Author Topic: Drill bits Unlimited and the drill press  (Read 1168 times)

Offline GazzaS

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Drill bits Unlimited and the drill press
« on: May 08, 2018, 03:02:13 PM »
HI everyone,
    In one build I've managed to snap three .35mm bits despite trying to be careful.  I seem to have a problem with any bit under .5mm.

Is there a setup for us modellers and styrene in the shape of a drill press?  I was just preparing to pin some ailerons and I was wondering if there was a setup gentle on model parts which will keep me from breaking bits...  as often.

I don't just want to go buying something because an advert says it's so.

Thanks for your thoughts,

Gaz
There are only two states to be in:  Queensland and blotto.

Offline RLWP

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Re: Drill bits Unlimited and the drill press
« Reply #1 on: May 08, 2018, 05:57:59 PM »
My thoughts - don't use a drill press!

Making small holes in plastic models I use a pin chuck: https://www.ebay.co.uk/itm/Pin-Chuck-Set-3-Collets-0mm-to-2-5mm-Drill-Bits-Suit-Lathe-Vice-Drills-M0250/352104293004?epid=1767844551&hash=item51fb0d228c:g:Vu4AAOSwYmZXK0tg

Not powered either, just rotated using my fingers

Don't leave too much drill stuck out the chuck, it bends and breaks

I often make larger holes from small ones using taper reamers, I have some quite small ones

Using very small drills under power is always going to lead to breakages - maybe you have to accept that?

Richard

Offline GazzaS

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Re: Drill bits Unlimited and the drill press
« Reply #2 on: May 08, 2018, 06:32:54 PM »
Richard,
    Thank you for the insight.  I was using a pin vice.  The only power was me. 

Gaz
There are only two states to be in:  Queensland and blotto.

Online lcarroll

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Re: Drill bits Unlimited and the drill press
« Reply #3 on: May 08, 2018, 10:20:52 PM »
Breaking micro drills is inevitable
     Funny, I've been thinking about this problem for a few days now. I go through them at a horrific rate despite following all the cautions listed by Justin and Richard here. I 've reverted to not using any type of holder or pin vice in an effort to reduce side loads on the bit, they just will not tolerate any such forces and not being very careful with keeping the swarf cleaned off results in the same high breakage rate.
    Dremel makes a mini drill press for some of their models, has anyone tried that method? Seems to me reducing the potential for side loads on the bit should offer some improvement , or not?? I don't really mind having to purchase replacement bits however leaving half a bit shank in the hole causes no amount of grief on my little production line!! >:( :(
Cheers,
Lance

Online krow113

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Re: Drill bits Unlimited and the drill press
« Reply #4 on: May 09, 2018, 02:32:45 AM »
Stabilization is key to the longevity of drill bits.
Power drilling is problematic , the bit catches and its over.
Not many Dremels or other small hand drilling machines go slow enough for the work.
UMM makes a smaller chuck that can be put in a pin vice or held by hand:
http://umm-usa.com/onlinestore/product_info.php?cPath=21_161&products_id=3338
As with all of their stuff its very well made and versatile.

I also have modified small wood handle pin vice, cutting down the wood handle:

This may be a better holder as it has less weight than a pin vice , the weight of the holder alone being enough to easily break the drill bit.
Don't be afraid to modify or make your own tools , if it works then that helps the problem solving.

As for technique ; the 'bite' of the bit , that is to say when it has cut into the material , has enough tension to break the bits. This is where I think your problem may be Gaz. I would suggest the smallest rotation in the cutting direction , no more than half a turn , then reverse rotation with the tiniest pull out , this will minimise the chip and cut it off with less tension. I set up a back and forth motion with my fingers , practise this with your fingers , try to keep the motion even and slow , back and forth. Also I will pull the drill in an outward direction as I rotate in the cutting direction , this minimises the cut.Stabilize the parts , the drill and holder and yourself as well.
Takes some skill and practise , but that's the essence of modelling.

 And taking into consideration that it is unadvisaeble to say ANYTHING bad on the internet , I will state here that purchasing cheap pin vices from ebay or otherwise can be counter productive. I bought a set from a UK SUPPLIER  and found them to be very very poor in quality. The drill will chuck up ok but upon examination the quadrants that recieve and hold the bit are machined inexpertly , therefore the drill is OFF-CENTER .
Watch out for this and buy from machine shop supply or model tool suppliers.
« Last Edit: May 09, 2018, 03:49:20 AM by krow113 »

Offline IvotB

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Re: Drill bits Unlimited and the drill press
« Reply #5 on: May 09, 2018, 04:52:53 AM »
Somehow you can understand why Drill bits unlimited are selling their drills in large quantities: yes we all break them. However there are a number of ways to avoid this as much as possible although I will need a new set of 50 pieces of 0,4mm soon :)

First of all the question is in what material you want to drill a hole. If it is plastic perhaps a HSS version or HM version is better than the carbide drill, because they are a little bit more forgiving.

In principle drilling by hand is asking for problems. I use pin vices and 12V print drilling machines. Most pin vices do not hold drills smaller than 0,5mm very well. The drilling machine can be controlled better, but it depends on how you can switch it on and off and hoe you can control its speed. Usually I'm missing at least one hand to do this proporly. Recently I tried to use my Dremel with a flexible axle, but I was very disappointed by its speed control (lowest position too fast) and that if your holding your model in one hand and the drill in the other I can't find a way to switch it on and off. That's when I suddenly realised that I might use the pedal of a sewing machine for the purpose of switching it on and off and to control the speed. And this works very well! When I explained it on another forum I soon got youtube videos and other videos showing that I didn't invent anything new.

