work a little harder which probably means the knife is actually doing something in keeping the kerf open enough to keep cutting.

Not a big deal on sheet goods but I have had some that had a kerf tighten or the sheet is warped and pops up behind the blade as you cut. Certainly doesn't hurt to have it.

Seth

It’s why I’m inclined to get the TS 75.  I need a saw that can handle both hardwoods and plywood cuts for the interim.  I don’t have the budget to buy two track saws.  I don’t want to chance a kickback in a pricey hardwood cut. 

 

[Stone Message]

The riving knife on the TS 55 was an important factor when I bought mine.

When using my old circular saws I had experienced the blades being nipped. This often happened with longer cuts and either slightly distorted (ie cheap) plywood or when my trestles were uneven. On one occasion the saw completely exited the cut and I clipped my aluminium straight edge with the spinning blade.

The other factor is that should you decide to put a TS in a CMS unit then the built in riving knife will allow you to do rebate work (without the blade guard which has the additional riving knife attached). For me this is a major plus for the CMS-TS.

Peter

PLEASE NOTE:
Festool do not recommend the use of the CMS-TS without the blade guard. Anyone removing it to do any form of cut does so at their own risk.

 

[demographic]

If you'd seen the massive heap of manky warped plywood I sometimes have to deal with you'd want a riving knife.

 

[WastedP]

Riving knives on everything.

If you're looking at the Makita tracksaw vs the TS75, the Festool has a larger cut capacity.  If there was a cordless tracksaw that could bag sawdust and cut 3", I'd buy it.

 

[Steven Owen]

The riving knife on the TS 55 was an important factor when I bought mine.

When using my old circular saws I had experienced the blades being nipped. This often happened with longer cuts and either slightly distorted (ie cheap) plywood or when my trestles were uneven. On one occasion the saw completely exited the cut and I clipped my aluminium straight edge with the spinning blade.

The other factor is that should you decide to put a TS in a CMS unit then the built in riving knife will allow you to do rebate work (without the blade guard which has the additional riving knife attached). For me this is a major plus for the CMS-TS.

Peter

PLEASE NOTE:
Festool do not recommend the use of the CMS-TS without the blade guard. Anyone removing it to do any form of cut does so at their own risk.

I agree Peter.  In this modern day of safety awareness and increased focus on workplace safety there should be a mandatory regulations in place for each county making it a standard requirement for all track and circular saws to have riving knives. 

I don’t think any manufacture should be allowed to make a Track Saw that without a standard riving knife.

 

[RussellS]

I am FOR riving knives on saws.  Except jigsaws and hand saws.  I've used my Festool 55 on particleboard countertops and gotten burning on the sides due to it closing up behind the blade.  I'm glad the riving knife was there to keep it from closing entirely around the blade and causing serious problems.  I have a riving knife on my table saw.  It stays on.

 

[Sanderxpander]

The Mafell MT55 doesn't need one according to Mafell as it was designed specifically to be safe withour one. Srr this  thread:http://festoolownersgroup.com/other-tools-accessories/who-needs-a-riving-knife/

I don't know if this goes for the Makita as well, perhaps they're the ones to ask.

 

[Steven Owen]

The Mafell MT55 doesn't need one according to Mafell as it was designed specifically to be safe withour one. Srr this  thread:http://festoolownersgroup.com/other-tools-accessories/who-needs-a-riving-knife/

I don't know if this goes for the Makita as well, perhaps they're the ones to ask.

I think Mafell is assuming their Saw will mostly be used for sheet goods.  I think Festool has the right idea with retaining the riving knife, especially for hardwood cutting applications.

Makita’s Saw locks into it’s track.  That may be why Makita has decided to omit the riving knife.  With the depth of cut on the TS 75, it would be extremely unwise to not have a riving knife on a Saw with the 75’s cutting capacity. 

