Help with long rip cuts on table saw - Woodworking Talk - Woodworkers Forum
 3Likes
  • 1 Post By gmercer_48083
  • 1 Post By DrRobert
  • 1 Post By shoot summ
 
Thread Tools Display Modes
post #1 of 18 Old 06-28-2020, 02:07 AM Thread Starter
Junior Member
 
Join Date: Jun 2020
Posts: 2
View drewhill33's Photo Album My Photos
Unhappy Help with long rip cuts on table saw

Hi! I have been troubleshooting my Grizzly table saw and I am stumped.

I am ripping 8 foot pieces of oak and everything is going great until the end of the cut. Once the front of the blade gets through the end of the piece of wood and I have to push the end of the wood entirely past the back of the saw, I have a problem. The wood is pushing into the saw blade and the last 4-5 inches of the rip cut are not 90 degrees. When I get the wood past the saw I can see that the wood is visibly pushing the riving knife to the left of the blade (my fence is on the right of the blade). If I stop the saw as soon as the front of the blade passes through the end of the wood and let the saw come to a stop I end up with an acceptable cut. The pieces I am ripping are joining up nicely.

I have watched numerous table saw alignment videos trying to figure out what is wrong. One thing I discovered using a dial gauge and a jig for the miter tracks is that my fence has a slight deflection in the middle of about 5/1000 of an inch. I can align the front and back of the fence to within 1/1000 of an inch however the middle however the middle would be 5/1000 further away from the miter slot. I have tried adjusting the fence so it angles away from the blade by 5/1000 of an inch but that does not help. Also, the last 4-5 inches of the wood (when I push all the way through) is visibly at an angle so the issue is way more than 5/1000 of an inch.

I don't notice this issue when I rip shorter boards so I assume that my misalignment is building up over the length of the long boards. I am using an outfeed roller stand and I have a 48" flat aluminum bar and as far as I can tell everything is perfectly level with the table.

Thanks for taking the time to read this and thanks for any suggestions.
drewhill33 is offline  
Sponsored Links
Advertisement
 
post #2 of 18 Old 06-28-2020, 08:36 AM
Senior Member
 
TomCT2's Avatar
 
Join Date: May 2014
Location: Central PA
Posts: 1,387
View TomCT2's Photo Album My Photos
check the alignment of the riving knife. it has three "degrees of freedom"


1. parallel to blade & miter slot
2. vertical to table
3. centered in kerf



then there's "narrower/thinner" than the kerf - which is a known problem/conflict with most manufacturers and "thin kerf blades"
TomCT2 is offline  
post #3 of 18 Old 06-28-2020, 10:51 AM
Senior Member
 
Join Date: Jul 2008
Location: Florida Panhandle
Posts: 12,371
View GeorgeC's Photo Album My Photos
I do not have a riving knife on my saw. Therefore, I am able to use a feather board on the outfeed side if the blade when I am cutting a long board. This keeps the board gently pressed against the fence all the way through the cut. Do not know if this would work with your saw configuration.


George.
GeorgeC is offline  
Sponsored Links
Advertisement
 
post #4 of 18 Old 06-28-2020, 11:13 AM
Senior Member
 
Join Date: Apr 2016
Location: Troy Michigan USA
Posts: 1,217
View gmercer_48083's Photo Album My Photos
I had that problem ripping long boards. turned out it was being deflected slightly by the roller stand. I now use a permanently attached (hinged) outfeed table, so when I move my table saw in my small shop... it stays perfectly aligned with the table. When necessary... I can fold it down or up. Being that the outfeed table references off of the table saw and not a possible un even floor, made the drifting go away.
cynrich likes this.

Gary

Woodworking is like wetting myself....Only I know that warm feeling!
gmercer_48083 is offline  
post #5 of 18 Old 06-28-2020, 11:17 AM
Senior Member
 
Join Date: Apr 2016
Location: Troy Michigan USA
Posts: 1,217
View gmercer_48083's Photo Album My Photos
Quote:
Originally Posted by GeorgeC View Post
I do not have a riving knife on my saw. Therefore, I am able to use a feather board on the outfeed side if the blade when I am cutting a long board. This keeps the board gently pressed against the fence all the way through the cut. Do not know if this would work with your saw configuration.


George.
Using a feather board on the outfeed end of the table saw would pinch the off cut into the blade I would think. please explain.

