03-01-2016, 07:22 AM
I've been asked by a friend to make a die body for him out of 4140, which will be heat treated. The external dimension will be 7/8" diameter and about 3.5" in length. A .311" hole will need to be bored approximately 2.5" deep.
I have two questions:
1. How much distortion would you expect in the 4140 and would a wire cage and liquid soap in the bore reduce this and/or scale formation? I've used the wire/soap with good effect on threads in O1
2. Most places I have looked (quick search) list .311" reamers as .3115 U/S, which I assume to mean under size. They define D/P as being dowel pin but don't specify U/S or O/S. My metric reamers only specify 5mm, 6mm etc. I have some tollerance on the + size but the bore cannot be less than .311"
One option I have is to drill and ream, and then if the hole comes out undersize after heat treating, is to mount the Dremel and find a stone with a long shaft and put together a poor man's tool post grinder.
I think I am going to make a D-bit reamer, as I contacted a local tool supplier today and was quoted $110 for a .311" reamer, as they have to be custom made. Enco wants less than $20 for a US one but postage and time are limiting factors. Especially since the Australian dollar has taken a dive...
Thoughts, suggestions and comments welcome.
I have two questions:
1. How much distortion would you expect in the 4140 and would a wire cage and liquid soap in the bore reduce this and/or scale formation? I've used the wire/soap with good effect on threads in O1
2. Most places I have looked (quick search) list .311" reamers as .3115 U/S, which I assume to mean under size. They define D/P as being dowel pin but don't specify U/S or O/S. My metric reamers only specify 5mm, 6mm etc. I have some tollerance on the + size but the bore cannot be less than .311"
One option I have is to drill and ream, and then if the hole comes out undersize after heat treating, is to mount the Dremel and find a stone with a long shaft and put together a poor man's tool post grinder.
I think I am going to make a D-bit reamer, as I contacted a local tool supplier today and was quoted $110 for a .311" reamer, as they have to be custom made. Enco wants less than $20 for a US one but postage and time are limiting factors. Especially since the Australian dollar has taken a dive...
Thoughts, suggestions and comments welcome.
Hunting American dentists since 2015.