LumberJocks

TS kerf too thin for riving knife?

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by BadWolfBrewing posted 10-31-2017 01:56 PM 863 views 0 times favorited 10 replies Add to Favorites Watch
View BadWolfBrewing's profile

BadWolfBrewing

8 posts in 1321 days


10-31-2017 01:56 PM

Topic tags/keywords: table saw kerf riving knife question

Greetings all,

I have a sawstop PCS, and purchased a Freud Premium Fusion thin kerf combo blade, with a kerf of 0.091”. The sawstop riving knife is 2.3 mm, or 0.0906”. The manual says to not use a blade thinner than 0.0925”, but I didn’t see that in time.

For cross cuts, all is well and the cut is beautiful. For rip cuts, especially longer rip cuts, the board wants to pull away from the fence after the blade. This results in a ton of drag/friction and a burnt cut with a lot of blade marks. There have been cuts where I couldn’t push it through and had to turn off the saw.

Is this caused by the riving knife being too thick? I never had this issue with the stock blade from sawstop. That blade isn’t great, it burnt 3/4” oak and poplar on rip cuts. Or, maybe the fence isn’t perfectly aligned to the blade and that problem is exacerbated by the thin blade?

I ordered a 2.0mm riving knife which might help a little bit. I thought I’d post the question on here to see if the experts had some experience in the matter. Mostly I want to make sure that it’s the riving knife being too thin that is messing up my cuts and not a problem with the saw calibration.

Thanks in advance,


10 replies so far

View CharlesNeil's profile

CharlesNeil

2410 posts in 3893 days


#1 posted 10-31-2017 01:59 PM

Riving knife is too thick , SS makes one for thin kerf , i believe

View BadWolfBrewing's profile

BadWolfBrewing

8 posts in 1321 days


#2 posted 10-31-2017 02:03 PM

They do. It isn’t listed as compatible with the PCS, but I’ve read that others have used it without problem so I’ve ordered it. Only 15 bucks, though the 12 bucks shipping seemed excessive…

So a thick riving knife can cause the wood to pull from the fence? That is my main concern. I screwed up some important cuts that will cause a lot of rework, so I want to make sure there isn’t a bigger issue and I’m new to ‘precision’ wood working.


Riving knife is too thick , SS makes one for thin kerf , i believe

- CharlesNeil


View Dustin's profile

Dustin

529 posts in 763 days


#3 posted 10-31-2017 02:14 PM

I have that same blade and the same problem on my Delta 36-725 (the Freud Industrial rip blade LU87R010, though thin kerf, is thicker and poses no problems). I tried to use my belt sander to thin it down a bit, but the results were iffy. As I now only use that blade for cross cuts, it’s a moot point for me.

To answer your question, if you think of the riving knife and “Pinching” the wood where it contacts, this is creating a fulcrum/pivot-point, which may try to push the trailing end of the piece away from the fence. As it is, buying a dedicated rip blade was a great improvement to my cuts in burn prone hardwoods like cherry (especially since my saw is underpowered: 8/4 material posed no challenge), so if the thin riving knife isn’t to your liking, this may be an alternative approach. They’re pretty affordable, and I’ve found the time it take me to change blades is nicely counterbalanced by the time I save via smoother operation and not having to spend as much time cleaning up the edges.

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

View MrRon's profile

MrRon

4793 posts in 3266 days


#4 posted 10-31-2017 04:33 PM

A good reason not to use a riving knife.

View BadWolfBrewing's profile

BadWolfBrewing

8 posts in 1321 days


#5 posted 10-31-2017 05:33 PM

I’ve only heard one person recommend not using a riving knife and that is my grandfather. He does have all of his fingers though.

Is this a common opinion? All I’ve read is the benefits of the riving knife. Is there another alternative to reduce the chance of kickback?


A good reason not to use a riving knife.

- MrRon


View Dustin's profile

Dustin

529 posts in 763 days


#6 posted 10-31-2017 05:43 PM



I ve only heard one person recommend not using a riving knife and that is my grandfather. He does have all of his fingers though.

Is this a common opinion? All I ve read is the benefits of the riving knife. Is there another alternative to reduce the chance of kickback?

A good reason not to use a riving knife.

- MrRon

- BadWolfBrewing

As far as alternatives go, there are splitters, but they don’t raise/lower with the cut. A lot of blade guards now have anti-kickback pawls as well.

Keep in mind that like other safety devices, when misused (improper setup, used out of spec, etc) a riving knife can cause more problems than it solves. However, a properly set up riving knife is a good step toward safer operation. I’ve never had a full force kickback, but I’ve felt cuts binding enough on thicker pieces that I only take mine out now when cross-cutting with a sled.

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

View Sarit's profile

Sarit

549 posts in 3162 days


#7 posted 10-31-2017 05:52 PM

I encountered the same problem, figured out a solution, and blogged about it here:

http://lumberjocks.com/Sarit/blog/114025

You can make it work as the kerf is actually bigger than the knife, however there’s practically no tolerance for the blade being slightly tilted in relation to the knife. Trying aligning it with the blade all the way up, then see if its still aligned with only 3/4” of the blade exposed above the table.

View pintodeluxe's profile

pintodeluxe

5702 posts in 2836 days


#8 posted 10-31-2017 05:59 PM

You will be fine once you switch to the TK riving knife.
Here is a writeup I did on the standard vs. thin kerf riving knives from Sawstop.
http://lumberjocks.com/pintodeluxe/blog/100778

All the best.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Redoak49's profile

Redoak49

3278 posts in 2011 days


#9 posted 10-31-2017 06:01 PM

I find the Freud Premier Fusion blade to be a bit difficult at times. It has very tight side clearance and will burn on rip cuts. If your board is not tracking properly you can get burning. Same issue if the fence not perfectly parallel to blade. I like the blade but not as much for ripping.

I have read other reports of people having burning issues.

View BadWolfBrewing's profile

BadWolfBrewing

8 posts in 1321 days


#10 posted 10-31-2017 06:30 PM

Perfect writeup, I didn’t find that from a brief google-about.

New knife shipped, should be here soon.

Interesting note about the blade burning a little. I guess they couldn’t make the blade body any thinner and have it be structurally sound. I do have the Freud industrial glue-line rip blade as well, but didn’t want to pull it out for plywood. Perhaps I should get a dedicated plywood blade as well.

I’ll test out the knife alignment vs the blade alignment. Looks like an easy enough fix if that is the issue, along with the thinner knife.

On a related note, I’m amazed how easy it is to change blades in the sawstop. I had a bosch 4100 that had an arbor lock, but it was more work than it saved. Having two wrenches and plenty of room to get them both in there works great.

Thanks for all the help, I got the info I need. This is a great resource


You will be fine once you switch to the TK riving knife.
Here is a writeup I did on the standard vs. thin kerf riving knives from Sawstop.
http://lumberjocks.com/pintodeluxe/blog/100778

All the best.

- pintodeluxe


Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com