Drilling small holes

[firebird]

Hi

I needed to drill some very small holes for jets in a meths burner ( see my post A SMALL BOILER for more info ) I bought some small drills ranging in size from 0.4mm to 1.0mm to play with but the 10mm chuck on my X1 mill is a bit cumbersome for these small drills and the maximum rpm of 2000 isn't fast enough. The following is what I came up with. I have a Dremmel type mini drill that I bought some time ago from B & Q for £20.00. Its 12 volt, runs off a seperate power supply and has a variable speed of 0-20,000. I made a jig to hold it which in turn is held in a 1/2" collet in the X3 mill. The jig itself is made from a piece of ally angle with a 1/2" piece of ally screwed onto one end with 5mm countersunk screws and a 1" piece of ally screwed to the other end with a piece of 1/2" ally round bar pressed in. The mill is unplugged from the mains and has a hose clip with some card board packing fitted to prevent the quill from turning. It works a treat. I haven't included any dimensions as it all depends on what type of mini drill you have.

Drill out the 1/2" ally.

Then bore out to accept the mini drill.

Do the same to the top piece and screw them both to the ally angle.

All the parts.

Hose clip round the quill.

The power supply.

Fitted into a 1/2" collet in the mill.

Heres a short video. Its a bit dark but you will get the idea.

[ame]http://www.youtube.com/watch?v=q2Cs6zsTNVE[/ame]

Any questions just ask

Cheers

Rich

 

[Bogstandard]

Richard, very nice.

I will be building one very similar to it soon.

I need around 20K rpm minimum for drilling 0.01mm (0.004") holes.
I think in theory it should be around 90K, but I will settle for 20K, and take it very steady.

Well done on your 'fix'

John

 

[BobWarfield]

Very nice!

FWIW, if you don't yet own a Dremel, I've heard Proxons have lower TIR. So do Bosch routers if you want a little more power and think you'll ever want an engraving head.

Cheers,

BW

 

[Mcgyver]

Rich, very smart of you to unplug, else you know what you'd by rote!

getting spindle speed will help and make the job go faster but the real challenge for very small drills is less spindle speed than sensitivity. here's some ideas to help in that regard, the counter balance table makes it very easy to feel the action of even the smallest drills. with a high speed spindle and sensitive table you're away to the races

http://www.homemodelenginemachinist.com/index.php?topic=1445.0

your dremel may be ok, but check the run out. They are notorious and if run out is too much it'll bust drills.

 

[CallMeAL]

This is great, I too may have to make something like it.

 

[Circlip]

And someone always has to jump in over safety, Power supply cooling slots Rich? ? Yes I know It's staged. Otherwise great.
Regards Ian

 

[John S]

I did one similar a while ago on an X 3 but mounted the Kress spindle above the X3 to get more room.

This machine has an ER 32 collet system direct into the spindle nose so it doesn't require a drawbar, this leaves the spindle free for a drive shaft to go thru to the top mounted Kress.

The bottom of the remote spindle has two 10mm x 19mm bearings that are held in a normal ER collet and the end is machined to a JT0 taper to take the small ER 11 collet chuck.
Variable speed on the Kress gets you from 12,000 to 43,000 no load speed.

Very handy for engraving.

.

 

[firebird]

Hi Ian,

Thanks for spotting that. I'll cover it wiith something or move it out the way. Good thing about this forum, plenty of solid advice.

Cheers

Rich

 

[Circlip]

I know you staged it REALLY :big: but just as an aside, Self adhesive Velcro pads make superb "Sky hooks" (Providing you're not trying to suspend your miller on them) Regards Ian.

 

[Nick Hulme]

Nice one, if you want rigidity for milling you could do it this way too

http://i135.photobucket.com/albums/q158/magicniner/DSC00775.jpg

Regards,
Nick

 

[firebird]

Hi Nick

My method does not leave a lot of room between drill and table. Mounting it like yours would increase it. How did you fix the mounting to the mill?

Cheers

Rich

 

[macona]

Tormach sells the Proxxon as a high speed spindle attachment for their machine. A guy in the local model engineering group built a small cnc mill using one as the spindle. It is supposed to run a lot smoother than a dremel.

One of the attempts at a high speed spindle was one of the Precise PowerQuill Spindles. I got one off ebay but the darn thing is huge. Rated 45k RPM at 1HP! But the collets are over $200 each. I found though that I can make collets from ER-16 collets on my tool grinder. Finally used it the other week to true up the jaws in my chucks.

I got axed last may so this summer I took on some work for a stop motion animation movie studio and made some money off the tools in my garage. One of the projects involved drilling a few thousand holes in some aluminum project boxes and milling openings for connectors and the like. It would have taken forever at 6k rpm. Just in the nick of time a Nikken Highspinner popped up on ebay that matched my machine taper. I think I paid $300 for it. New cost is something like $3000. It increases the spindle speed by 5 times for a max speed of 20k rpm. Its supposed to have less than a micron runout at 4x tool diameter. Really worked nice. Paid for itself in one job.

 

[Nick Hulme]

Hi Nick

My method does not leave a lot of room between drill and table. Mounting it like yours would increase it. How did you fix the mounting to the mill?

Cheers

Rich

Rich,
I bored a hole in the block to accept the quill, slotted & installed clamping bolts. Stick the quill out far enough, lock it & clamp the block on, I then pull the block firmly against the underside of the head with the quill & lock it.
I'm lucky in that my Y travel allows use of the full bed this way & that influenced the design, you could mount it with the auxuilliary tool at the side or use a fixture plate to extend the table if Y travel were a problem,
Regards,
Nick

 

[Andrewinpopayan]

A couple of years ago I bought a "knockoff" Dremel pattern tool from "Aldi" supermarket for £19.95. It's direct mains powered, variable speed and it came with a host of pretty useless tools, but it did come with some collets and a flexi-drive.

I haven't had a problem with mine and would recomend that you keep your eyes open for them in Aldi and Lydl stores. (UK)