Have a look here:

http://hackedgadgets.com/2007/04/01/dremel-foot-pedal-mod/comment-page-1/


There is another more elaborate work around that really doesn't break any drill and that is to use it for instance in a Proxxon milling machine like the MF70.

Here you have full control. You can fix your model to the machine and move the drill around to the desired position etc. But is more time consuming than the Dremel with sewing machine control  :)

Just as an example:

Drilling holes in 0,6mm brass tube for spark plug leads in a Mercedes D.III





Or scratching lamination lines on propellors:



You used to be able to see these images in a thread of mine here about building an LVA Fokker D.VII, but Photobucket spoiled the fun. Although with the add-on showed here on the forum you will be able to see those images.


regards,
Ivo

Offline Berman

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Re: Drill bits Unlimited and the drill press
« Reply #6 on: May 09, 2018, 06:41:46 AM »
The problem with electric drills is that they cannot be made to operate slow enough to simulate hand drilling. A DC motor at low voltage loses too much torque. An AC motor will overheat operating at continuous low RPMs through a controller. Harbor Freight stocks a pneumatic micro grinder at a low price. This can run at very low speeds or high speeds or any desired RPM, by simply regulating air pressure and volume, without losing torque. The tool is lightweight and there are collets to accept various size drill bits. It costs $30 USD but 20% off coupons are always available.
« Last Edit: May 09, 2018, 11:41:21 AM by Berman »

Offline RLWP

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Re: Drill bits Unlimited and the drill press
« Reply #7 on: May 09, 2018, 07:04:54 AM »
If you do some research, for really small drills most hobby kit doesn't run fast enough. Not that hobbyists use drills like industry does

Here's my selection of drilling tools:



The two middle pin chucks are 'proper' ones. One is an Eclipse, I'm not sure of the make of the other. I think the shanks have been turned down by a previous owner

The whopper at the top is a rather nice CAV chuck of an ancient 'Wolf' electric drill (deceased) which I use by hand. I guess I should fit a nice knob to the thread

The small one I suspect is one of those described by krow113. The jaws are badly cut and probably not central. Even so, it's handy if used between the fingers and it does hold very small drills. I wouldn't like to use it under power

Finally, on the left is a selection of taper reamers

I have lots (and lots (and lots)) of other drills up 2" diameter, not so relevant to this task

Richard

Offline GazzaS

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Re: Drill bits Unlimited and the drill press
« Reply #8 on: May 09, 2018, 04:35:13 PM »
Guys,
   Thanks for your helpful replies.  The pin vice I use is just like the one Red Baron showed.  The rest of your tips will come in useful, but I'm a bit relieved to see that I'm not the only one going through the bits. 

I prefer to buy a bunch of bits in a size instead of some variety pack.  That was nice about UBL.  But it is really hard to find stuff under .5mm

Gaz
There are only two states to be in:  Queensland and blotto.

Offline GazzaS

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Re: Drill bits Unlimited and the drill press
« Reply #9 on: May 09, 2018, 06:26:00 PM »
That's another excellent one!
There are only two states to be in:  Queensland and blotto.

Offline Ryan

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Re: Drill bits Unlimited and the drill press
« Reply #10 on: May 10, 2018, 12:27:29 AM »
I've broken a few in plastic...gouging them out and repairing is great fun!

Ryan

Offline petrov27

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Re: Drill bits Unlimited and the drill press
« Reply #11 on: May 10, 2018, 06:16:53 AM »
wow really wish I could drill brass tube like Ivo does there above - that is awesome but I don't think I can talk myself into buying the Proxxon.....

Offline aliluke

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Re: Drill bits Unlimited and the drill press
« Reply #12 on: May 17, 2018, 09:35:19 AM »
I use a pin vice and don't have very many breakages even with 0.25 mm drill bits. I think Red Baron has the right answer - make a pilot hole with a # 11 blade tip or a sharpened needle in a blade holder. Work upwards from a small bit to a larger bit to get to the hole size you want. Brace your arms with your elbows. Drill straight and slow. Clean the plastic "furls" off the tip frequently - these clog the tip and can cause sideways pressure. The breakages I have are usually caused by bumping the bit sideways accidently.

Pilot holes - the way to go in my opinion.

Alistair
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Offline wmoran

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Re: Drill bits Unlimited and the drill press
« Reply #13 on: May 17, 2018, 01:50:14 PM »
Also, if you're drilling the holes for the control wires through the fuselage, drill the holes BEFORE you close up the fuselage (I learned this the hard way).  There is usually a little bit of the broken bit sticking out on the inside of the fuselage, allowing you to grasp it with some needle nose pliers and carefully pull it straight out.  Pfalz aircraft are particular tough to drill these holes because you have to drill at an angle, which makes it so much easier to break the bit.  If you can't get to the inside of the hole to remove a broken bit, you can try using the last bit of a broken bit that doesn't have flutes in it to push the bit the rest of the way through the hole.  This only works if you had already drilled completely through the plastic before breaking the bit. 

Bill

Offline Borsos

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Re: Drill bits Unlimited and the drill press
« Reply #14 on: May 17, 2018, 02:57:07 PM »
HI everyone,
    In one build I've managed to snap three .35mm bits despite trying to be careful.  I seem to have a problem with any bit under .5mm.
Three? You snapped three? I do have a mass grave of killed drill bits under 0.5 mm behind my house hidden under the trees -- but don't tell it to anybody!
Borsos
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