Gary

Woodworking is like wetting myself....Only I know that warm feeling!
gmercer_48083 is offline  
post #6 of 18 Old 06-28-2020, 11:27 AM
CharleyL
 
Join Date: Jan 2019
Location: Central North Carolina
Posts: 281
View CharleyL's Photo Album My Photos
A longer fence or fence extension and an out feed table will take care of this problem. You need the fence extension to keep the board feeding straight and with your shorter fence it is no longer being guided as you reach the end of the cut. A long straight board that is attached to the face of your existing fence will work. DO NOT use a feather board behind the blade. It will close the kerf and result in a possible kick-back. Make certain that your fence is truly parallel with the blade and miter slot of your table saw too, not just close. It needs to be adjusted to be about as parallel as you can get it. A few thousandths wider at the out feed end is sometimes better. Use machinists measuring tools like a dial or digital caliper for this kind of measurement. A ruler or scale isn't good enough.

Charley
CharleyL is offline  
post #7 of 18 Old 06-28-2020, 11:50 AM
Junior Member
 
Join Date: Feb 2019
Posts: 1
View Rheal's Photo Album My Photos
If it's help you
Attached Images
 
Rheal is offline  
post #8 of 18 Old 06-28-2020, 12:39 PM
Senior Member
 
Join Date: Jul 2008
Location: Florida Panhandle
Posts: 12,371
View GeorgeC's Photo Album My Photos
Quote:
Originally Posted by CharleyL View Post
A longer fence or fence extension and an out feed table will take care of this problem. You need the fence extension to keep the board feeding straight and with your shorter fence it is no longer being guided as you reach the end of the cut. A long straight board that is attached to the face of your existing fence will work. DO NOT use a feather board behind the blade. It will close the kerf and result in a possible kick-back. Make certain that your fence is truly parallel with the blade and miter slot of your table saw too, not just close. It needs to be adjusted to be about as parallel as you can get it. A few thousandths wider at the out feed end is sometimes better. Use machinists measuring tools like a dial or digital caliper for this kind of measurement. A ruler or scale isn't good enough.

Charley

When you use a feather board behind the blade you do not set it with any pressure on the wood. It is set so that it just touches the outfeed wood and keeps it from drifting to the left. You could also clamp a piece of wood on the saw table to achieve the same result. A feather board is just easier to mount.


George
GeorgeC is offline  
post #9 of 18 Old 06-28-2020, 01:36 PM Thread Starter
Junior Member
 
Join Date: Jun 2020
Posts: 2
View drewhill33's Photo Album My Photos
Thanks for all of the suggestion! Considering all of the times I have spent checking alignment the longer fence makes sense and is the next thing I will try. I really spent time shimming my roller stand to get it level (thought it is 1/8" lower than the table) but I will check that again.
drewhill33 is offline  
post #10 of 18 Old 06-28-2020, 09:17 PM
Member
 
Join Date: Apr 2019
Location: Near Richmond VA
Posts: 31
View RonBenson's Photo Album My Photos
Is your roller stand a solid tube that rotates. (like a rolling pin), or is it a set of free rolling ball bearings? If it's the first, the roller must be perpendicular to the board you are cutting. If it's slightly out, it will try to move your board to one side or the other. I learned this the hard way...
RonBenson is offline  
post #11 of 18 Old 06-29-2020, 12:01 AM
Senior Member
 
Join Date: Apr 2018
Location: Southwest Michigan
Posts: 257
View Echo415's Photo Album My Photos
Quote:
Originally Posted by drewhill33 View Post
I have watched numerous table saw alignment videos trying to figure out what is wrong. One thing I discovered using a dial gauge and a jig for the miter tracks is that my fence has a slight deflection in the middle of about 5/1000 of an inch. I can align the front and back of the fence to within 1/1000 of an inch however the middle however the middle would be 5/1000 further away from the miter slot. I have tried adjusting the fence so it angles away from the blade by 5/1000 of an inch but that does not help. Also, the last 4-5 inches of the wood (when I push all the way through) is visibly at an angle so the issue is way more than 5/1000 of an inch.
Don't get caught up thinking like a machinist. Table saws aren't manufactured to be that precise. Getting concerned over a few thousandths is pointless when dealing with woodworking. Align your blade parallel to the miter tracks, align the fence so it deflects slightly away from the blade on the outfeed side of the cut(otherwise your work gets pinched between the blade and the fence) and you should be fine with saw setup. The rest is like others have said...likely that your roller guide is the culprit.
Echo415 is offline  
post #12 of 18 Old 06-29-2020, 01:25 AM
mike44
 
