[yoopertool]

The company I work at has some parts which have deep hole drilling. The hole diameters vary between .371"-.451" and can be between 7-10" deep. The material is 316SS. We have been making these parts for a while now with a gundrill as the pilot and a long reamer for the finish. I would like to eliminate the reaming step and simply gun-drill to size while maintaining a 32Ra max finish.

The part is being drilled on our large horizontal mill using a highly concentrated water based coolant (high pressure through spindle). We use that mill alot and arent willing to convert to oil based coolant.

Does anyone have any suggestions on gundrilling through 316 and maintaining the finish requirements (which is what we struggle with right now)? Any help would be appreciated. Thanks

Joel

[RICHARD ZASTROW]

There are gun reamers available that would do the job. The Mapal and Cogsdill reamers and many gundrill tools use a carbide pad to burnish the holes.

You might also consider roller burnishing tools from Cogsdill (or ???) instead of reaming.

Dick Z

[beege]

The company I work at has some parts which have deep hole drilling. The hole diameters vary between .371"-.451" and can be between 7-10" deep. The material is 316SS. We have been making these parts for a while now with a gundrill as the pilot and a long reamer for the finish. I would like to eliminate the reaming step and simply gun-drill to size while maintaining a 32Ra max finish.

The part is being drilled on our large horizontal mill using a highly concentrated water based coolant (high pressure through spindle). We use that mill alot and arent willing to convert to oil based coolant.

Does anyone have any suggestions on gundrilling through 316 and maintaining the finish requirements (which is what we struggle with right now)? Any help would be appreciated. Thanks

Joel

I'd talk to someone at eldorado about your application. I had to get an 16 finish in some stainless, and their recommendations left me with about a 10 consistently. Had to do with the speed, feed and especially the pressure of the coolant at the cutting edge.

[yoopertool]

Eldorado has been supplying us with gundrills for a while now. The only problem is that we can only get about 7-8 parts out per drill before it needs to be sent out for sharpening (we dont sharpen our own drills). With the quantity of parts we make we would have to be changing drills out constantly and purchase multiple times more just to keep them in rotation.

I had been looking at gun-reamers, but with no prior experience with them was a bit timid to investing so much money into an unknow product (to me). Has anyone here had much experience with gun reamers? I would like some input on these if I could as far as finish, tool life, etc. Thanks for the help!

Joel

[Liberty02]

We used to make thousands of 0.25" holes to 5" depth and we used 10 inches per minute and close to 5000 rpms. Our machine is also El Dorado and the drills used to last for hundreds of holes.

Our machine has 2 spindles taht are independent (you can run 2 parts at the same time) and we are having problems with one of them, I think the problem is the commuter on the motor that may be jumping electricity and that causes either the drills to bend or break on the tip, you may need to check if your feed is constant or it may be variying and your rpms are constant.

I hope this helps you a little.