UK Caving

TECHNICAL FORUMS => Digging => Topic started by: TMan on October 03, 2019, 10:23:56 am

Title: Punches instead of Plug and Feathers
Post by: TMan on October 03, 2019, 10:23:56 am
Hi,

ever used Punches instead of Plug and Feathers?
Like this https://pixabay.com/photos/tool-centre-punch-metal-steel-2523806/

I used some with a very small drillling diamater (8mm) and it worked relatively good.....
Advantages: very cheap (<1 Euro), small diameter.
Disadvantages: less effect

Cheers
Title: Re: Punches instead of Plug and Feathers
Post by: TMan on October 09, 2019, 06:20:01 pm
Anybody?
Title: Re: Punches instead of Plug and Feathers
Post by: thomasr on October 09, 2019, 06:30:37 pm
As an example  drilling a round hole  in a piece of say perspex would have the effect of limiting a split/ fissure spreading further.  So drilling in to rock and punching  is   sending the presure force out evenly in all directions and generally is much less effective . Nevertheless it can and does work
Title: Re: Punches instead of Plug and Feathers
Post by: Pitlamp on October 10, 2019, 10:58:50 am
An interesting idea, TMan; thanks for posting. One other advantage you didn't mention is that minimal drilling is needed for the hole (i.e. save on battery energy).

But . . . prompted by on ThomasR's point, if a line of "relief holes" is drilled, either side of the hole to take the conical punch, it will have much greater effect (think old tax disc, which you tore out along a line of tiny perforations).

Another thing which would improve effectiveness is drilling the hole or holes a lot deeper than necessary to accept the hammered in punch. (This principle also applies to traditional plugs & feathers of course.)
Title: Re: Punches instead of Plug and Feathers
Post by: Fishes on October 10, 2019, 01:19:55 pm
Effective lubrication seems to make a big difference with plug and feathers. I don't know how effective it would be here.

Mel Milner was a big fan of drilling several small holes and driving in a standard chisel and seemed to have some success with that. I don't know if anyone is still using that technique.
Title: Re: Punches instead of Plug and Feathers
Post by: Pitlamp on October 10, 2019, 01:21:51 pm
The late Keith "Ben" Bentham was a pastmaster at that. He's also the only person I ever saw drill a hole with a standard chisel (as opposed to a star drill, for those who still know what they are).
Title: Re: Punches instead of Plug and Feathers
Post by: Fishes on October 10, 2019, 01:26:41 pm
Star drills - now you are making me feel really old. I think I still have some somewhere.
Title: Re: Punches instead of Plug and Feathers
Post by: Fulk on October 10, 2019, 01:34:51 pm
(as opposed to a star drill, for those who still know what they are)

I remember hanging my butt out over the big pitch in Long Drop Cave to drill a hole for a 1-inch Rawlbolt with a star drill . . . it took about an hour.
Title: Re: Punches instead of Plug and Feathers
Post by: Pitlamp on October 10, 2019, 01:41:10 pm
Star drills - now you are making me feel really old. I think I still have some somewhere.

I bought some not that long ago - they have their uses in certain caving situations.

Fulk - only an hour? I'm seriously impressed with your drilling ability!
Title: Re: Punches instead of Plug and Feathers
Post by: yuvals on October 10, 2019, 04:18:27 pm
As you said, it less efficient and more prone to get stuck in the rock in case it not break it.

Since it is less efficient, you will have to drill closer holes (=more drills), so I don't think you save battery.

Nowadays, you can get cheep Plug and Feathers for about 1 Euro on AliExpress so, in my option, you better use Plug and Feathers.
 
Title: Re: Punches instead of Plug and Feathers
Post by: Fulk on October 10, 2019, 06:25:43 pm
Quote
Fulk - only an hour? I'm seriously impressed with your drilling ability!

Hmmmmm . . . is that a double-entendre?  :lol:
Title: Re: Punches instead of Plug and Feathers
Post by: Pitlamp on October 10, 2019, 06:57:31 pm
It depends on how your mind works . . .  ;)
Title: Re: Punches instead of Plug and Feathers
Post by: TMan on October 10, 2019, 07:01:56 pm
Thank you for your answers.
Plugs and feathers distribute the power also almost only in a circle.
Sure, the punches need smaller holes, which means small, lightweight machine (like the uneo), higher probability that you can pack it waterproof etc .... to drill holes deeper than required generates a breaking line.
I tried this method in a row, 5 punches, that worked quite well so far.
Nowerdays there are a lot of very good techniques...straws, micro-straws, time or parallel ignitors, plug and feathers, capping or modified externel capping (with detaupeurs or better and cheaper homemade detaupeurs), punches, swelling cement, kind of window openers.....every method has its advantages and disadvantages and its right to exist....golden age of enlargement. :clap2:
Title: Re: Punches instead of Plug and Feathers
Post by: thomasr on October 10, 2019, 08:06:28 pm
Correct me if Im wrong but plugs and feathers tend to excert their force in 2 directions  forcing apart a fracture .IT is round punches in a drilled hole that try to split the rock in all directions so requiring a lot of effort
Title: Re: Punches instead of Plug and Feathers
Post by: Fishes on October 10, 2019, 10:50:49 pm
From my experience plug and feathers are directional.
Title: Re: Punches instead of Plug and Feathers
Post by: Roger W on October 10, 2019, 11:15:32 pm
Surely with plug and feathers you are hammering the plug down between the feathers and forcing them apart and outwards.  Arrange your feathers in the right position, and the resulting force will be applied to split the rock in the right direction.

As has been pointed out, simply hammering a tapered plug (punch) into a round hole will apply an outward force in all directions, tending to split the rock along its weakest line - maybe a pre-existing crack or a bedding plane, or where you have created a weakness by drilling a row of holes.

I think the feathers play a vital role in providing direction to the forces generated by hammering in the plug.