What drill bit size to use? - Page 3 - diyAudio
Go Back   Home > Forums > Design & Build > Construction Tips

Construction Tips Construction techniques and tips

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th January 2012, 02:03 AM   #21
diyAudio Member
 
kevinahcc20's Avatar
 
Join Date: Apr 2009
Location: Farmington Hills, MI USA
If you have 12 year old JD it's been sitting in the liquor cabinet waaaay too long!!
__________________
Kevin(ahcc20)...I'd rather have a bottle in front of me than a frontal lobotomy!
  Reply With Quote
Old 10th January 2012, 03:25 AM   #22
Lavcat is offline Lavcat  United States
diyAudio Member
 
Lavcat's Avatar
 
Join Date: Dec 2009
Location: New Jersey USA
Quote:
Originally Posted by vinylkid58 View Post
Larger.

jeff

Thanks, but by how much exactly. I'm sitting here with the 23rd edition of Machinery's Handbook. I know the answer is probably in there somewhere but I cannot find it.
  Reply With Quote
Old 10th January 2012, 06:49 AM   #23
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Quote:
Originally Posted by Lavcat View Post
Thanks, but by how much exactly.
0.010-0.015" is usually fine. I remember buying the 23rd edition when it was new. How time flies.

jeff
  Reply With Quote
Old 10th January 2012, 06:59 AM   #24
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Quote:
Originally Posted by Lavcat View Post
Thanks, but by how much exactly. I'm sitting here with the 23rd edition of Machinery's Handbook. I know the answer is probably in there somewhere but I cannot find it.
Do you want a "close fit" or a "free fit"?

Tapping and clearance hole table
  Reply With Quote
Old 10th January 2012, 07:13 AM   #25
Lavcat is offline Lavcat  United States
diyAudio Member
 
Lavcat's Avatar
 
Join Date: Dec 2009
Location: New Jersey USA
Quote:
Originally Posted by 454Casull View Post
Do you want a "close fit" or a "free fit"?

Tapping and clearance hole table

Close fit. Stanford I see does not do metric.
  Reply With Quote
Old 10th January 2012, 07:25 AM   #26
Lavcat is offline Lavcat  United States
diyAudio Member
 
Lavcat's Avatar
 
Join Date: Dec 2009
Location: New Jersey USA
Quote:
Originally Posted by vinylkid58 View Post
0.010-0.015" is usually fine. I remember buying the 23rd edition when it was new. How time flies.

jeff
So then something like a 0.1260 inch drill?


Edit: I found this chart that says 0.125 inch.

http://www.physics.harvard.edu/servi...hreadChart.pdf


But what would a more metric person do?

Last edited by Lavcat; 10th January 2012 at 07:44 AM.
  Reply With Quote
Old 10th January 2012, 10:21 AM   #27
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
******* hell!!!
An M3 bolt/thread is 3mm nominal outside diameter. But the tips of the male thread are rounded. I can't recall the radius, but it will be in the data.
The M3 bolt thread will pass through a clean exactly 3mm diameter hole.
The shank of a M3 bolt will be 3mm +-tolerance. That tolerance may make for a very tight fit, or a very slack fit in an exactly 3mm diameter hole. But the hole also has tolerances. Not least, that a 3mm drill measures smaller than 3.000mm.

0.126" = 3.2004mm
0.125" = 3.175mm
You could throw an M3 at these hole diameters and there's a good chance that the thread will fall through.

Wake up and get your calculators out, if you can't visualise 3mm.
__________________
regards Andrew T.
  Reply With Quote
Old 10th January 2012, 01:42 PM   #28
diyAudio Member
 
kevinahcc20's Avatar
 
Join Date: Apr 2009
Location: Farmington Hills, MI USA
Quote:
Originally Posted by Lavcat View Post
Thanks, but by how much exactly. I'm sitting here with the 23rd edition of Machinery's Handbook. I know the answer is probably in there somewhere but I cannot find it.
There is no single correct answer for this one - in fastener engineering (my 1st job in the auto industry) this decision is driven by two factors. The larger the clearance hole the easier assembly will go (assuming there are multiple fasteners) as the larger clearance allows for slight misalignment in hole locations between the mating pieces while still passing the fastener. The smaller clearance hole provides more load bearing area (the area between the OD of the fastener head and the ID of the clearance hole) which is critical in highly stressed attachments to avoid brinnelling of the surface under the fastener head, which can compromise the attachment.

Generally in our hobby we rarely encounter highly stressed attachments carrying large cyclic loads...perhaps to some extent in some speaker structures. So you want to basically decide with what precision you are able to locate the holes in the two (or more) mating pieces. If you can work to +/- 0.1 mm in locating and drilling all of the holes relative to design location then you will need 0.2 mm of clearance to allow all of the fasteners to pass. When finished this would provide a workmanlike appearance.

One way to get nice results while sort of cheating this process is to drill all of the holes in one of the mating parts, clamp them together in design relationship, and use a transfer punch to locate the hole centers in the mating part. A transfer punch has an OD matched to the clearance hole size and a point in the center. This way the small errors in hole location on the 1st part get duplicated on the second and you can use a tight clearance hole since you are not trying to allow for the two errors to stack at each hole.
__________________
Kevin(ahcc20)...I'd rather have a bottle in front of me than a frontal lobotomy!
  Reply With Quote
Old 10th January 2012, 05:05 PM   #29
Lavcat is offline Lavcat  United States
diyAudio Member
 
Lavcat's Avatar
 
Join Date: Dec 2009
Location: New Jersey USA
Quote:
Originally Posted by AndrewT View Post
******* hell!!!
An M3 bolt/thread is 3mm nominal outside diameter. But the tips of the male thread are rounded. I can't recall the radius, but it will be in the data.
The M3 bolt thread will pass through a clean exactly 3mm diameter hole.
The shank of a M3 bolt will be 3mm +-tolerance. That tolerance may make for a very tight fit, or a very slack fit in an exactly 3mm diameter hole. But the hole also has tolerances. Not least, that a 3mm drill measures smaller than 3.000mm.

0.126" = 3.2004mm
0.125" = 3.175mm
You could throw an M3 at these hole diameters and there's a good chance that the thread will fall through.

Wake up and get your calculators out, if you can't visualise 3mm.

I used to be a scientist, I can visualize 3 mm. If not I have my Mitutoyo machinist's ruler sitting here. Three millimeters is approximately a third of a barleycorn for what it's worth.

My plan is to make a reamed hole. Reamers are expensive and I was hoping to get the correct size the first time rather than going for trial and error.

What 3 mm bit measures smaller than 3.000mm? Where I have seen a diameter tolerance listed it is usually +something, -zero.
  Reply With Quote
Old 10th January 2012, 05:10 PM   #30
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
And what exactly are you doing with those 3mm holes? Are you building a rocket?
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Broken drill bit in chuck gmphadte Equipment & Tools 14 14th September 2007 04:19 AM
Denon DCD 1520 20-bit or 18-bit? beauty_divine Digital Source 0 9th September 2007 06:41 AM
To drill or not to drill? (a VPI turntable) m.parigi Analogue Source 5 6th January 2006 02:32 AM
24 bit I2S source to 16 bit DAC? chris719 Digital Source 5 18th June 2005 05:24 PM
use digital attenuation to improve 16-bit CD playback on 24 bit DAC capslock Digital Source 7 8th April 2002 11:18 PM


New To Site? Need Help?

All times are GMT. The time now is 07:26 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2