Centering a square cap jig - Router Forums
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 16 (permalink) Old 04-20-2012, 10:11 AM Thread Starter
Registered User
 
Join Date: Jul 2011
Country: Canada
First Name: Steve
Posts: 5
 
Default Centering a square cap jig

Hello all, may I pick your brains?

I work for a large stair manufacturer and we've been racking multiple brains to come up with a simple, efficient jig for the following:

A specific style of post we make requires that we pre-drill in the exact center of the underside of the post cap. They are always square, but come in varying sizes, and these sizes sometimes have a 16th variance due to shrinkage. What we're trying to come up with is a jig for use with a drill press that would center the drill bit on the cap regardless of differences in size, for rapid mass-production. If they were all identical all the time it would be no problem.

The ideas we've come up with so far have either been far too complicated, awkward to employ, or require advanced engineering techniques we're not sure exist...

Any ideas here?
safetysteve403 is offline  
Sponsored Links
Advertisement
 
post #2 of 16 (permalink) Old 04-20-2012, 08:47 PM
Registered User
 
CharleyL's Avatar
 
Join Date: Feb 2009
Country: United States
First Name: Charley
Posts: 1,996
 
Default

Carefully drawn lines from opposite corners will form an X in the exact center. Then drill your hole there. A jig isn't necessary. Another possibility is to use a lathe center marking jig like this one, but it won't work very well if the cap isn't perfectly square.


Amazon.com: Woodstock D3098 Center Finder: Home Improvement


Charley

Central North Carolina
CharleyL is offline  
post #3 of 16 (permalink) Old 04-20-2012, 09:15 PM
Registered User
 
Join Date: Aug 2011
Country: Japan
First Name: singh kuldeep
Posts: 136
 
Send a message via Skype™ to samurai
Default

bridge city thet have drilling jig for this kind of task.expensive but very nice.have a look on video
samurai is offline  
Sponsored Links
Advertisement
 
post #4 of 16 (permalink) Old 04-20-2012, 11:01 PM
Registered User
 
Join Date: Jun 2011
Country: United States
First Name: Duane
Posts: 1,709
 
Default

A large version of this?
Attached Thumbnails
Click image for larger version

Name:	pen-vise_l.jpg
Views:	103
Size:	82.0 KB
ID:	51784  

Dmeadows is offline  
post #5 of 16 (permalink) Old 04-21-2012, 07:00 AM
Registered User
 
Join Date: Nov 2011
Country: United States
First Name: N/a
Posts: 39
 
Default

How about this? Make a square box with no bottom or top that is ~1/2" larger than your largest cap. Make the sides tall enough to contact the flat edges of the cap. Center this under the drill bit on the drill press. When you insert the cap to be drilled, rotate it so all 4 corners are touching the sides of box and you will be centered.
michmags is offline  
post #6 of 16 (permalink) Old 04-21-2012, 08:46 AM
Registered User
 
Join Date: Aug 2011
Country: Canada
First Name: Andy
Posts: 106
 
Default

Try rilling the hole then squaring the top from a centre pin tahtshould be perfect
Andy
andy's Den is offline  
post #7 of 16 (permalink) Old 04-21-2012, 08:46 AM
Registered User
 
Join Date: Jan 2012
Country: United States
First Name: Art
Posts: 1,443
 
Default

Instead of trying to center different size stock why not plan each post to a standard size and then go from there.
mgmine is offline  
post #8 of 16 (permalink) Old 04-21-2012, 07:32 PM
Registered User
 
JOAT's Avatar
 
Join Date: Apr 2010
Country: United States
First Name: Theo
Posts: 6,088
 
Default

Quote:
Originally Posted by CharleyL View Post
Carefully drawn lines from opposite corners will form an X in the exact center. Then drill your hole there. A jig isn't necessary.
Yep, that's the way I'd go. You guys apparently forgot the acronym K.I.S.S.
Keep It Simple Stupid.
JOAT is online now  
post #9 of 16 (permalink) Old 04-21-2012, 08:15 PM
Registered User
 
rwl7532's Avatar
 
Join Date: Sep 2011
Country: United States
First Name: Ralph
Posts: 1,288
 
Default

Quote:
Originally Posted by safetysteve403 View Post
for rapid mass-production.
Looks to me that many replies have missed this phrase.

How many seconds each cycle? (Item into jig and desired adjustment time until drilling begins)

Last edited by rwl7532; 04-21-2012 at 08:29 PM. Reason: the word "many"
rwl7532 is offline  
post #10 of 16 (permalink) Old 04-21-2012, 08:52 PM
Registered User
 
Join Date: Dec 2010
Country: United States
First Name: Tom
Posts: 310
 
Default

Quote:
Originally Posted by michmags View Post
How about this? Make a square box with no bottom or top that is ~1/2" larger than your largest cap. Make the sides tall enough to contact the flat edges of the cap. Center this under the drill bit on the drill press. When you insert the cap to be drilled, rotate it so all 4 corners are touching the sides of box and you will be centered.
Think you're on to something but the box should probably have some sort of leveling "shelf" to allow a bore square to the plane of the cap. The jig can have a centered peg that aligns with the bit on the drill press. (think pin routing)

If the caps have a profile on top that hinders a flat just drop it in and turn motion then the boring might be better done from below.
TomE 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
Porter Cable 55160 Omnijig Review Echonav Tool Reviews 19 06-21-2015 03:59 AM
Shelf pin hole jig - reviews and router solution Greg_R Jigs and Fixtures 17 04-24-2014 09:02 PM
Akeda BC24 Dovetail Jig arrived! Michael H Jigs and Fixtures 13 04-11-2012 10:50 PM
First Box Joints w/a Hart Design Jig Wild Rag Jigs and Fixtures 2 03-23-2009 09:54 AM
Hinge mortising question Dalec Jigs and Fixtures 8 03-02-2009 07:17 AM

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