Wood drill splitting block

[ZDP-189]

I'm using this 3/8" bit in a post drill. When it makes the first 3-4mm hole it splits the block of wood. I have ruined a block of ebony and an expensive block of stabilised black palm. :censored:

http://www.uberlevel.com/link2image/dbf49h8g49.jpg

What should I do? Drill a pilot hole, or start off with a conventional 9mm HSS bit?

Help!

[MushiSushi]

use a lip and spur bit zed

[ZDP-189]

use a lip and spur bit zed

What's a lip and spur bit?

[ZDP-189]

http://www.axminster.co.uk/images/82m03.jpg

I see. But why is the block splitting and how is this different?

[Adi007]

I'm using this 3/8" bit in a post drill. When it makes the first 3-4mm hole it splits the block of wood. I have ruined a block of ebony and an expensive block of stabilised black palm. :censored:

http://www.uberlevel.com/link2image/dbf49h8g49.jpg

What should I do? Drill a pilot hole, or start off with a conventional 9mm HSS bit?

Help!
Generally it's the tips of those drills that are the problem because instead of clearing the wood away they screw themselves into the wood putting enormous pressure on it until - BANG! Split in the wood ... :mad:

Lip and spur gets around this because the point clears the wood away as it drills.

[MushiSushi]

what adi said ;)

[Gloria]

I use a metal drill bit for my drilling, I havent had a problem yet. I do drill pilot holes for the bigger bits. It works for me. :)

[stonehard]

I drill my scales in place ie stuck to the blade with double sided tape.
it aids in accuracy in lining everything up. so I use hss/tungstan metal drills and pilot every time

[narsil]

For smaller holes (up to about 10mm) I use conventional hss drills the same as I would use for metal and have not had any splitting problems except through my own mistakes. I usually try to rest the block I'm drilling on a piece of scrap wood and drill through into that which reduces the risk of chipping the far side of the hole. For particularly difficult woods like ebony I tend to drill a pilot hole first and then drill part way through from both sides. For larger holes or flat bottomed blind holes I tend to use forstner bits.

[Alick]

If you use a lip and spur like Mushi suggests (and these are good) don't forget - you DON'T drill a pilot hole first. :biggthump I'm pleased that Stonehard and others are getting good results from ordinary HSS jobber drills, but generally these tend to tear the edges when starting a hole in wood - that's what the lip and spur is designed to overcome (a new bit and harder woods will tear less though)

B&D / DeWalt are now doing a fancy hybrid tip on some of their pirhana branded drills, it's a metal cutting bit that sort of has spurs too to give a clean edge. For drilling through slabs and the blade together, this could be ideal.

BTW - As a newbie to the game, I just assumed that the easiest way was to drill the blade first to get the holes in the right place, then clamp the scales to the handle one at a time and drill down through the holes in the blade into the wood - then fasten the scales together for shaping and fix to the blade before final finishing. Is it better to drill through in one - I can see that it should give the best alignment, but might be harder to mark out accurately in the first place ?

Cheers, Alick

[stonehard]

you have opened a can of worms there Alick lets see what every one says

[PS_Bond]

B&D / DeWalt are now doing a fancy hybrid tip on some of their pirhana branded drills, it's a metal cutting bit that sort of has spurs too to give a clean edge. For drilling through slabs and the blade together, this could be ideal.


Saw those, then thought "how do I sharpen it?".



BTW - As a newbie to the game, I just assumed that the easiest way was to drill the blade first to get the holes in the right place, then clamp the scales to the handle one at a time and drill down through the holes in the blade into the wood - then fasten the scales together for shaping and fix to the blade before final finishing. Is it better to drill through in one - I can see that it should give the best alignment, but might be harder to mark out accurately in the first place ?


For full tang, I clamp & drill 1 side at a time; for hidden tang, I clamp the blade in a fixture, align the drill on the pin hole in the tang, then put the handle block on & drill all the way through.

I wouldn't be keen on drilling the tang at the same time as the slabs - a) the steel will be fairly hard (depending on what you did at HT) and b) the heat buildup will be high - possibly cracking the slabs.

[MushiSushi]

I wouldn't be keen on drilling the tang at the same time as the slabs - a) the steel will be fairly hard (depending on what you did at HT) and b) the heat buildup will be high - possibly cracking the slabs.

only M42 would do in such circumstances

[Colin KC]

BTW - As a newbie to the game, I just assumed that the easiest way was to drill the blade first to get the holes in the right place, then clamp the scales to the handle one at a time and drill down through the holes in the blade into the wood - then fasten the scales together for shaping and fix to the blade before final finishing. Is it better to drill through in one - I can see that it should give the best alignment, but might be harder to mark out accurately in the first place ?

as a beginner Alick, I'd start with parallel tang & parallel slabs, drill holes for tang, HT, clamp slab, drill through, mark the front & inside & hand of the slab, repeat for other hand. rough up a couple of pins & press them inna slabs (insides together, fronts at the same end) & finish the front, drift the pins.

'poxy 'n' pin one hand onna tang, allow to cure, do the same for the other hand.


voylah (as we people who speak french say;))

[MushiSushi]

And in english;

Drilling through in one, generally NOT good idea, first suggestion, good idea ;) drill hole prior to HT, even better idea, but M42 cobalt will drill through a hardened tang if necessary, but generally it isn't.

[narsil]

There are also a few safety points to bear in mind when drilling, especially drilling metal.

1) Drills, especialy cheap ones are quite prone to shattering without warning. The bits then turn into razor sharp missiles.

2)similarly a chuck key left in the chuck can do a lot of damage.

