Milling - What am I doing wrong

The chips look very small to me. You may need to increase the feed rate to do more cutting and less rubbing.

Do you have a spindle lock? If not then trying to tighten the R8 collets tight enough to hold the cutter with enough force may be a problem.

Martin

I think you've identified the problem P1H - sorry used to horizontals (where the knee doesn't tend to move too much on it's own - and is sometimes hard to move when I went it too!)

If this is a new tool - then it should be fine. Even a sharp tool is subject to very high forces, so if your quill moves that easily - then the tool will most likely cut properly once it's held to the work (so to speak).

Regards,

IanT

Off oot doon the toon for a ruby.

Will answere questions tomorrow and take photo of close up photo of the end of the cutter. I also have a coupld of general milling question if you don't mind

One other thing I noticed from your pictures is the mill (in one picture) is in high speed. Most of my milling is done in the low speed setting except when I use small mill cutters

Petrol head, If I were making tee nuts as you illustrate, I would start the "Perfect" side from the opposite end so feeding from right to left so the feed is going in the opposite direction than the cutter is trying to drag the work, and then tackle the opposite side in the reverse direction from left to right. Having the collet and quill locked up is essential too.

Chris Gunn

Ah crossed posts! I suspected a loose quill.

If you have knocked off the sharp points of your end-mill don't despair, a quick and dirty fix from Tubal Cain is to relieve the corners to make a small facet at a 45 degree angle with a bit of relief*. You can't cut into a square corner and leave a sharp angle, but fine for most jobs (and a tiny fillet in a corner is often a good thing as it eliminates a stress riser).

Neil

*I've never had to resort to this...

Your width of cut looks too wide. You should have no more than 1 tooth cutting at once, which more or less means the cut width should be less than 1/4 of cutter diameter. Half a millimeter depth of cut is very small, and is concentrating all the cutting on the corners of the end mill. To echo Martin Connelly, if your feed rate is too slow the cutter wil rub and go blunt very quickly. Aim for 0.004" per tooth per rev.

As a newcomer you would do well to buy a copy of either Arnold Throp or Harold Hall's books, they cost about the same as a coupe of cutters and will save you lots of blunt ones

**LINK**

**LINK**

As you like a picture here are a couple of videos I did for another query, you can see the sort of feed rate I'm using, cutter is not as good as the Arc ones but leaves virtually no burr and makes decent size chips not iron filings. Slightly less powerful X3 mill

6mm wide cut, 16mm dia cutter 2mm deep EN3 steel, 750rpm

This time 2mm deep and a bit slower at 500rpm

Edited By JasonB on 03/03/2017 20:46:03

Edited By JasonB on 03/03/2017 20:48:17

After 50 years of Bridgeport operation with R8 collets I know it takes a while to get the feel of how tight to tighten the cutter. Best to strip a draw bar thread than have a cutter pull down into the table. If I have any concerns of this happening I use a Clarkson chuck.

I see petrolhead is using a cutter with a side slot in the shank. I have ER32 and have always wondered if that type are OK used in a straight collet, or is the collet's grip weakened by the slot? .

Dave

Jason were both Test Cut 1 and 2 at 2mm?

Any views on this book - **LINK**

A good rule of thumb to work with is the full diameter of the cutter in width and half the diametar in depth or half the diameter of the cutter in width and the full diameter in depth. That'll give a reasonable load for an HSS cutter. or pro-rata!

In general, try to use as much depth as possible, since that's using more of the cutting edges on the flutes. the more use you get out of the sides of the cutter, the more metal you can remove with it before the corners go blunt and you have to get a new one.

Carbide can be worked harder.

Edited By Mark Rand on 04/03/2017 00:42:28

Yes, if you look at the DRO after the first cut it was adjusted from 2mm to 4mm for the next cut and then at the end of the only cut in second video it is at 6mm. There is also a third video 19mm high and taking off 0.6mm

What diameter was teh cutter you were using?

Edited By JasonB on 04/03/2017 08:03:18

I don't have that book- but I believe it relates more about what machine and accessories to buy, whereas '35 Milling a Complete Course' **LINK** is excellent about techniques and skills, although primarily with a series of useful projects to make...

Harold Hall's website has a list of the contents of this book.

**LINK**

You can see if it suits your needs.

Martin

I was using a 14mm cutter.  Cutting 7mm wise which is the same width as one edge on the cutter

Bought Harold Halls book

Edited By petro1head on 04/03/2017 09:33:00

I removed the tool and took a couple of photos. oh dear its fooooked

So so far I have learned that I need to lock the quill etc. I must only take a max of one flute width off. I need to feed into the direction of the rotating tool. This however leads me to a question, on the job I was doing the bottom was correct, feeding into direction of rotation but how would you do the top?

I needed to machine down a total of 12mm, should I be taking heaver cuts, ie 2mm each time (Jason?)

I am going to need a new 14mm cutter, should I buy another HSS from ARC or a carbide cutter?

Edited By petro1head on 04/03/2017 09:47:07

In the first picture on this thread, the cutter is not square to the work, perhaps a swivelling head is rotating due to the feed forces,

I think its just a bad photo. Everthing was setup before use, but will check just in case, thanks

Edit: Just check and its ok

Edited By petro1head on 04/03/2017 10:16:42