Major Problems CNC Extension

I had huge problems with this carve

I am thinking that the cnc extension shaft that I am using it flexing to much AND I need to go to the bigger .5" shaft one not the .25" I am currently using

I would like to see what you guys think

Feedrate: 80 inch/min
DOC: .080"
12,500 rpm

What size bit was that? I think you are going too deep for that little bit.

oh sorry that was a .125" mill

Onsrud carbide 2 flute downcut spiral

I have no problem cutting .125" DOC with that bit without the extension I have cut many things that way on my new machine

yeah thats what I was thinking the tool is just bouncing around

Man I really hate to do a .080" engraving in 500 step downs lol

The extension added a ton of runout, I am surprised the tool lasted as long as it did without breaking. Using an extension is never a good idea for a CNC router.

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that extension is supposed to be for the cnc

here is the link it is balanced for the spindle,0&keywords=TE-124

It sure looks like it would be better than a standard extension, but how did it work for you?


lol you got me there!!

but how else am I supposed to engrave inside of that box?

and really I think when I get the bigger 1/2" shank tool it will be alot more ridgid

Will your collet accept a 1/2 inch shank? If it does then that will make a world of difference. But you may still run into trouble with the the long shank acting like a lever on the bottom of the Z axis and moving it all over the place.

You may need to take the sides off the box first.

Yeah with my spindle I can go .125, .25, .375, and .5 end mills

and yeah I was just really avoiding to take the side off that is just alot more work

(these are production items so anything that you can do to save time

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As a rule, always use the shortest tools you can, for rigidity. If you have to stick the tool out like that, you HAVE to take smaller depth cuts, slow down, and check for runout at the tool tip.

Very true but in this special case I need to use a extension I can take shallow depths of cut I just wish there was a more rigid tool out there

I ordered the .5" shank tool this morning so I hope that it works out alot better

I have a CNC Router Parts PRO4896 machine now with a Bosch 1617 Router Soon to be 3hp water cooled spindle with vfd

Bosch will except up to 1/2" shank tools

I use precise bits precision collets

If you do not have some of these tool, Treat yourself and order them now. I have the same Bosch 1616 and these 1/2 inch tools are the best cutters I have ever found. They leave a perfect bottom in your pockets and can make the smoothest profile cuts you have ever seen. At $6 each it feels like stealing them.


Yeah I mainly use Onsrud tools that is a killer deal for 5 onsrud mills why are they so cheap?

a single 40-024 lists for 24.90 through my local distributor

you ordered some of these?

I can’t find them in the Onsrud catalog?

no 40-024 only 40-023 and 40-025 and those are upcut

the only downcut listed in the catalog for the 40-000 series is 40-008 and 40-012

I ordered them a few months ago and received them in a week, They are the real deal, I thought it was just someone that did not know what they were selling, but the seller keeps listing them as fast as they are bought. So I have no idea how he sells them so cheap.

But they are the real deal, brand new still covered in the factory dip plastic. Be careful pulling the plastic off the tools are crazy sharp.

I may order 5 more just to have a life time supply. I have been using one for about 50 hours of cutting in plywood and it is still as sharp as when I opened it.

I tried looking them up also and could not find them either, but they are really downcut tools just like the description says.

Yeah Onsru tools are ligit I have a bunch of them I might have to look into this listing and get some thanks

I just looked at my ebay history, I actually offered him $25 for the 5 and he accepted that price :slight_smile: