Rounded corners on metal latche - Woodworking Talk - Woodworkers Forum
 
Thread Tools Display Modes
post #1 of 8 Old 06-25-2011, 04:27 PM Thread Starter
Junior Member
 
Join Date: Jun 2011
Posts: 3
View Sivy's Photo Album My Photos
Rounded corners on metal latche

Hello, Im from Poland, so my english is not good, but you propably understand this :-)
I have big problem with woodturning and anybody can't help me.

I want to make rounded corners in wood. I have metal lathe. First I take soft wood and "made in china" knife (this yellow on photo) for hand mill machine. It's not have straight blades, so I can't perfectly position it in lathe center axis. But as you see, it's possible to make something with it.

Next I take merbau wood (i know, it's very hard) and bought CMT knife for rounded shapes. The top of the blade is perfectly in lathe center axis. I set lathe to 700rpm and start cutting. It's make high sound and wobbling. It's look as it won't cutting. The wood is getting hot if i tried to cut it longer. Knife blade is very sharp and easly cut paper.

What Im doing wrong?
Attached Thumbnails
Click image for larger version

Name:	tocz.jpg
Views:	281
Size:	96.7 KB
ID:	25897  

Click image for larger version

Name:	drew1.jpg
Views:	159
Size:	83.6 KB
ID:	25898  

Click image for larger version

Name:	drew2.jpg
Views:	403
Size:	52.3 KB
ID:	25899  

Click image for larger version

Name:	drew3.jpg
Views:	184
Size:	78.4 KB
ID:	25900  

Sivy is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 06-25-2011, 04:48 PM
Old School
 
cabinetman's Avatar
 
Join Date: Jul 2007
Location: So. Florida
Posts: 24,027
View cabinetman's Photo Album My Photos


The bit (yellow coated) is a router bit. If you preshaped the wood to a circle, using the bit in a router will edge the profile. The knife you used looks like a shaper/moulder knife. In both cases, the speed is too low for efficient profiling. I would also suggest using a safer method.








.
cabinetman is offline  
post #3 of 8 Old 06-25-2011, 05:12 PM Thread Starter
Junior Member
 
Join Date: Jun 2011
Posts: 3
View Sivy's Photo Album My Photos
Preshape was made on lathe with knife for metal cutting.
Nothing is safe there, so I use max 700rpm. I looked at Youtube to see how they use lathe for woodworking. But almost everybody has simple "hand operating" lathe for wood. Those who have metal lathe have no problems with wood cutting. I tried to use standard knifes for metal and they cutting good, but not perfect in merbau wood. Is this wood to hard? Is there any solution to make rounded and decorative corners in wood on metal lathe?
Sivy is offline  
Sponsored Links
Advertisement
 
post #4 of 8 Old 06-25-2011, 11:12 PM
Senior Member
 
Join Date: Sep 2007
Location: Baxter, Tennessee
Posts: 3,257
View john lucas's Photo Album My Photos
It looks to me like you are having chatter problems. That is usually caused by something not being held steady enough. The cutter you are using is probably held well but if you are cutting with the whole surface that's asking a lot of the wood.
Scraping cuts tend to cause chatter worse than cutting tools. You might be better off using a smaller tool to cut the flat surfaces using the cross slide. Then change to a curved cutter for the curved surface and cut just that area.
john lucas is offline  
post #5 of 8 Old 06-26-2011, 02:35 AM
Senior Member
 
Join Date: Feb 2010
Location: Whittier, CA. USA
Posts: 344
View jlord's Photo Album My Photos
I agree with cabinetman. The yellow bit is a router bit & it would give better results in a router turning at 22,000rpm.

James
Whittier, CA.

Just because you can, doesn't always mean you should!
jlord is offline  
post #6 of 8 Old 06-28-2011, 03:09 AM
Senior Member
 
Join Date: Jun 2011
Location: Otautahi , Te WahiPounamu ( Christchurch , New Zealand)
Posts: 1,494
View Manuka Jock's Photo Album My Photos
From the looks of the bottom photo , the wood is being held on a woodworm screw type jig.
That and the low speed will not be helping the situation .
Is the router bit 'gouge' stationary or spinning while in use ?
Manuka Jock is offline  
post #7 of 8 Old 06-29-2011, 03:38 AM Thread Starter
Junior Member
 
Join Date: Jun 2011
Posts: 3
View Sivy's Photo Album My Photos
1) I used router bit only for first cutting test
2) Then I used curved knife on second photo with Merbau wood
3) And then I looked to wood hardness table and found that Merbau is very hard, and now i see my mistake
4) So i take Pine wood, because is soft, and with curved knife everything works fine
5) After tests of cutting wood on metal lathe i see that is possible but slow
6) I made another test: chineese router + chineese bit (that from first photo). Cutting take half of minute. Wood was burned but i know that is poor quality bit fault
7) I keep chineese router but ordered Bosh HM bits and when i get it I made another tests

So, I stop using metal lathe because it's impractical and start using router.

But I have another problem. This wood circle have diameter 8 centimeters. I used bit with guide wheel on bottom, but wood cutted edges was not smooth. It have small waves. It's poor quality bit fault or something else? I keep moving router slow and accuracy and hold it strong but im not happy with quality of cutted edges (for now I working only with Pine wood).
Sivy is offline  
post #8 of 8 Old 06-29-2011, 10:47 AM
Senior Member
 
Join Date: Sep 2007
Location: Baxter, Tennessee
Posts: 3,257
View john lucas's Photo Album My Photos
When using the router bit with guide wheel (or bearing) the wood circle has to be perfect. If there are any dips or sometimes even soft wood the bearing will sink into these and the dip will be transfered to the cut.
Another option is to do away with the bearing and use a V shaped wooden guide. The bit sits in the bottom of the V and the circle will then sit in the V. As you rotate the circle the bit will cut the edge. Keep rotating until the bit doesn't cut anymore. This has the advantage of being able to take lighter passes around the wheels and then readjust the bit in the V to take a deeper cut on the next pass. This will give you a cleaner cut.
john lucas 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



Similar Threads
Thread Thread Starter Forum Replies Last Post
Thin metal wedges for door casing corners bbarkley Trim Carpentry & Built-Ins 25 02-26-2018 11:09 AM
I just couldn't cut the corners off Bill Wyko Woodturning 18 03-22-2011 11:36 PM
making rounded corners for my wooden box boxtalk General Woodworking Discussion 10 01-07-2009 11:30 AM
Rounded Mortise & Squared Tenons? Nickbee Joinery 9 08-13-2008 09:38 AM
Bending 1x8 fascia board on a rounded portch Archie General Woodworking Discussion 11 07-25-2007 09:57 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 Off
Refbacks are Off

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