Very Small Nuts

[mikemill]

How do you make small flanges and then have four holding nuts 0.050"AF without going mad with tweesers.
Cheat by milling the whole thing out of solid, when its on the model you will never know!! Pin heads are rearly quite big.

Mike

[neilw20]

Keep the magnifying glass in your pocket.!! Shhh...

[mikemill]

Neil
I guess you are not a model maker, and therefore would not appreciate the efforts people go to recreating the world in miniature.

[harryn]

Mike, I think Neil understood just fine. His comment was that you keep the magnifying glasses in your pocket, was as in- keep them handy ! He was impressed with your work.

So am I.

Your mill must have some really good control on it.

Harry

[neilw20]

Hi Mike

The smallest drill I use is 0.2mm and I make my own 0.3mm endmills from 0.3mm broken drills and can do the same with the 0.2mm drills too.

Not trying to compete, but a might make a small one like yours one day, just for fun. I make my own miniature connector pins.

My modified SX3 machine will repeat to 0.002 in Z all day!! On stainless.
Like for 2000 hours now.

The X,Y springiness in the ballscrews and gibs were giving me some grief, till I purchased a small surface grinder and used teflon lube on the slides.

Thanks for the heads up harry.

Neil

[HorridHenry]

What do you do with the tweezers?

When I need to put very small nuts on a securing point,I stick the nut on a piece of double side carpet tape then screw it on till It time to use a spanner....works everytime

[mikemill]

Neil
Apologies if I misunderstood your comment, as you use small cutters please advise me on speed and feed
The flange in my post was cut with a 1mm three flute tool at 0.020” deep X 1” per minute feed and suds, I made three flanges and the tool broke!!
The material is compo brass; I think the problem is the cutter is choking with swarf, any ideas?
My machine is a SyilX3 running Mach and no modification

Mike

[neilw20]

Main problem with SX3 is column stability when Z moving up and down.
I have the gibs very firmly adjusted and the top of the column is braced to a brick wall because the base allows it to flex too much.
For Good Z control, move Z down too far and go back up a bit to cancel the head nod.
Mine is 35 microns now.

When possible do all machining at the same Z level once the height is set.
It also takes nearly 1 hour for the spindle to settle with temperature.
About another 35 microns expansion there.

Leave it running flat out for an hour before attempting precision work.
The X and Y gibs I grind on a surface grinder every 50 hours or so.
Without being really tight and true it will not end up where you ask it to but approaching from the same direction all the time will give repeatable results.

As for cutting settings, depth of cut maybe 10-20% of cutter diameter.
All small work can be done at full spindle speed.

How fast to feed? Examine the chips under a microscope to figure out what is good.
For only 3600 RPM 1"/min is way too much cutter load, (IMHO) and you are are at 50% cutter diameter. Cutter strength is the limiting factor on small cutters. On brass cutters much top rake will dig in.
Never let the cutter eat it's own rubbish. Disaster there.
FLOOD coolant. If you are not making a mess and can watch the job, you will kill the cutter.

For good cutter strength I use very short cutter to minimize flex.
Small bits must run very true to work well. A little runout on a 3 or 4mm cutter might not be noticed.
Keep it down to under 1% of cutter diameter.

Feedrate? Examine the chips under a microscope. If the chips are irregular so will be the cutter life.

Cutter flex is not conducive to even chip size so if more than about 3-4:1 length to diameter, you need to reduce the feed rate down to maybe 0.3"/min or thereabouts.

Turn on CV. I see you have some marks where the cutter has been dwelling. Exact stop can make lots of marks.

Always climb mill. If you are using backlash compensation, fix the backlash. The compensation will mess up nice small work.

Hope this helps.
I often grind single flute cutters out of broken drills. Original design of wishbone sharpener from handlewanker (Ian)

Neil

[Joe S.]

I agree with nearly everything Neil posted or have no opinion due to lack of expertise (mine). As for cutting depth, I try to error on the much lighter cut side and make up the time in the feed rates. to that end I usually go no deeper than 1/4 diameter when milling full cutter width and prefer to go even lighter than that. My theory is cutter flex is a fact of life, and the shallow cuts make smaller steps in the cut leading to a better finish, remember we're talking small cutters here.
Compute the rpm and feed rates according to standards and adjust as the machine and material allows (usually slower) . Even tiny little cutters can chatter because the machine or collet holder or the moon is feeling a bit sloppy . . . Carbide cutters flex less, live longer at RPM and . . oh yeah cost more. . . . Oh yeah, I almost forgot, use the cutter appropriate to the material, esp. as to number of flutes, composition (material), and helix.

[aarggh]

That's a lot of great info there Neil! I'll be checking out that drill jig of Handlewanker too now as I haven't found an easy way to resharpen those minute drills yet, and I've got a box full of em!

cheers,
Ian

[txcncman]

Every time I read the subject of this thread I can't help but laugh out loud.

[ArtsyFartsy]

Did anybody see that video about the Chinese Farmer who developed his own wind-powered car? I think it only goes up to about 30mph, but that's still something to go off of for more stuff.
I tried posting the video, but apparently new users aren't allowed to post links or anything. Search for it on youtube under, "wind-powered car". It should come up as the third or fourth video, he's in a light blue car that looks really box-like.