 

[Sanderxpander]

If you read the official response from Mafell posted in that thread it isn't as simple as that. They specifically tested all the other safety features necessary to warrant omitting a riving knife.
EDIT:

Actually I'll repost it, then maybe people will feel like reading it:

PRESS RELEASE
Safer sawing without a riving knife

MAFELL MT 55 cc plunge-cut saw with kick-back protection

In its new MT 55 cc plunge-cut saw, MAFELL has combined the benefits of enhanced active safety, improved handling and enhanced cut quality – without a riving knife. According to the manufacturer, active kick-back protection averts the danger of recoil when the blade enters the work more effectively than a riving knife. In addition, design measures introduced alongside standard EN 60745-2-5, which entered force in 2007, have increased the passive safety of saws that dispense with a riving knife.

Especially when entering the workpiece, the blade of conventional plunge-cut saws can easily jam and thus cause a kick-back. The MAFELL MT 55 cc plunge-cut saw significantly reduces the likelihood of this effect occurring. Thanks to the CUprex Compact motor driving the sawblade at a maximum of 6,200 rpm, the cutting speed is 20 per cent higher than usual. The teeth of the carbide-tipped sawblade thus remove less stock per revolution, which appreciably reduces the risk of jamming.

The probability of a kick-back arising from sawblade jamming is much lower while sawing is in progress as well. The high speed enables the blade to cut itself free more effectively. Additional safety is afforded by the automatic isolation of the power supply to the motor if the blade jams.

"The active kick-back protection provided by the high speed and automatic power supply interruption offers greater safety than a riving knife, which does not protect against the kick-back effect when the blade enters the work and can be a nuisance for the tradesman," comments Ralf Kohler, head of sales and marketing at MAFELL. Josef Riederer, a tradesman of Unterneuhausen, vindicates the manager's claim, "I feel safe when working with the MT 55 cc."

The passive safety of the MAFELL MT 55 cc plunge-cut saw is also enhanced by the strict provisions of EN 60745-2-5 for saws without a riving knife. In the event of a kick-back, the standard requires that the sawblade fully retracts inside its housing within just 0.3 seconds. In compliance with the standard's provisions, MAFELL tested this safety feature more than 50,000 times.

Dispensing with a riving knife makes the saw much easier to use. When changing the sawblade, for example, it is no longer necessary to change the riving knife according to the blade thickness and adjust it to suit the blade diameter. This not only accelerates the blade changing operation, but also reduces the workload when working with a variety of materials. Tradesmen are also delighted that the absence of a riving knife protects sensitive surfaces against the risk of scratch marks.
Media contacts:

Volker Simon​Ralf Kohler
Tel.: ​+49 711 248922-169​Tel.: ​+49 7423 812-135
Fax: ​+49 711 342185-32​Fax: ​+49 7423 812-218
E-mail: ​volker.simon@lmpr.de​E-mail: ​ralf.kohler@mafell.de

 

[Svar]

I'm sure Mafell tested their saws and it's all arm waving on my part, but there are problems with their claims above:
1) Blade speed is variable, so the user may have it set lower than 6200 rpm, which Mafell deems "safe"
2) When the blade jams it's to late to cut off power. Kick back occurs while the blade is moving. Kick back may not be associated with any significant change in blade speed at all.
3) Spring loaded riving knife is not "nuisance for the tradesman". I does not interfere with cutting in any way.
4) "absence of a riving knife protects sensitive surfaces against the risk of scratch marks" How? The knife is inside the kerf!

 

[Michael Kellough]

I started with the ATF 55. That knife is not spring loaded so it does have to be removed for plunge pocket cuts. The ability to make those cuts accurately is the best (most unique) feature of a plunge cut track saws.

The knife has been off that saw for over a decade. Never been a problem but I have preemptively added a shim to the kerf shortly after getting going to make sure a tense board won’t bind the blade. Another great thing about track saws is the ability to stop and re-start a cut without penalty.

I do wish Festool track saw rpms were higher.

 

[Laminator]

I removed the (non retracting) riving knife from my atf55 many years ago and never missed it.  I replaced the atf55 with the mt55 a few years back and have never noticed any problem with it not having a riving knife.
  My ts55 riving knife has never caused any problems and works as it was designed.
  If the atf55 knife had have been spring loaded there would have been no need to remove it.