3) If the drill 'grabs' when your drilling the tang the blade will tend to spin round rather fast...not a good thing...best to clamp it very securely and keep body parts out of teh way.

This has all been said before but I think it bears repeating.

For best results you should also pay attention to the drill speed according to the size of the bit and the material. In general wood requires a higher speed than metal and larger diameter bits require a slower speed than smaller ones.

Marking the hole centers with a center punch is also a good idea especially if they need to be accurately positioned which they probably will. A bradawl will achieve the same effect in wood.

Driilling holes is actually quite a tricky business since it can all go pear shaped very quickly through one small mistake.

[Alick]

You're right there Chris - been there done every one of those ! Drill press and machine vice do help save your fingers :D

The web's not a bad source for recommended speeds and feeds for drilling different materials - it's not an exact science but
http://www.norsemandrill.com/Tech_Docs/feed_and_speed.html is quite good as they give target SFM (surface speed per minute) figures for various steels by Rockwell hardness instead of Brinnel. Then convert to get the optimum drill speed RPM=SFM ÷ 0.262 ÷ DRILL DIA

Mushi - I like cobalt drills too - except for the price - mind you a good masonry bit will chew through a file with no trouble at all - so if you do forget to drill before HT it's doable. Masonry bits don't leave a good edge but they're good enough as a pilot drill to save some wear and tear on your more accurate bits. A bit of cutting lube helps too.

Cheers, Alick

[Alick]

as a beginner Alick, ....voylah (as we people who speak french say;))

Colin - That works for me !

a la tienne mon pote :biggthump

Alick

[MushiSushi]

Mushi - I like cobalt drills too - except for the price - mind you a good masonry bit will chew through a file with no trouble at all - so if you do forget to drill before HT it's doable. Masonry bits don't leave a good edge but they're good enough as a pilot drill to save some wear and tear on your more accurate bits. A bit of cutting lube helps too.

Cheers, Alick

I did buy a set originally, but I've also got a comprehensive dormer set. From now on I just buy individual replacements from RS in the sizes I use most on steel and unless you're going big they aren't much more than a couple of quid each.

[narsil]

Its also possible to locally anneal a hardened tang by putting a plain rod in the drill press and applying it to the spot you want to drill with the drill running, the friction will generate enough heat at that spot to reduce the hardness of the steel. Not very elegant but useful if you do need to drill a hole in a hardened part for any reason. The heat will spread away from the hole to a certain extent but the oxide colours will allow you to keep an eye on that and cool the area if it starts to spread too far.

Of course if you use a differential hardening/tempering technique the tang wont be too hard to drill anyway.

[PS_Bond]

I forget.... Where's good to buy cobalt drill bits & saw blades?

[MushiSushi]

screwfix do sets of drills and also carbide jigsaw blades although they aren't in the online catalogue pt. no. D93612-74
Otherwise replacement drill bits are best bought through Cromwells or RS

[Alick]

Chris - didn't know that trick - nice one !

Alick

[acs1943]

This should open a new door
What about a wood router to drill the slab you can get some small 1/4" cutters.

I tend to drill the tang in the cut out and shape stage.
if you have tapered the tang you will get in to trouble because the slab will not be square to the tang if they are flat.
so how about just spoting the slab and then drill on a pillar drill square
if you drill before you taper the tang then the holes should be square.
But at the end of the day it will only be a nats out and you should use a clearance drill and epox will hide a multitude of sins.
believe me

alan
Still crazy after all these years

[ZDP-189]

I think I've discovered how to use that bit. I used it to bore a curly birch handle very quickly using an electric screwdriver. The bit gulps down wood at an incredible rate, but in a power drill it is obviously too much. I'll be shopping for tools in the UK when I get there.

[PS_Bond]

Bumping this one back up... Anyone got any useful suggestions on where to get Imperial sized lip & spur bits? My usual haunts of RS, Cromwell, Screwfix seem to have drawn a blank; Craft Supplies do them occasionally, but the price wasn't very good IIRC.

[stonehard]

Bumping this one back up... Anyone got any useful suggestions on where to get Imperial sized lip & spur bits? My usual haunts of RS, Cromwell, Screwfix seem to have drawn a blank; Craft Supplies do them occasionally, but the price wasn't very good IIRC.
try any american tool suppliers they still do it all in feet and inches.

[PS_Bond]

Yeah, I know... For 1's & 2's of drill bits, I'd prefer to find a UK supplier, however.

[Basemetal]

Costco -the Wholesaler - does lots of chinese manufactured budget multi kits of drill bits, dremel bits etc (<£20) -they seem to be originally for the US market and so are imperial sizes. I have a set that has lip and spur bits and the quality has been fine on light use. I don't have a feel for whether this is "good chinese" or "bad chinese" quality as I haven't resharpened anything yet.

[Lord Farquhar]

Draper drill bits are great for steel. They have a little pilot drill at the front of the tip to help the bit to not skid out of the hole. Also make sure when drilling steel that’s it clamped properly. When drilling metal, make sure you have a steel punch pin to give the drill bit a good start so it does not move. Be extra careful when the steel bit is going to come out of the underside of the steel you are drilling as this is the time it is most likely to bite and shatter so a vary control drill is best if you don’t have a drill press.

[MushiSushi]

Axminster do imperial

[PS_Bond]

So they do.... Not drilling down far enough! (er - no pun intended)

Boring bits/Wood boring bits/Lip & spur drill bit 3mm... And there are the Imperial ones too.
Of course, I'll have to make the order up to avoid shipping :rolleyes: