Re: make - forge? - wedge for feathers-and-wedge rock-split

On 14/06/2024 09:54, Richard Smith wrote:

Richard Smith <null@void.com> writes:
>

Hello all
>
Setting the scene:
>
"feathers" work well for splitting boulders so can be removed as
handleable rocks.
Lots of videos online eg. YouTube how to use them.
>
The ones I have:
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http://www.weldsmith.co.uk/tech/minerals/pics/240314_feathers_holes.jpg
>
from page
http://www.weldsmith.co.uk/tech/minerals/240314_rocksplit/240314_rocksplit_drill_feathers.html
"Rock-split granite with "cordless" SDS drill and "feathers""
>
They work really well.
But these "10mm" feathers need a 14mm-dia socket.
The wedge is visibly oversized=overthickness for the feathers.
Saving just two mm of thickness would surely enable using a 12mm
socket.  Useful saving on drilling (14mm -> 12mm)
(/ (expt 12 2) (float (expt 14 2))) ;; 0.7346938775510204
73% of vol drilled - and the impact is concentrated on the smaller
cutting tip.
>
>
The question:
>
How would you go about producting wedges about 2mm to 3mm thinner than
the current ones?
>
Doing something to the current wedges would be okay.
>
Making them anew with something like forging could be a good project.
If so what steel would you use?  AISI1075? (C-Mn; 0.75%C).  If so -
"spring-temper"?
>
We have something called "silver steel" which is "(centreless-?) ground
0.8%C steel" (ie. right on the eutectoid).
>
Always appreciated the range of knowledge here.
>
Regards,
Rich Smith

>
Follow-up, for what it's worth...
>
This is about my "10mm" (~ 3/8inch) rock-splitting feathers.
>
As-supplied, they need a 14mm diameter socket to fit-in in the rock you
want to split.
>
I ground three wedges thinner so they will fit in a 12mm socket.
Which I have been the "feathers" I have used for breaking up "rocks"
lying-about in the hobby mine.
The request is : preferably don't send rocks in the skip up the haulage
shaft which are much bigger than a loaf of bread.
>
So I have been rapidly drilling-in a couple or three sockets in stones
and splitting them "rapidly" - skip-loads to surface (given our "mine"
is tiny and so is the skip in the haulage-shaft).
>
Recent finding for "boulders" which are bigger than two people could
carry...
>
You need the stiffness of the wedges in the feathers-and-wedge's
as-supplied.
So that was got right as-supplied.
>
My SDS "cordless" battery-powered drill is fast at 12mm but definitely
taking more than pro-rata longer at 14mm.
Mustn't make dust down in the mine, as the fine silica dust would
circulate around and be breathed-in by everyone.
So must drill under water-flood (keeps the drill cool, too).
Nett...
>
Go around your boulder with a pilot-drill size, doing the various planes
along which you intend to split it, then go around again with the 14mm
drill, then use the feathers lined along each plane to do the splitting.
>
Seems 7mm pilot-hole size would be ideal
* 6mm too small - the SDS cordless drill can "over-power" it into the
hard granite and a moment's inattention can have it red-hot then
destroyed.
* 8mm drills well but maybe unnecessarily large
Unfortunately (?) masonry drill sizes go in 2mm increments.  So I have
to go with 8mm.
>
The one about water-flood - if the drilling is going at a good rate,
it takes less concentration and you can be happily holding the
water-bottle in the other hand, squeezing a fast fine jet through a
small hole in the lid which sprays onto the rotating drill at the point
it goes into the rock.
>
Yesterday a mining engineer and a civil engineer watched how I split a
boulder...
Seem to be doing something right...
>
Thanks for the help the nearly 3 months ago when I was trying for find
my way with this.
>
Rich Smith

As all the masonry bits I've ever had have the TC insert sticking out the sides of the shank I was going to suggest narrowing an 8mm bit to nearer 7mm with a diamond or green wheel, my 8mm bit measures 8.25mm across the TC insert and the shank is 7.1mm. That being said a quick search for 7mm masonry bits turns up plenty of them and they seem to be readily available from many sources.