Sparks Fly

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macardoso

H-M Supporter - Silver Member
H-M Supporter - Silver Member
Joined
Mar 26, 2018
Messages
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Was using my G0704 CNC to part off some 1/2" stock to make a fixture. I'm not in the bandsaw owners club yet. Anyways do this all the time. 3/8" endmill, 5000rpm, full depth slot, 20ipm and let it rip. Anyways this time I get an inch into the material and get a big chatter squeak. Start reversing out of the cut and sparks start flying everywhere.

Turns out my TTS straight shank tool holder pulled out about 1/8" when the chatter happened and I was already running danger close with the vise jaw. Hardened ER collet nut hit the hardened vise jaw. The tool holder won.

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So yeah I feel stupid, especially since I just finished scraping this vise. This must be the first scratch on a new car kind of deal.
 
Sad to see this after all that work. Slipping TTS is a bummer. Is it really that sensitive, or just needed more torque?
 
jwmelvin said:
Sad to see this after all that work. Slipping TTS is a bummer. Is it really that sensitive, or just needed more torque?
Click to expand...

Not too much of a biggie. I can get a new set of master jaws for $25 I think from Shars. Might hit the corner with a light chamfer and call it a day.

I've not had much issue with the TTS system on my mill. Others have had bigger issues. I've found that if I get chatter, the tool is coming out no matter how hard I have it clamped. I do not often get chatter.

My system is designed to clamp at around 1800lbs tension on the drawbar. Considered adding another air stage for 33% more holding force and changing the belleville washers up to be a bit stronger.
 
macardoso said:
Was using my G0704 CNC to part off some 1/2" stock to make a fixture. I'm not in the bandsaw owners club yet. Anyways do this all the time. 3/8" endmill, 5000rpm, full depth slot, 20ipm and let it rip. Anyways this time I get an inch into the material and get a big chatter squeak. Start reversing out of the cut and sparks start flying everywhere.

Turns out my TTS straight shank tool holder pulled out about 1/8" when the chatter happened and I was already running danger close with the vise jaw. Hardened ER collet nut hit the hardened vise jaw. The tool holder won.

View attachment 363120

View attachment 363121

So yeah I feel stupid, especially since I just finished scraping this vise. This must be the first scratch on a new car kind of deal.
Click to expand...
Hey, it's bound to happen. Don't feel bad.
Yesterday I was using my lathe, auto feed, all of a sudden I hear a knock, knock, knock. I slammed down on the emergency stop.
The chuck had an interference fit with the compound. The last time this happened I was a sophomore in High School.
Yeah, I feel stupid.
It happens.
 
The damage to the jaw isn't bad. I'd probably just stone it flat in all 3 dimensions and call it a day. It is incredibly rare that I use the 'corner' of my vice-jaw for anything like indicating or indexing, so I would bet you'd be the same way.

That said, perhaps a nice time to consider making soft jaws :)
 
I guess something is going around (besides the virus) I snapped the tip of my Xacto knife cleaning swarf out of a hole in 6061 I was boring while the part was turning. Got caught between the boring bar. Left a nice chop mark on the edge of the hole, but I was able to smooth it out mostly. Dumb. Won't do that again.
-Mark
 
ErichKeane said:
The damage to the jaw isn't bad. I'd probably just stone it flat in all 3 dimensions and call it a day. It is incredibly rare that I use the 'corner' of my vice-jaw for anything like indicating or indexing, so I would bet you'd be the same way.

That said, perhaps a nice time to consider making soft jaws :)
Click to expand...
I've got 2 or 3 pairs of aluminum soft jaws I've made for various uses. I do tend to use these the most though.

I might clean it with a carbide chamfer mill so it looks nicer, stone the burr, and call it a day. I don't mind using my tools and this is bound to happen.
 
markba633csi said:
I guess something is going around (besides the virus) I snapped the tip of my Xacto knife cleaning swarf out of a hole in 6061 I was boring while the part was turning. Got caught between the boring bar. Left a nice chop mark on the edge of the hole, but I was able to smooth it out mostly. Dumb. Won't do that again.
-Mark
Click to expand...
Yikes! Xacto blades and moving machinery sound like a scary combination!
 
I have a G0704 cnc conversion and had the pull out on mine, only mine came completely out, so I built a Power Draw Bar with about 3800 lbs of force draw bar pull and have never had it happen again. Used a 30:1 EnerPac air/hydrolic intensifier B3006 @65 psi. I must admit I shamefully got the idea from here
http://linuxcnc-g0704.blogspot.com/2014/09/hydraulic-power-drawbar.html. I changed up some of the design like I used a one piece top hat and a 1/2” 4140 hardened draw bar. Plus i increased the thickness of all cross peices that get full pull weight, by .125 to 7/8“ steel. I needed as much room as I could get because I’m running a 2hp 3ph motor, so I did order an used, the od theaded 2 inch cyl. It works great.
CH
 
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