By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale July 23rd

How does this work.?

All Topics | Latest Posts

Search for:  in Thread Title in  
Nick_G13/01/2016 23:55:02
avatar
1808 forum posts
744 photos

.

What is the reason / physics behind this working.?

Nick
fizzy13/01/2016 23:59:56
avatar
1600 forum posts
106 photos

no idea but im going to try it

ASF14/01/2016 00:17:48
129 forum posts
12 photos

would it be because 1 cutting edge is cutting before the other causing the shaped hole and putting a rag bit in there levels out the cutting edges to stop wander?

John Stevenson14/01/2016 00:53:03
avatar
Moderator
5068 forum posts
3 photos

Dunno but I'll bet he discovered it when his shop coat got caught in the drill. wink

Ady114/01/2016 01:09:21
avatar
3463 forum posts
513 photos

The cloth gathers the swarf and it doesn't get the chance to damage the hole?

Does it work fine without cloth at higher speeds? (lighter swarf)

Edited By Ady1 on 14/01/2016 01:10:03

Dinosaur Engineer14/01/2016 01:28:34
144 forum posts
4 photos

This "trick" is as old as the hills. I was taught this by an old toolmaker in the mid 50's ! The emery cloth puts a small chamfer on the edge of the hole before the drill starts cutting and it stops the drill from biting too quickly. Also the cloth supports the drill between the 2 cutting points and minimises the drill wandering from the proper circular path. 3 flute drills are much better at drilling thin material as the drill is supported by 3 points and not 2. The method shown does result in a hole slightly bigger than the drill because of the extra material taken out by the emery. Clamping some thicker scrap material on top of the thin material to be drilled will give the drill better support and minimise any "wandering" by the drill and gives better hole dia. control..

Muzzer14/01/2016 08:12:10
avatar
2904 forum posts
448 photos

Doesn't say (or look like) emery cloth - just a bit of thing cotton sheet perhaps.

As ASF suggests , I guess it's damping out the vibrations that result from the bit dancing about while cutting a non-circular hole. Just enough drag to dampen its enthusiasm. The drill centre must be jigging about nicely when it's making those trianguar holes.

Edited By Muzzer on 14/01/2016 08:29:48

Edited By Muzzer on 14/01/2016 08:33:52

Michael Gilligan14/01/2016 08:48:36
avatar
13781 forum posts
599 photos
Posted by Muzzer on 14/01/2016 08:12:10:

Doesn't say (or look like) emery cloth - just a bit of thing cotton sheet perhaps.

.

I've not tried it with normal drills, but that certainly calms-down chattering countersinks.

MichaelG.

Edited By Michael Gilligan on 14/01/2016 08:49:23

Martin Kyte14/01/2016 08:54:18
1472 forum posts
24 photos

I would concur with the last two posts with the additional comment:-

It's about getting an accurate start to the hole. Once that has been achieved the hole progresses correctly. Basically it stops the tips of the cutting edges grabbing and throwing the drill off centre. Once this has happened the drill follows the odd shaped hole all the way through.

regards Martin

jason udall14/01/2016 08:56:34
2010 forum posts
41 photos
Not certain

My belief is that in part damping and support for the point of the drill...stabilization.

Its old..saw it listed as tip-dodge..in 1800's book..old then...
David Clark 114/01/2016 10:40:42
avatar
3357 forum posts
112 photos
10 articles

Just drill hole a bit undersize and finish with a slot drill.

Chris Evans 614/01/2016 10:55:36
1448 forum posts

That was one of the first things shown to me when I started my tool making apprenticeship in 1963. We never questioned how it worked, just applied the method of a bit or worn emery cloth.

Gordon W14/01/2016 11:44:23
2011 forum posts

I've always assumed the cloth or emery cloth fills the flutes up, so creating a "solid" tip that works a bit like an end mill.

Dinosaur Engineer14/01/2016 15:43:30
144 forum posts
4 photos

The method will work with ordinary cloth but works better with fine to meduim emery cloth.

Edited By Dinosaur Engineer on 14/01/2016 15:44:52

mick14/01/2016 17:12:00
384 forum posts
44 photos

It fills the flutes and stops the web wandering when it starts to bite, use worn out emery tape folded double with the grit faces inwards, the resulting hole will be round but slightly oversize.

Nigel McBurney 114/01/2016 17:34:09
avatar
585 forum posts
3 photos

I was shown this trick many years ago,the method was to use a small piece , rag folded over and over to get 8 thicknesses, works well on thin sheet ,the rag fills up the flutes and makes the drill work like a reamer,

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Warco
ChesterUK
Ausee.com.au
Advertise With Us
Eccentric July 5 2018
TRANSWAVE Converters
Eccentric Engineering
Meridienne Sept 2019
Allendale Electronics
emcomachinetools
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest