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Tips/Techniques Carbide insert chamfering tool for AXA

Tips/Techniques
Ya, it wasn't quite like I was picturing either lol. I was envisioning more of a bent neck tool at 45* initially, but guess I drew it more as a large chunk of HSS with a section cut out. Either way would work, all you need to do is present a suitable cutting edge to the material. The foundation of all machine work really.

I just revised the picture a bit....
chamfer toolbit.png
 
I just revised the picture a bit....

That doesnt work as well with a tangent grind for rounded chamfers. So I'll stick with something closer to your first sketch.

To be honest, I'm not really a fan of 45 degree chamfers. Too often they just double the number of edges that need a chamfer. A tangent grind eliminates that problem.
 
I agree, somewhat. I see the merit, and like the tangent grind look. Both have their place. Some parts call for an easy on the eyes, more rounded edge break, and others for a crisp 45* corner. When I file an edge break, it's generally with a rounding motion, I like curves. Never hurts to have many options, and keep ones feet free of being cemented in place.......
 
and keep ones feet free of being cemented in place.......

Ah yes....... Could be why I'm so "set" in my ways....... LOL!

Just for shits n giggles, help me remember when a 45 chamfer is actually better? I'm drawing a total blank. But that could be just another example of why old guys should retire.
 
"Better" is subjective. Some people prefer sharp defined corners, some parts look better with them also. Chamfers and deburring is actually one of those things that instantly jumps out on a machined part for me. The uniformity, or the lack thereof stick out like a sore thumb. There are times when I look at a part and think it looks like shit because the machinist used a Noga tool instead of programming a chamfer tool and it doesn't fit the rest of the part, or why is that chamfer 0.015" and that one over there 0.02"?. In general, I don't really care either way, I'm firmly waaaaay more on the practical side vs the OCD side of machinists, but that's not to say I still don't actually notice the little details like that. It's tough to turn off. At the end of the day, do what ever you wish, however you want. Unless the print calls for it, then do it like that :D.

Story time (for shits and giggles).....at my last job I designed and built these "hinge drops" (think precision hinges) for our fixtures. We could buy them and often did, but I came up with a better design that was more versatile in a few ways that we could shop make much more accurately and a bit more cost competitively vs buying them. The were also scalable so I could easily make one offs bigger or smaller if needed. I made the machining fixtures, soft jaws, and programmed them incorperating 0.025" chamfers with a 90* tool, or directly into the 2d toolpaths in every op so when they came off the machine, there was no deburring and zero hand finishing required. Just blow them off and paper wrap them in a box to go straight to anodize. We (I) made hundreds in small batches over the years.

Fast forward about 7-8 years, a couple new customers wanted a different locking design. Ours used a captive thumbscrew, they wanted a 1/4 turn knob. Cheap labour has trouble with righty tighty/lefty loosy i guess....So I had to redesign the model, and redo everything to make the new method work. I was now too involved with other stuff to do it, so another programmer/machinist took on the task of actually making them after I finished the design. He didn't see value in programming the chamfers in the machine because it was too hard, and the cycle time was too long, and he preferred to do it offline in between cycles with a noga tool, router and files.....Same parts essentially function wise but IMO they looked like complete dogshit compared to the old ones with chamfers/edgebreaks all mismatched for size, and zero uniformity, vs the crisp clean sharp edges from a tool. Cycle time wise he was about the same overall per part sure (new design took a bit longer), but the original point of making them in house was also to do batches in between busy times, simply to keep the spindles running, and guys busy working during slow times. I'd set them up to run with 4 vises on the table, one for each OP, so that every button press (~23 minutes) two finished parts came off, and it didn't really matter if the machine sat idle for 5-10 minutes after running before I got back to it to shuffle parts down the line. He did the ops in batches, and deburred after each cycle. Tied him up the entire run, while I was able to design/program other stuff while I was also making parts. Two different methods, very different results. Didn't matter one bit for the end use, it's just tooling so who really cares? Subjective.....

IMO this is one of those grey areas you can't really teach. Sure you can make a callout on every drawing specifying 0.025" 45* chamfers on ALL edges (and be THAT engineer.....), or simply a note about breaking them. Everybody is going to see and do it differently and have varying levels of "good enough" for whatever pleases their eyes. Uniformity is easier to achieve with a 45* tool, as it's the same no matter how you present it to an edge. I've never had a PM reject a part or tool buyoff for lack of uniformity of the edge breaks, but I have had them comment that it looks like shit......It matters a hell of a lot more on cosmetic consumer grade parts. We had great machinists that you could absolutely NOT give those types of parts to, not that we did a lot of that, but sometimes. I have a couple good stories about those too, but another time lol.

Anyway, long rant (and a lot of shits and giggles) to basically say, you either notice the details, or you don't, then from there you either care about them or you don't. To each his own. I almost always notice them, but I don't always care if that makes sense. Depends on the part and situation.. Across the same part, I'd prefer them to at least be uniform comparatively. Noga tools create more rounded corners with unequal legs kinda like your tangent tool, so if you're going to use one, at least use it on ALL the edges and make them the same. Don't router some edges with a chamfer tool, others with a noga, and then jab a file at others you can't reach with the former two. I'm a fan of all of them for various reasons depending on part geometry and end use.
 
Just for shits n giggles, help me remember when a 45 chamfer is actually better? I'm drawing a total blank.
Chamfers and deburring is actually one of those things that instantly jumps out on a machined part for me. The uniformity, or the lack thereof stick out like a sore thumb.

Silly me. I figured you thought it was necessary or better in some way, but I never once considered consistency. I only make one-offs so consistency for volume parts doesn't matter and never crosses my mind. One offs is prolly another reason I like tangent chamfers.

Thanks for taking so much time for a very thorough explanation. It all makes a lot of sense Dan.
 
I decided to give this a try.....

Prolly gunna take a lot of grinding to get that tool to clear the work so it can do its job. Left clearance, right clearance, nose clearance, etc. etc. I think the limiting factor will be the clearance on the sides of the insert itself. Love to hear all about your adventures. Lots and lots of fun!
 
I’m agreeing with Susq, but for $3.92 so what (plus an insert of a pretty common configuration - SP probably already has). A little front edge grinding, or just lift the tool a bit and one can get in far enough to get the job done (referring to achieving a chamfered bore edge - no off colour comments). Yeah, sometimes I overthink and over complicate things.
 
After I removed the compound (no longer needed, software can emulate the compound with CNC), and beefing up the cross slide, my little machine is much more rigid. I get mirror like finish with carbide if I crank up the RPM towards 2000 (depending on what I'm tuning).

At some point I will take a crash course on HSS grinding but for now I'm a lazy carbide guy.
 
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