Join Date: May 2020
Location: mays landing nj.
Posts: 95
View kwoodhands's Photo Album My Photos
Does your fence have a plastic , nylon or whatever face on the steel tube? Have you tried to shim the face til it is acceptable ? My saw is an older version of yours, no riving knife and tilts right. I removed the nylon face and replaced it with "Fin board". This is a 13 ply birch plywood . The nylon face was not flat across the length. I did not know if it could be jointed flat like wood. I had the plywood on hand. I checked the fence after replacing the face, no appreciable deflection was found. Try Baltic birch plywood and shim if necessary. .5000 is a lot, printer paper is .4000
and you can feel the difference .
One thing I do not understand, you say the last 4/5" is not square. Do you mean that the end of the cut is not straight ? I have never used a saw with a riving knife, actually haven't even seen one. I used to mount a hardwood wedge on the insert to keep the kerf from closing up on rip cuts. I imagine a riving knife does this too.
I generally use a power feeder when ripping so the blade guard and splitter have been removed. The wedge does a nice job of keeping the kerf open.
mike
kwoodhands is offline  
post #13 of 18 Old 06-29-2020, 02:35 PM
Senior Member
 
Join Date: Apr 2015
Location: NE FL
Posts: 602
View DrRobert's Photo Album My Photos
I strongly suggest you abandon the roller stand! They are not appropriate as an outfeed support because unless perfectly 90 to the blade kerf or a slight skew will track the board one way or another.

A riving knife or spiltter are an absolute must for me this is not debatable.

If you want to use a roller stand, use an omnidirectional like the one mentioned by RonBenson.
subroc likes this.

Robert
DrRobert is offline  
post #14 of 18 Old 07-02-2020, 07:10 PM
Senior Member
 
GoIrish's Avatar
 
Join Date: Jan 2012
Location: Houston
Posts: 464
View GoIrish's Photo Album My Photos
I have had the same issue. It was my roller stands. Too hard to get the aligned. I donated mine.
GoIrish is offline  
post #15 of 18 Old 07-02-2020, 07:29 PM
where's my table saw?
 
woodnthings's Avatar
 
Join Date: Jan 2009
Location: SE, Michigan
Posts: 27,287
View woodnthings's Photo Album My Photos
I hate roller stands!

Quote:
Originally Posted by GoIrish View Post
I have had the same issue. It was my roller stands. Too hard to get the aligned. I donated mine.

I only use mine far after the outfeed table to just catch the pieces that are already past the rear of the blade, so no influence on the cut being made. A smooth, solid outfeed surface is what I have found to be the best. Mine extends about 48" from the rear of the table, so plenty of support for most cuts and for long rips, the roller stand comes out.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
woodnthings is offline  
post #16 of 18 Old 07-02-2020, 09:14 PM
Member
 
Join Date: Aug 2013
Posts: 36
View Biggrbird2013's Photo Album My Photos
I agree with RonBenson. If the roller pin variety is not perfectly perpendicular to the blade the rollers will pull the wood toward/away from the blade, especially long boards, even if the rollers are the same height as the table. Notice you mentioned you did not have problems on shorter boards which probably do not touch the roller stand.
Biggrbird2013 is offline  
post #17 of 18 Old 07-02-2020, 10:05 PM
Senior Member
 
Join Date: Nov 2019
Posts: 148
View B Coll's Photo Album My Photos
How is the sharpness,type, and quality of your blade? What blade height are you using? You should not have to work that hard. The length of the fence should not matter. Your blade should run dead parallel to the miter slot, I like my fence open about 1-2/1000 on the outfeed end. Have no scientific evidence it makes a difference, just the way I was taught. Blades can start to deflect when they get hot, which would be the end of the cut. I would make sure you have a good, stable, sharp blade. U have always used Forrest Mfg. blades, the Woodworker II is a good choice. They are pricey but you will have it for ten years. I would also try, if you have not already, raising the blade well above the stock.
B Coll is offline  
post #18 of 18 Old 07-03-2020, 07:20 AM
Smart and Cool
 
Join Date: Feb 2014
Location: Oklahoma
Posts: 1,886
View shoot summ's Photo Album My Photos
For long rips I tend to go half way, lift the piece off, flip it around and over, then restart from the other end. That way I end half way and don't have to deal with an 8' piece hanging off the back of my saw.
woodnthings likes this.
shoot summ is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Woodworking Talk - Woodworkers Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome