Need Help With A Bit/Bushing Combo - Router Forums
 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 07-02-2011, 12:39 PM Thread Starter
Registered User
 
AzViper's Avatar
 
Join Date: Apr 2011
Country: United States
First Name: Keith
Posts: 79
 
Default Need Help With A Bit/Bushing Combo

I have a question I am hoping someone can answer. I am having an elliptical poker table cut on a CNC router using a 1/2" double fluted bit. The center cutout as seen in figure C will be 71" by 22" on the outer edge and the leftover piece should be 70" by 21". I need to use this 70" by 21" as a template to cut a slightly larger center piece of 70"-3/8" by 21"-3/8". What router bit / bushing combination should I use it there is such a combination. In the past I would just cut this using my circle jig but I am now having to use a bit / bushing combo as I need to use a template due to being an elliptical cutout.

I would have used a 1/2" shank bit that had a cutting surface of 5/16" by 1" on the CNC router as this would leave the cutout with the 5/16" gap I need, but I cannot find a bit locally without ordering it and with the holidays upon us I need it for next Wednesday. My only option is to use a bit / bushing. With elliptical if we were to set up the CNC router to make this cut the outside edge will not maintain a 5/16" gap once this center section is placed back into the original cutout due to the inherited issues with elliptical cutouts.

Hope this makes sense. When building a poker table we have what we call a racetrack table with a center playing surface as seen in the photo. Its the gap between the racetrack and the center playing surface that I need to maintain a 5/16" before foaming and applying the cloth.




Last edited by AzViper; 07-02-2011 at 01:39 PM.
AzViper is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old 07-02-2011, 01:45 PM
Registered User
 
Phil P's Avatar
 
Join Date: Jul 2010
Country: United Kingdom
First Name: Phil
Posts: 2,117
 
Default

Quote:
Originally Posted by AzViper View Post
I need to use this 70" by 21" as a template to cut a slightly larger center piece of 70"-3/8" by 21"-3/8". What router bit / bushing combination should I use it there is such a combination.
Hi Keith

3/8in overall larger translates to a 3/16in offset from the edge of template to the cutter. The router cutter combination needs to be diam of router + 2 x 3/16in; so your 1/2in cutter could therefore work with a 7/8in guide bush, if you can get one that is. Alternatively a 3/8in cutter would achieve the same effect with a 3/4in guide bush, and I know they're available.

I think that makes sense

Regards

Phil
Phil P is offline  
post #3 of 5 (permalink) Old 07-02-2011, 01:58 PM Thread Starter
Registered User
 
AzViper's Avatar
 
Join Date: Apr 2011
Country: United States
First Name: Keith
Posts: 79
 
Default

Quote:
Originally Posted by Phil P View Post
Hi Keith

3/8in overall larger translates to a 3/16in offset from the edge of template to the cutter. The router cutter combination needs to be diam of router + 2 x 3/16in; so your 1/2in cutter could therefore work with a 7/8in guide bush, if you can get one that is. Alternatively a 3/8in cutter would achieve the same effect with a 3/4in guide bush, and I know they're available.

I think that makes sense

Regards

Phil
Thank you Phil. I have entire set of bushings and I have both the bushing you spoke of. Good news though, I found a 1/2" shank bit with a 5/16" x 1" cutter. This completely solves my problem as the router vacuum will suck the plywood down and the 5"16" cutter will leave me the 5"16" gap I need without buying another sheet of plywood and using the bit / bushing combo with the template.
AzViper is offline  
Sponsored Links
Advertisement
 
post #4 of 5 (permalink) Old 07-02-2011, 08:45 PM Thread Starter
Registered User
 
AzViper's Avatar
 
Join Date: Apr 2011
Country: United States
First Name: Keith
Posts: 79
 
Default

Well after speaking to my friend who owns the CNC router what he told me makes more sense then buying the 5/16" router bit. He is going to write the program to plunge cut with a 1/4" bit making multiple passes to cut through the entire sheet. Then on the racetrack side of the plywood with the CNC router bit at its full depth to trim 1/32" off and repeat this on the center section to give me my 5/16" gap. He says you never want to plunge a start and stop but to do a circular lead in with a cutter as the finish product is better and will have a smoother finish.

Bottom line I have been beating myself up over this when he had it under control...
AzViper is offline  
post #5 of 5 (permalink) Old 07-03-2011, 05:25 AM
Registered User
 
Phil P's Avatar
 
Join Date: Jul 2010
Country: United Kingdom
First Name: Phil
Posts: 2,117
 
Default

Hi Keith

Ramped entry cut is smoother and places less strain on the cutter as well. Also allows you to use a non plunge cutter for what is essentially a plunge operation

Regards

Phil
Phil P 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
Rigid Model R2900 Router Combo and Ryobi Model A25RT02 Router table bigdave720 Table-mounted Routing 12 04-05-2012 08:27 PM
Milwaukee 18V drill+driver combo crquack Tools and Woodworking 1 03-05-2010 07:17 AM
Craftsman Combo bill0199 General Routing 17 06-20-2009 10:25 AM
Ridgid Router Combo R2390 homebrewer27 General Routing 28 04-28-2008 10:45 PM
Stapler vs. Nailer/Staple combo rprice54 Tools and Woodworking 4 06-08-2006 07:39 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