Thread: Starter bits

I'm planning to buy my collets from CTCtools but I guess there all from the same supplier in china, CTC also sell seperate collets so I was going to buy a few key sizes on top of a set.

ER11 COLLET SET (13 PCS) #A02


Not too sure about the router bits as I havnt done alot cnc routing but the straight 2-flute carbide tipped cutters did a great job when I used them on wood (2D stuff), for perspex homann designs sells them, they look like standard 2 flute endmills but maybe the cutting angle is a little higher than normal like the aluminium endmills.

Originally Posted by Ch4iS

I'm planning to buy my collets from CTCtools but I guess there all from the same supplier in china, CTC also sell seperate collets so I was going to buy a few key sizes on top of a set.

ER11 COLLET SET (13 PCS) #A02.

Hmm, 2 extra collets the, smaller ones I assume. Looks like it might be a better deal, depending on their postage cost. Will have to check it out tomorrow.

Russell.

Precise bits have the best range of small cnc cutters that I have come across. They are also available from soigeneris.com and he has cheaper postage. Cheers Paul.

Originally Posted by BoomerangInfo

Hmm, 2 extra collets the, smaller ones I assume. Looks like it might be a better deal, depending on their postage cost. Will have to check it out tomorrow.

Russell.

I plan to do alot of aluminium so I got a 2nd 6mm collet, probably wont need it but if for some reason it breaks I have a replacement there ready to go.

Also got a bunch of 3mm and 6mm endmills from CTC, those aluminium cutting endmills are expensive (compared to the 4 flute ones) ~$10 USD for a 3-flute 6mm cutter, 4-flute are $1.50 each

Hmm maybe I'm asking the wrong question.

How does on learn which bits are good for what? There's a lot of posts saying "what bit do you use for this" in other forums, but not much info on actually figuring out the meaning of how all the factors relate. I've started reading the Mach3 manual, and it's very "comprehensive" but quite confusing.

Guess I just keep googling and piece things together, one bit at a time

Russell.

Hi Russell,
I have been using a CNC machine for six years and still learning what to use.
It would require pages to document what cutter to use and then there is feed, speed and depth of cut. Most of the latter is dependant on your spindle horsepower and speed and the rigidity of your machine.
And then you have conventional and climb cutting.
No easy answer and why you are not being flooded with responses.

To get you started get some solid carbide two flute upcut cutters as these are fairly universal and will cut MDF through to ally. Also get some 60 degree V bits for engraving and the two cutters will cover 90 percent or more of your work.

Feed, speed and depth of cut experiement with. Use your eyes and ears when you are cutting and you can tell when it is cutting on song as I call it. Some good advice I was given is if the chips are coming off in the shape of a letter "C" then you have the correct feed and speed. This of course is the shape of the flute in a spiral flute cutter so you have optimum cutting if you get this.

G'day Russel,

I have wasted a fair bit of money on overpriced and unsuitable bits and now have a short list of useful ones. Keep in mind I only have 1/8" and 1/4" collets. Solid carbide is the way to go as they last well and will take a fair bit of punishment, (some of my clamps still bear the scars and I'm still cutting with the bit) but they are brittle and will break if dropped on the concrete.
I use a few ball noses in 1/8" and 1/4" mainly for 3D carving in timber. 2 flute cut nice but I also have a 6 flute 1/4"for harder timber and Ally.
End mills in both 1/8" and 1/4" same flute arrangements as ball nose except the 1/8" is single flute and believe me they break easily. 4mm would be a better option if you have the collet. I also have a 19mm square sided carbide tipped router bit out of a standard set that I use for surface milling timber and roughing pockets in large pieces. These larger bits are not designed for plunging cuts so be sure to add ramps to tool paths if possible to ease the cutter in to depth.
V-bits 90deg 1/2" carbide tipped and 60deg 1/4" solid carbide for all engraving, lettering, V-carving.
As Rod mentioned set feed rates conservatively in tool paths and tune up by ear.
Some software has feedrates and pass depths built into tool tables. Do not ever assume these are correct for your machine, only treat them as as a rough guide if that.
As for prices others know better than me, as I said I've wasted lots of money.

Cheers,

Tim.

I have found that carbide bits are absolutely useless when you don't turn on the spindle. if you just drive them into the workpiece and then start moving the x and y axis they snap off quick as anything. In this regard, they don't last any longer than HSS and the results they give are pretty similar, but the carbide costs a lot more than the HSS.

Bob Willson

Originally Posted by Bob Willson

I have found that carbide bits are absolutely useless when you don't turn on the spindle. if you just drive them into the workpiece and then start moving the x and y axis they snap off quick as anything. In this regard, they don't last any longer than HSS and the results they give are pretty similar, but the carbide costs a lot more than the HSS.

Bob Willson

Yep did that, slow learner I am, I had 4 single flute 1/16 bits I was using for cutting little polycarb plates, I broke 3 and the 4th one cut me over 2000 pieces so it paid for itself and the others, can't wait for my little spiral bits to show up.

Thanks for the tips guys. It's all starting to make more sense now. I also fond a manufactures site that has quite a few tech notes as well, which is helping.

So apart from the couple of suppliers mentiones already, does anyone have any other recommendations for where to shop, or are those mentioned the best bang for buck?

Russell

Hi Russell,

Try Whiteside for V groove router bits (1540 &1541) - a tip from one of Rod's posts Good quality and price with reasonable shipping too.
For ballnose and square end mills you could try carbidework on ebay.

Cheers,
Woodlake

Originally Posted by Bob Willson

I have found that carbide bits are absolutely useless when you don't turn on the spindle. if you just drive them into the workpiece and then start moving the x and y axis they snap off quick as anything. In this regard, they don't last any longer than HSS and the results they give are pretty similar, but the carbide costs a lot more than the HSS.

Bob Willson

Ha ha...looks like we could start a club with those of us that have done that, personally I was doing some servo tuning and ran a test g-code that I thought was going to be an air pass but forgot to set the Z axis, so it was NOT an air pass...more like a stab the most expensive bit you have into the table and snap it like a twig pass, arg !

But back on topic, as Rod mentioned a couple of V bits and some good straight bits will do a lot of what you will need at first, there are some nice bits for cutting ply, but I personally haven't used them, but I hear they are quite clean cutting. For trial runs the cheapies are good but once you have things sorted the more expensive bits do last a lot better in my opinion...unless you run into clamps, table etc, then the result is almost always the same, and a little depressing

Cheers.

Russell.

Well I've just finished up my full-time job, and started my part-time one. My machine has been posted from China, and my Aspire DVD arrived in the post. So now it's time to start finalising the bits & pieces, so I'll take the info from here and do some online shopping over the weekend and see what I come up with.

Russell.

Russell

The rounding on the end of a ballnose bit is most often expressed as a radius.

So a 6mm dia ballnose will have a 3mm radius. 3mm dia will have a 1.5mm radius etc.

I think I am pretty average and I use 1/4", 1/8" and 1/16" ballnose bits to cover 99% of my 3D carving. (6mm, 3mm and 1.5mm approx)

If you have a set of metric collets then go with metric shank sizes. (preferable but not essential)

Greg