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Hi, i have recently recived some center drill bits as recomended by another member, i know what they are and how to use them.
I was just wondering if anyone had any advice or Tip when using them, i have been using them to make nema 23 motor mounts for my cnc machine:
http://www.mycncuk.com/forums/photop...1_DSC05057.JPG
Sorry kip i hit the wrong button, kips posts are below:
Quote:
Be careful when using small ones on hardened steel...they break!
And use a scriber rather than a marker pen as it's better for accuracy and never rely on a piece of metal being "square" when marking out.... :D
Yes it did take me a few go's to get the holes right, i managed to get the holes close enuff that i could then file out a small amount so my screws would line up with the motors.
Now i have a template i just use that to make/mark out new plates and so on:
http://www.mycncuk.com/forums/photop...1_DSC05172.JPG
There are some really naff centre drills around, regular PITA when they snap off. I got some cheap, centred 2 holes then lobbed the lot straight in the bin.
Caveat emptor, I've gone back to Plan A, don't use anything but Dormer :D
Thanks kip i didnt think of that, i'v downloaded the file ill take a look soon !Quote:
Originally Posted by Kip
Quote:
Originally Posted by Robin Hewitt
I got mine from ebay, dont think they cost much more then £10. I take my time with them and they seem to be ok, now i think just a small drill bit would have more then likly done the trick anyway :)
CM
You really need CNC it makes it so easy and everything lines up just perfect. No more swapping centre drill then bit then countersink/bore on every hole :DQuote:
Originally Posted by CheekieMonkies
I draw everything with AutoCad, convert the milling to G code and overlay the .dxf file on the cut file. Then I can use the "Move to hole" feature which puts me on the hole nearest the mouse.
:) now i can mount my motors, my machine can move/work, guess what i will e making with my machine once its up and running :D
First thing I made when I got my mill CNC'd was a suds pump :DQuote:
Originally Posted by CheekieMonkies
Yea i was thinking i'm gonna need to keep things cool if i'm doing ali cuts ? i was thinking of having a vac to clear the "chips" and my compressor blowing to keep the cutter cool ?Quote:
Originally Posted by Robin Hewitt
Have you got any pics of your pump?, this cnc stuff is leading me into so many "new area's" of making things so on, i love it i wish i had tuned in at school and gone down this path for a career.
Cheers,
Lee
I have the working drawing if that's any good, the pump is up at my shop.Quote:
Originally Posted by CheekieMonkies
That's a 40mm impeller, (I just happenned to have some 40mm diam polyurethane)
I drive it with a DC motor through a variable voltage regulator, that way I get to adjust the flow using a pot on the front of the machine. Works good :D
Would be nice to see some pics if you get a chance Robin, will defo come back to this at some point.
FWIW, a picture :D
Now that looks KOOL !
Maybe that's why it's called koolant? :DQuote:
Originally Posted by CheekieMonkies
Hi Robin,Quote:
Originally Posted by Robin Hewitt
Can you share some more info on this process?
Cheers.
It's home brewed software that pumps Gcode out to the parallel port as steps.Quote:
Originally Posted by Hogout
It is a bit simple minded when it comes to arcs and you have to boot DOS so it has full control of the timer interrupt, but you are welcome to a copy if insane enough :beer:
Robin
Forget centre drills, they are a throwback to earlier days and were designed for putting in the support holes for centres on lathes, hence the name.
No commercial CNC shop would dream of using centre drills today, instead using what are called NC spotting drills.
These are very stiff short fluted drills that will start a hole off without wander and not break like the flimsy centre drills.
Nearly the same results can be obtained using a good quality stub drill.
John S.
Quote:
Originally Posted by John S
And avoid "UK Drills" on ebay.
I bought £30 worth of cheap Jobbers bits, the first two I tried broke almost instantaneously, the rest followed them quickly in to the bin :rolleyes:
Hi Kip
My Z axis is delayed. First I'm remaking my standoffs for the milling table. The previous set was too clever, interchangeable bolt holes in different sizes. I soon lost precision.
This time I'm making 20 in 5 different threads, all cut from the same 3/4" thick steel bar and all 3/4" thick :beer:
Robin
John,Quote:
Originally Posted by John S
I have looked at the webpages of the usual suspects but none mention 'spotting drills' only centre drills. Do you have a source?
Cheers.
About the cheapest spot drills in the UK I have found are here. Put a search in for all diameters and go to the bottom of the second page then the third.
http://www.engineeringsupplies.co.uk...11=192&12=&13=
They are very good quality, both the Cobalt and Carbide, and if not really abused, should last almost forever. For £20 to £30 you can kit yourself out with a decent range of sizes and angles up to 8mm, over that, as in all places, they get expensive.
I tend to use the 120 degree ones, as that almost matches the standard grind of a normal twist drill of 118 degs. For holes that have a countersink requirement, I use the larger 90 degree ones to do the countersink first, then drill down with a normal drill from that, two ops in one.
Hope this helps
Bogs
Dormer aren't what they used to be...I picked up a set of drills, made in Mexico of all places. Drilled a hole in a piece of 1/4" mild steel and managed to snap a brand new 10mm drill bit straight in half with just the torque from a cordless drill and in a hand tightened QR chuck too!Quote:
Originally Posted by Robin Hewitt
That's the first time I've ever managed to break a drill over about 4mm in diameter!
Complete carp!