I keep tearing the end grain - Router Forums
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 12 (permalink) Old 10-08-2016, 09:42 PM Thread Starter
Registered User
 
Join Date: Mar 2013
Country: United States
First Name: Carl
Posts: 59
 
Default I keep tearing the end grain

I searched to see if this has been covered, maybe I'm not good at searching, so I apologize if I'm asking a q already answered many times.

I've been making narrow trays (4.5" wide 21" long) cut and rough sanded to final size. I then round over the edges on the router table. Near the ends it curves in making a cove, then reverses to make the outside of a circle.

I know that I'm going in the right direction, (not climb) but due to the shape of the tray, the grain is cut on part (creating a cove) in what turners call compressing the grain. Then the direction changes, and makes a circular end, so the cutters are pulling the grain apart as they cut. I get a very rough torn grain on those parts. I know many people are successful routing outer curves, but I haven't been able to get results that can be sanded smooth, as some fibers are pulled out and torn off.

I saw another post where someone cutting a circle had torn grain, and it was suggested that he climb cut on part, conventional on other part. The problem I see, is that the feed direction doesn't raise the grain, the direction the bit spins does. On one quarter of the circle, the cutter is pushing into the grain, cutting fibers that are supported by uncut fibers. Next quarter of the circle, the fibers are being pulled up away from the fibers under it, making rough, torn edge. We talk about this a lot in turning, seems to me to be a problem also with routing.

How can I get better results? It seems to me that the only way would be to have another bit spinning opposite, and change part way through the curve. Obviously, that can't be done.

Long way to ask a question, but other discussions I've seen didn't address this. Thanks for reading.

One more thing, the wood is 3/4", I'm putting a 3/8" radius top and bottom, and raising the bit slightly, making 3-4 cuts. I don't think I can be more gentle with it. I'll try to upload a picture, if so you'll see I also use a bowl bit inside, have the same problem with the inside curves.

Nope, can't attach the picture(?)
Carlswoodturning is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 10-08-2016, 09:49 PM
Forum Contributor
 
Stick486's Avatar
 
Join Date: Jan 2013
Country: United States
First Name: Stick
Posts: 25,126
 
Default

see if any thing in these PDF's help...

.
Attached Images
 
Attached Files
File Type: pdf CLIMB CUTTING.pdf (74.4 KB, 70 views)
File Type: pdf R5 TEAR OUT - How to avoid....pdf (341.1 KB, 80 views)
File Type: pdf READING GRAIN.pdf (135.0 KB, 64 views)

This would have been the week that I'd have finished chewing thru the restraints...
If only new layers hadn't been added....

Stick....
Forget the primal scream, just ROAR!!!
"SNORK Mountain Congressional Library and Taxidermy”
Stick486 is online now  
post #3 of 12 (permalink) Old 10-08-2016, 10:52 PM Thread Starter
Registered User
 
Join Date: Mar 2013
Country: United States
First Name: Carl
Posts: 59
 
Default

Thanks Stick, those articles are very good to explain climb cuts, and one shows the part of the circle where the rotation of the cutter pulls the fibers before cutting, causing some to tear. The solution given to climb cut that part doesn't change the direction of the cutter. Maybe I'm looking for a solution that doesn't exist. The species of wood I'm using (gum) may be more prone to tear than others

I not very experienced at routing, but am at turning, where we have the same problem.

I tried to upload a picture, to make the problem clearer, read the directions, but at THIS post, the paper clip is not present in the top bar, so I can't
Add the pic.


So, without a pic, I'll just say that climb cut or not, the rotation of the bit is the same, and on part of the curve the cutter still pulls the fibers away from the already cut fibers, tearing some out.



So, hope this clarifies my question without the picture.
Carlswoodturning is offline  
Sponsored Links
Advertisement
 
post #4 of 12 (permalink) Old 10-08-2016, 11:03 PM
Moderation Team
 
Cherryville Chuck's Avatar
 
Join Date: Sep 2010
Country: Canada
First Name: Charles
Posts: 14,980
 
Default

Carl when you use the advanced post option it shows which file formats are accepted. Make sure yours is one of the ones in the list. If it is and you still can't attach then pm me and we'll try to work through it.

While it's true that bit rotation does contribute, climb cutting can still help because the fiber in front of what is being cut has already been trimmed off so it can't get ripped out as easily. What may happen is that it might be the fiber in front of what is being cut or a bundle of fiber that is being affected. It's worth a try to see if that helps.

Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.
Cherryville Chuck is online now  
post #5 of 12 (permalink) Old 10-08-2016, 11:04 PM
Forum Contributor
 
Stick486's Avatar
 
Join Date: Jan 2013
Country: United States
First Name: Stick
Posts: 25,126
 
Default

for the picture..
just drag and drop it from from the file/folder it's stored in...

CCW rotating router.. Bosh makes one...

This would have been the week that I'd have finished chewing thru the restraints...
If only new layers hadn't been added....

Stick....
Forget the primal scream, just ROAR!!!
"SNORK Mountain Congressional Library and Taxidermy”
Stick486 is online now  
post #6 of 12 (permalink) Old 10-09-2016, 08:15 AM Thread Starter
Registered User
 
Join Date: Mar 2013
Country: United States
First Name: Carl
Posts: 59
 
Default

Ok, the advanced option brings up that paper clip, will add the pic that way.

As for the drag and drop, I'm using an iPad, can't do it as far as I know, Apple won't let me open 2 windows at once. Copy and paste adds the pic extremely large, and usually I can't get the paste option on this screen.

Back to woodworking!

I can see that climb cut can help, but due to the change from inside to outside curves, I can't use the fence. (I've been using a top bearing bit) Since I take very small amounts off each pass, maybe I can keep it from flying off, I'll practice with some scrap.

I suppose a new bit might help also.
Attached Thumbnails
Click image for larger version

Name:	image.jpg
Views:	103
Size:	749.5 KB
ID:	236906  

Carlswoodturning is offline  
post #7 of 12 (permalink) Old 10-09-2016, 11:45 AM
Forum Contributor
 
MEBCWD's Avatar
 
Join Date: Jan 2012
Country: United States
First Name: Mike
Posts: 3,020
 
Default

Here is a video that explains what is happening and the bit to use to solve the problem. This is not the only bit with top and bottom bearings, check around and you will find several and some spiral and even compression bits.


Mike
Your BRAIN Is The Most Important Power Tool In Your Shop. Turn It On Before You Turn On Any Other Power Tool.
A Disability Is Only A Disability If You Let It Be One
MEBCWD is online now  
post #8 of 12 (permalink) Old 10-09-2016, 11:47 AM
Registered User
 
Join Date: Mar 2014
Country: United States
First Name: Tom
Posts: 1,424
 
Default

The parts for the turtles I've been making have the same problem in that the grain direction "changes" as you go around the part. I compensate by varying the direction of feed based on the grain direction, sometimes routing in the "normal" direction and then switching to climb cutting. I get better results by cutting the areas where I use climb cutting first and then filling in between them cutting in the normal direction. I'm only cutting a 1/4" roundover, for a larger radius I would probably cut in two passes but following the same procedure.
Attached Thumbnails
Click image for larger version

Name:	IMG_4335.JPG
Views:	90
Size:	584.8 KB
ID:	236922  

Click image for larger version

Name:	IMG_4338.JPG
Views:	82
Size:	615.5 KB
ID:	236930  

tomp913 is offline  
post #9 of 12 (permalink) Old 10-09-2016, 01:17 PM
Registered User
 
Join Date: Jun 2011
Country: United States
First Name: Barry
Posts: 531
 
Default

Carl, I have several of the bits that Mike mentioned, 2 Katana and one Whiteside. Different lengths and diameters. I use them with templates as shown in the video and I rarely get tearout. When I do it's because I went too far against the grain before stopping. However, if you're only routing one edge then tom's suggestion is the way to go. When climb cutting be careful that you don't lose control of the work piece.
Barry747 is offline  
post #10 of 12 (permalink) Old 10-10-2016, 11:02 AM
Registered User
 
Join Date: Sep 2016
Country: United States
First Name: Scott
Posts: 100
 
Default

you could try and epoxy consolidating the entire piece with a very low viscosity epoxy like Smiths Epoxy. This won't leave a layer of finish on the surface but will strengthen the fibers. I've also had luck with CA glue. I like Parson brand which is designed for this purpose. Used for punky wood before carving and or turning.
hope this helps.
scottgrove is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Router Forums 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











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Newbie end grain question steamingbill Woodturning and Lathes 3 06-03-2013 09:28 PM
Staining end grain rstermer The Finishing Touch 11 02-21-2009 09:22 AM
Routing end grain Pop_pop1 Table-mounted Routing 8 09-22-2004 01:24 PM

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 On
Refbacks are On

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