View Full Version : Cutting end mills

Dick Plasencia
10-05-2005, 12:18 PM
I have several one inch double ended mills. What is a good way to cut these in two to make two single ended mills? I made an adapter to use them in my mill/drill but They stick out a long ways.


10-05-2005, 12:41 PM
You could use a thin kerf CBN metal cutting blade used to cut metorites. This place has 6" x .012" for $38.00


Your Old Dog
10-05-2005, 12:50 PM
Give'em to me for a few minutes. I've had pretty good luck snapping'em in half http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

10-05-2005, 12:54 PM
Assuming the mills are HSS. Do you have or have access to a surface grinder? Any shops nearby? A surface grinder and a thin C/O wheel will get it done. Feasable? Unless you can DIY, depending upon what they will charge you to have it done.

In the home shop, abrasive wheel. Like you would use on a chop saw. If you have a chop saw, taking your time, you could rig up something to hold the mills to cut them. Not sure how safely it could be done on one though. The problem (other than holding the mills) would be the heat generated, unless you can keep them cool, you might burn the temper right out of them.

Water jet, laser, and EDM will cut them also. Probably cost prohibitive though.

[This message has been edited by ERBenoit (edited 10-05-2005).]

10-05-2005, 02:52 PM
use a cut off tool.. from HF for $19 www.harborfreight.com (http://www.harborfreight.com) ITEM 47077-0VGA Just like the automobile exaust shops use.

10-05-2005, 03:52 PM
Cheap abrasive cutoff blade. Heat wont be an issue. JRouche

10-05-2005, 08:35 PM
tool post mounted Dremel.

10-05-2005, 09:54 PM
I made a mandrel for a sewing machine motor to moun cheap fiber reinforced cut off wheels. The wheels were 3 inches in diameter and 1/32 thick. I think I got them from ENCO. You have to stop and dunk the work in water once in awhile. Takes about 7 min. for a one inch endmill

10-06-2005, 12:10 AM
<font face="Verdana, Arial" size="2">Originally posted by ERBenoit:

The problem (other than holding the mills) would be the heat generated, unless you can keep them cool, you might burn the temper right out of them. </font>

That's not a problem if they're HSS, and they likely are. High speed steel is most difficult to anneal-----it requires excessive heat, and a slow cool in a furnace.

The typical method for parting such items is with a cutter grinder and a parting wheel. If the item in question lends itself to spinning, it can be parted, literally, in seconds. I've cut off large (greater than 1") 6 flute taps that required a regrind on the end. The cut off operation took less than 15 seconds. The cut is so fast that the heated area is only about 1/8" beyond the cut-----and being HSS, made no difference. Quenching the tap or end mill after cutting could change all that, though. It should either be done wet, or dry, and allowed to air cool. Any quenching risks thermal cracking.


[This message has been edited by Harold_V (edited 10-06-2005).]

10-06-2005, 08:49 AM
<font face="Verdana, Arial" size="2"> The problem (other than holding the mills) would be the heat generated, unless you can keep them cool, you might burn the temper right out of them.</font>

My bad. I figured trying to lop off a 1" dia. mill without cooling, would generate enough heat to ruin the mill.


Dick Plasencia
10-06-2005, 10:22 AM
Thank you all for the excellent suggestions. The reason I have a few of these large double ended mills is they were only $1.00 each. That was hard to turn down. So a solution to cutting in half also has to be cheap. From every reply I came up with with a combination that I think works for me. I'll install a thin abrasive cut off wheel on my tool post grinder. Chuck the mill on the lathe and cut away. That's after everything is covered to protect the lathe from the grinder dust. If this works and I have no doubt they will be real cheap mills! The only issue I see is how long will it take to cut one in half.
Thanks again!!


[This message has been edited by Dick Plasencia (edited 10-06-2005).]

[This message has been edited by Dick Plasencia (edited 10-06-2005).]

John Lawson
10-07-2005, 12:55 PM
Where is a good place to get meteorites?

10-07-2005, 01:03 PM
Wire EDM

10-07-2005, 01:29 PM
"Where is a good place to get meteorites?"

The Antarctic.

10-08-2005, 09:23 AM
This is the setup I used to do 3/4" endmills.

I tilted the "turkey roaster" and used a small aquariam pump to cool the part with water with some baking soda in it. Also, had to put up a backstop to keep the spray confined.

Both the angle grinder and "converter" are from Horrible Freight.

10-08-2005, 04:54 PM
Use a chop saw. Buy it - I have a Makita, cost about $95.00. You are cutting the shank, not the actual cutting edges. Will not hurt the cutting action.