Reply with QuoteBrass is grabby stuff. Would it be possible to drill about 1 1/8 inch then finish with your cutter? Maybe pilot drill and follow on with a larger drill? Negative rake inserts might help also.
You might take a look at this Youtube video.
Help needed for deep pocket
I have been milling 1 1/4” diameter by 2 3/4” deep holes in brass.
So far I have been using Tormacks 17mm center cut 2-insert end mill on a medium length end mill. I’ve been running my 1100 at 54 ipm, .05” doc with a spiral center plunge at 4300 rpm. I got this from gwizard.
This worked well for the first 20 holes but then out of the blue the em grabbed the brass and twisted the head off. I did change to fresh inserts after the first 10 holes so maybe it was ready for fresh inserts.
I’m now thinking of changing my approach.
Any good ideas out there?
I’m currently thinking I might pre-drill the holes with a 1/2” drill then use another 17mm insert em or possibly an abs tools shear-hog (the one that screws to the medium length arbor so I can get down to 2 3/4” deep.
I could 1/2” pre-drill then try an extended length 4-flute 1/2” em (4”?) and see if that works over having to keep buying new insert em’s.
Thanks in advance for any thoughts.
Similar Threads:
Re: Help needed for deep pocket
Brass is grabby stuff. Would it be possible to drill about 1 1/8 inch then finish with your cutter? Maybe pilot drill and follow on with a larger drill? Negative rake inserts might help also.
You might take a look at this Youtube video.
Jim Dawson
Sandy, Oregon, USA
Re: Help needed for deep pocket
Originally Posted by Jim Dawson
Works well on plastics, and sheetmetal, good for anything thats thin and prone to grabbing when exiting the work.
mike sr
Thanks for the video link. I wonder if it would dull a large drill bit (1/2” to 1”) too much.
I like the idea of just drilling large holes but the most expensive have drilled on the 1100 is 5/8” and it always feels stressful drilling large diameter.
Has anyone drilled 1”+ on a Tormach?
I guess if I ramp the pilot drills up in 1/8” to 1/4” increments it might be ok.
Truthfully I was hoping to do one drill op an one hogging/roughing op to get the time below 7 minutes.
Re: Help needed for deep pocket
I do 3" deep holes , 6 " in diameter with in 6061 wit a shear hog. I spiral down the center first and punch through the bottom. This leave a path for the chips get out on the following operations. Lots of flood cooling and the chips flow out of the center hole nicely.
Hi Austin,
Very cool. Which shear-hog are you using to get that deep?
My parts are 6” deep and I don’t use coolant with brass so I have to blow the chips out as I go. Pia
Don't know how it would work on brass, but
Im using the sh787-6 directly in the tts collet.
Thanks Austin. That one should do it. How did you modify the shank to fit in the tts collet? Did you bevel the end and put a tts ring on it?
I have an atc so it would be great to use it with the atc.
FYI according to nyccnc the shear hogs work great in all non Ferris metals.
Never mind my previous post, I see that the er32 collets go up to 3/4” so I will use that.
Thanks again!
Re: Help needed for deep pocket
Look at the cutter in the middle of the image. I use a 3/4" clamp collar from Mcmaster car. I can slide it up or down to adjust tool stick out. The collar stops against the face of the spindle just like a TTS holder. These type of machines are not very rigid, so you want to keep the stick out to an absolute minimum. The sorter the gauge height, the better.
Look at the cutter in the middle of the image. I use a 3/4" clamp collar from Mcmaster car. I can slide it up or down to adjust tool stick out. The collar stops against the face of the spindle just like a TTS holder. These type of machines are not very rigid, so you want to keep the stick out to an absolute minimum. The sorter the gauge height, the better.
Brilliant idea. Thanks for the photo.
I will most likely not be using the shear-hog with my atc so that should work. I find that when I am roughing I need to really crank down the PDB so that precludes using the atc.
BTW, I was looking at shear-hog bits yesterday and it sounds like their radiused inserts (.03 to .06) will last longer than the ones that have the sharp tip.
I’m going to get a few to try.
Also AB tools said that they recommend the single insert shearhogs for drilling as well as hogging as opposed to their multi inserts tools which have to drill/ramp much slower.
AB said their shearhogs work well with all non-ferris metals.
I still can’t believe 6 cu in a min.
AB recommended drilling down at 5 in. A min. Then hogging at 90 in. A min. At 5100 rpm
Can’t wait to try it
Thanks again
Re: Help needed for deep pocket
I made TTS collars for the long tools I use on my 1100.
I hade them out of 6061 aluminum and I made the 3/4 inch center hole
.003 to .004 smaller than the shaft it’s going on. I’ll heat the aluminum collar, slide it on to where I want it then give it a shot of cold water. With .003 to .004 if press fit, there’s no way you’re going to move it when you change tools.
You can buy GOOD PARTS or you can buy CHEAP PARTS, but you can't buy GOOD CHEAP PARTS.
Great idea Steve
QUOTE=Steve Seebold;2210210]I made TTS collars for the long tools I use on my 1100.
I hade them out of 6061 aluminum and I made the 3/4 inch center hole
.003 to .004 smaller than the shaft it’s going on. I’ll heat the aluminum collar, slide it on to where I want it then give it a shot of cold water. With .003 to .004 if press fit, there’s no way you’re going to move it when you change tools.[/QUOTE]
Re: Help needed for deep pocket
It will do the 6 cubes, but with my stick out it was horrifically loud and vibrated the the whole machine too much for comfort, so I backed it down to 4 cu in. It will certainly drill, but without HP through spindle coolant, clearing the huge chips is difficult even with massive flood cooling. You don;t have to drill too deep before the crunching chip/interference sound starts. The tool on the right in my photo (Maritool 1/2" ZRN serrated rougher) is my favorite tool for roughing < 1.5" deep. No drama ,and it humms through aluminum at 5 cubes.
Thanks for the insights and feedback, Austin.
I love the Maritool corncob rougher. I wish it came in longer lengths.
I have been having to manually blow the chips out on these pockets since I don’t use coolant on brass. I’m hopping for a one-tool solution and hoping the shear hog will evacuate lots of chips.
If I end up putting a tts ring on the shearhog, I may rough with the corncob first then switch to the shearhog.
QUOTE=AUSTINMACHINING;2210392]It will do the 6 cubes, but with my stick out it was horrifically loud and vibrated the the whole machine too much for comfort, so I backed it down to 4 cu in. It will certainly drill, but without HP through spindle coolant, clearing the huge chips is difficult even with massive flood cooling. You don;t have to drill too deep before the crunching chip/interference sound starts. The tool on the right in my photo (Maritool 1/2" ZRN serrated rougher) is my favorite tool for roughing < 1.5" deep. No drama ,and it humms through aluminum at 5 cubes.[/QUOTE]
Re: Help needed for deep pocket
[/QUOTE]
Good luck CadRhino, Let us know how it works out. I'm, curios how the SH will work in brass,
Good luck CadRhino, Let us know how it works out. I'm, curios how the SH will work in brass,[/QUOTE]
Will do. Right now I’m deciding in the insert. I’m leaning towards the altin coated .03” radius inserts.
Will do another brass run soon
