It always happens!!

[Blogwitch]

Over the last few weeks, I have designed and been making a very hi speed drilling unit. I need to drill holes of 0.006" diameter or less for making gas jets for miniature bunsen burners to use with flame licker and sterling engines.

http://www.jerry-howell.com/Propane.html

This is as far I have got, maybe 3 or 4 hours work to completion. It will run at about 50K RPM.
It is made out of a donated DTI stand and a couple of cheapo bits from China, plus of course some bits 'n bobs from the scrap box. It will run from the air system in my shop.

About a year ago I mentioned to a friend that I was on the lookout for a cheap hi speed PCB drill.
Last night, he turned up and gave me this, FOC.
A purpose made Meddings hi speed drill. This one is only equipped with the cones to go up to 6K RPM, but it is a dead easy job to make new flat belt cones (they can be bought, but are rather expensive) to get way past that figure, and the blue blank you see, when turned up, should get me up to around 12K, once I get some larger ali blanks, I expect to be up around the 20K mark.

I had to try it out, and I'm sorry for the fuzzy pic, the termite holes are 0.020", shown against a 3mm cap screw.
No problems drilling these at 4.5K RPM.

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[ksouers]

John,
That's a nice score! Price is right, too!
Those little itty bitty teeny tiny holes look more like pin pricks. How do you feel your way through a hole? There can't be any kind of feedback to know how the hole is progressing, is there?


Have any plans for the "dentist's drill" now?

 

[bentprop]

Well done,that man ;D
What concerns me most,how do you see where to drill the hole?????
I have enough trouble lining up a 1/16th drill!
I wish I had friends like that.Come to think of it,I wish I had friends :big:
Another dumb question,John.The drill you fabricated runs on air,you say.How does the air pressure get converted into the rotary motion of the drill?Is there a turbine blade or something similar hidden inside the shaft?
Enquiring minds want to know.

 

[SBWHART]

I prefer your home made one John its not as heavy .


Rof} Rof} Rof}

Have fun

Stew

 

[Blogwitch]

You are quite right Kevin, there is no feedback at all when using really tiny drills. So a very fine screw feed is really the way to go, just so that you can't put too much pressure on while taking the cut. But the Meddings has such a smooth action, and a superfine rack feed, that it is very easy to SEE how the drill is progressing.

The final tiny drills I will be using only have a penetration depth of about 0.100" (2.5mm) anyway, so deep drilling won't be possible with those ones. I will only need to drill about 0.040" (1mm) deep anyway. But they do need to be finely spot drilled first, even tiny drills at high speed will wander and break if given the chance.

For spot drills in the UK, I have found these to be about the cheapest, and they do last a very long time.

http://www.engineeringsupplies.co.uk/advanced_search_result.php?keywords=spot drill&sort=2a&page=3

I use the 90 deg ones for most of my small work.

The one I have made can easily be converted to be used as a drill spindle on the lathe. I only need to mount a square bar onto the side of the spindle carrier, and it can be held in the toolpost, or I might even turn it into a high speed spindle for my miller, I just need to offset the air drive to the side. I have loads of very small milling cutters that need a bit of speed to keep them rigid and stop them breaking so easily, and also be able to use it with the RT and DRO for very small precision drilling work. So it definitely won't go to waste. Getting the time to do it all is the problem.

And just to answer Bentprops questions.

My eyes aren't that good either any more, so for making a few items, I will make up a little fixture to hold the part, so that it can just be dropped and locked into the correct position every time, but for freehand stuff, I will get out my magnifying headband or my desktop magnifier.

The pinky/purply bit is a mini die grinder. I just made a little drive fitting to go between it and the once to be used as a flexi drive handset.


With regards to friends, and gifts from them. I prefer to give things away if I have no further use for them, as visitors to my shop find out, or do jobs for nothing rather than asking for payment.

Sometimes, people will remember you for your kind actions, and you will find that things like this just happen out of the blue, without even asking for it.

Second hand, this Meddings drill is worth the cost of a new mini lathe. So I must have impressed my friend a little.

I forgot to mention, Stew came down this morning to lift it onto my bench for me. Thank you Stew.


John

 

[Seanol]

John,
Good things happen to good people.

Congrats,
Sean

 

[dsquire]

John

What Sean said is exactly what I want to say. I'll also add that what goes around, comes around. Now I've got to get some new glasses to see if your drilling holes or pulling my leg?

Cheers

Don

 

[ieezitin]

Hi guys.

Nice work John as usual from you.

Seeing things small is getting to me now as well, I am 47 and been wearing glasses for about 3 years I find them a PITA.

I too bore small holes often, not as small as this but I tend to hit the high number drills a lot, so I got myself a Machine Bore scope. Great tool it magnifies so fine that you can see grain on some metals, it makes a center pop mark look as big as a pizza!.

Plus it fits most collets and all chucks.

All he best. Anthony.

 

[BigBore]

Cool toy, Blogs. I like it and the design also. I used to repair dental hand pieces in Germany for about a year. The air turbines in them could spin them at 100's K RPM. The best way to quality control the repair was to run them in a small sound chamber since anything out of tolerance would result in noise or weird harmonics. I assume this tool is some sort of a turbine also?

Ed

 

[Blogwitch]

Anthony,

Unfortunately, a centre pop mark would just be too rough for the size of drills I will be using, and it would just snap them off. That is the reason for the spot drill and locating jig. I have just fitted a mag chuck onto the larger of the two drills. So I will drop the jig on the mag chuck, locate the jig with a pin from the drill chuck and turn the magnets on. If I am lucky, everything will be in line and I can just drop the pre spotted jets into position for drilling.
All pie in the sky at the moment, but in theory, it should work. I will know a little better in a couple of weeks when the tiny brass bolts for the jets and the drills arrive from the US.

Ed,

I was looking at the dental drills, and they certainly can get up there. There are a couple of problems though, most have their own special fitting for the bits, and would have to be drastically modified to hold the drills, and the price, enough said on the price. But one good thing about them, if the turbine gives up, it is just an easy swapover job, and you can even get different speed range turbines. The faster you go, the more expensive they get.

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