discomark10
Well-Known Member
I was going to try a centre to be honest and if that failed a centre cross with a small grinder wheel.
I got a 5mm to start it off and a 10mm for finish.
I got a 5mm to start it off and a 10mm for finish.
easye1
Banned
i know its dangerous to do, but have center popped hard stuff using a tap with no.1 start on it.
most have a ground point, but please bash it with a soft mallet /copper or brass one and wear glasses because it can shatter the hard tap material..
easye1
Banned
yes more like that, but if you look at the darker and lighter clearance angles, they had a back cut towards the center either side also, like another little vertical flat looking at it that way..
but i dont think you will get away with a tipped drills cutting edge, it`ll shatter or crumble..
I agree with you on the tipped drill bit. Think you described a 6 faceted grind. Like a back angle towards center creating like a center drill type center
gemsdad
NOT BOTHERED.
you know eh......
dont do pictures, but some of my drill bits have a cross cut either side of the "flat centre" part of the drill point for use on very hard materials..
think it reduces the friction areas/ allows more coolant/lubricant access to point of cutting areas..
something like this
How to sharpen cobalt drill bits | eHow UK
how to resharpen cobalt drills - Searchya - Search Results Yahoo Search Results
yes mate i do,i worked on lathes for GEC traction and turbines in Trafford park,now long gone,but i have lost count of the drills/cutting tools i have sharpened,or modified for certain jobs/metals.
easye1
Banned
thats old school engineers for you eh.....lol
our old firm was called G.E.C.
but General Engineering Company (Ilford) LTD
wammers found a plane "we owned" at one time..
traded for over 60 years on its site.
was a new purpose built factory post war on a newly established Industrial estate funded by the old GLC.
they also built housing for the estates workers.
the factory site now sell bloody new rangies, landies and jags from its prominant position on the main roads there now......
they wont have any trouble with the floors, most were "rafts" of over a metre deep set in noise reduction material to stop transmitted & recieved vibration for each very big machining center....
still have a nose in the shutter rear/side doors when I drive past, in the hope of seeing the plant in there...
all gone and replaced with motor stuff...and blokes in clean overalls - not a "real" firm at all....
gemsdad
NOT BOTHERED.
thats old school engineers for you eh.....lol
our old firm was called G.E.C.
but General Engineering Company (Ilford) LTD
wammers found a plane "we owned" at one time..
traded for over 60 years on its site.
was a new purpose built factory post war on a newly established Industrial estate funded by the old GLC.
they also built housing for the estates workers.
the factory site now sell bloody new rangies, landies and jags from its prominant position on the main roads there now......
they wont have any trouble with the floors, most were "rafts" of over a metre deep set in noise reduction material to stop transmitted & recieved vibration for each very big machining center....
still have a nose in the shutter rear/side doors when I drive past, in the hope of seeing the plant in there...
all gone and replaced with motor stuff...and blokes in clean overalls - not a "real" firm at all....
I once said to a young engineer that i could drill a bigger dia hole with the drill bit he was using ,he refused to believe me,until i showed him how,the look on his face was a picture.
discomark10
Well-Known Member
Hi guys, got a chance to have a play with the drills today on my test gear.
Well.. I stated a spot with a centre drill to start then the small 5mm drill had the tip snap before it got to the bottom, not 100% sure why, but it got pretty annihilated lol.
The 10mm drill did very well, started itself fine and drilled very well as you can see from the pic.
I stopped before I got to the bottom and drilled out the splined part with a old 10mm HSS drill.. which didnt last long!
I drilled another hole and as I got to the bottom, the intermittent cut of the spline then ruined the tip.
I found a random cheap masonary drill to try and I was shocked how well it did, it was clearly blunt to start with but did it fine!
Until I hit the splines again.
I've ordered a couple masonary drills to do the real gear, going to finish the holes with the HSS drill as I'm not fussed about that.
For reference, a diamond drill..
Thats as far as I got before it failed.
Also had bash at my mandrel for the pipe bender I'm making while I was at it.
Not sure why but the sound didn't work..?
http://vid1262.photobucket.com/albums/ii610/Silverxxx670/20141214_143517_zpsgaqgqmhb.mp4
I was using a fly cutter.
Well.. I stated a spot with a centre drill to start then the small 5mm drill had the tip snap before it got to the bottom, not 100% sure why, but it got pretty annihilated lol.
The 10mm drill did very well, started itself fine and drilled very well as you can see from the pic.
I stopped before I got to the bottom and drilled out the splined part with a old 10mm HSS drill.. which didnt last long!
I drilled another hole and as I got to the bottom, the intermittent cut of the spline then ruined the tip.
I found a random cheap masonary drill to try and I was shocked how well it did, it was clearly blunt to start with but did it fine!
Until I hit the splines again.
I've ordered a couple masonary drills to do the real gear, going to finish the holes with the HSS drill as I'm not fussed about that.
For reference, a diamond drill..
Thats as far as I got before it failed.
Also had bash at my mandrel for the pipe bender I'm making while I was at it.
Not sure why but the sound didn't work..?
http://vid1262.photobucket.com/albums/ii610/Silverxxx670/20141214_143517_zpsgaqgqmhb.mp4
I was using a fly cutter.
Last edited:
easye1
Banned
I once said to a young engineer that i could drill a bigger dia hole with the drill bit he was using ,he refused to believe me,until i showed him how,the look on his face was a picture.
LOL>.....
only just seen this post....
of subject bit I also done a lot of sandvik coromant "deep hole" drilling on adapted long bed lathes...........the noise was - LOUD..
easye1
Banned
Hi guys, got a chance to have a play with the drills today on my test gear.
Well.. I stated a spot with a centre drill to start then the small 5mm drill had the tip snap before it got to the bottom, not 100% sure why, but it got pretty annihilated lol.
The 10mm drill did very well, started itself fine and drilled very well as you can see from the pic.
I stopped before I got to the bottom and drilled out the splined part with a old 10mm HSS drill.. which didnt last long!
I drilled another hole and as I got to the bottom, the intermittent cut of the spline then ruined the tip.
I found a random cheap masonary drill to try and I was shocked how well it did, it was clearly blunt to start with but did it fine!
Until I hit the splines again.
I've ordered a couple masonary drills to do the real gear, going to finish the holes with the HSS drill as I'm not fussed about that.
For reference, a diamond drill..
Thats as far as I got before it failed.
Also had bash at my mandrel for the pipe bender I'm making while I was at it.
Not sure why but the sound didn't work..?
http://vid1262.photobucket.com/albums/ii610/Silverxxx670/20141214_143517_zpsgaqgqmhb.mp4
I was using a fly cutter.
well at least your getting different options on choice of drill bit...
and, a hole is a hole eh....
the fly cutter, was it the centre part to look at, as if it was, the feed was just about right, not too progressive, and not rubbing too much...
bet it sounded like
chomp-chomp-chomp-chomp-chomp...
discomark10
Well-Known Member
Yes, the centre bit.
I had the tool going fairly fast, its only a corner of a 5mm square tool steel.
IIRC that was 3 passes to get to that point, and it wasn't to bad of a sound.
But yes, a fast chomp, chomp, chomp lol
Need to decide the nominal diameter of the tube I'm going to be using so I can finish it off.
Yes, it always seems to be the breaking through part that chips bits out of the drill tip. You had the splines to help put some serious stress on the drill but I've had it happen to me just breaking through flat surfaces. That's why I tend to use ordinary masonry drills and put a cutting edge on them with a green grit wheel and away I go. The drill is often sacrificed, but as they're ordinary masonry bits they're not expensive and readily available.
discomark10
Well-Known Member
lil xmas gift...
