POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?

rwdenney said:
Now that you are retired, audio makes a good hobby—fun, multidimensional, not too expensive, and time-consuming.
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I beg to differ. Audio might be cheap to start, but it's easy to get sucked down that rabbit hole!

https://quantasylum.com/products/qa401-audio-analyzer
https://quantasylum.com/blogs/news/sneak-peek-the-qa402

Been building my own amps on/off for years. Never really listen to them, but still like building them. Getting the noise floor down, THD down, PSRR up, BW below and above audio spectrum, and especially keeping phase shifts to near zero degrees can become an obsession.

AmpNoisefloor.png

Like every other 'audio phool' out there, have my own opinion of what sounds good. Have my own theories of what makes a better sounding amp. When the last one in the this series of builds was done, it was so clean you could hear night and day differences between most digital recordings, and even digital players. Unfortunately, that sort of ruined it. Eventually ended up listening, and hearing the flaws in the recordings and not really enjoying the music.
 
dkemppai said:
I beg to differ. Audio might be cheap to start, but it's easy to get sucked down that rabbit hole!

https://quantasylum.com/products/qa401-audio-analyzer
https://quantasylum.com/blogs/news/sneak-peek-the-qa402

Been building my own amps on/off for years. Never really listen to them, but still like building them. Getting the noise floor down, THD down, PSRR up, BW below and above audio spectrum, and especially keeping phase shifts to near zero degrees can become an obsession.

View attachment 445333

Like every other 'audio phool' out there, have my own opinion of what sounds good. Have my own theories of what makes a better sounding amp. When the last one in the this series of builds was done, it was so clean you could hear night and day differences between most digital recordings, and even digital players. Unfortunately, that sort of ruined it. Eventually ended up listening, and hearing the flaws in the recordings and not really enjoying the music.
Click to expand...
Give yourself the opportunity to test blindly. You might be surprised by what you can and can’t really hear when your mind doesn’t already know what it’s listening to.

I’ve done that, and was surprised. I ended up with a powerful but relatively inexpensive amp that is nominally cleaner that my previous amps though I can’t hear the difference. But I also ended up with much better speakers than my old Advents, and much better room equalization.

I play tuba along with orchestral recordings from time to time, and so want to be able to play the system at high listening levels without compression or clipping so I would not have to hold back. That took 350 watts/channel into 90-dB speaker sensitivity, and largish speakers with wide, smooth directivity.

Rick “never built his own amp, however” Denney
 
Today, I used the tool that I use to make tools for my tools. I made a tool for another tool that I sometimes also use to make tools. Then there is the tool who makes the tools and gets dust all over his shop in the process.

These are some premium grinds, a RH workhorse and a facing tool, both for cutting steel. The 3/4 MoMax wasn't too bad to grind, heat control was really easy. I roughed them to shape with no relief on an old HF disc sander, then grind the reliefs and rakes in on the Sheckel grinder. I got some NOS Norton 53A wheels in a coarse 46 grit just for this purpose, turned out to be a good choice as the work was fast and reasonably cool compared to running finer stones.

Anyway, here's a pic. The small tools are for puny lathes.

PXL_20230423_220620810.jpg

Don't be a girly man with puny HSS, get pumped up!
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Got some more work done on the countershaft pulley, though more like two steps forward one step back

Found a piece of what I thought was stainless (more on that later), drilled a pilot, then a big hole and bored the od to size
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Jb welded it overnight
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Then came the misery - snapped off or cracked the tip of my poly v cutter so many times it was like that stick of HSS was disappearing before my eyes. Tried neutral rake, positive rake, more or less side clearance, above/on/below center, between centers and then in the 4 jaw. Nothing really worked. I was getting one groove (I need 10!) per tip but the final straw was needing to resharpen it twice for one groove.
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Fudge this for a game of soldiers! So I turned off that nasty azz piece of steel and even that took two and a half CCMT inserts!
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Finishing up a replacement alu ring so I can leave that gluing up overnight. What a nightmare. It took 30min to cut all TEN grooves in the alu piece!!

Still, on the plus side I'm really good at grinding 40deg included angle poly v cutters :)
 
rwm said:
What do you think the problem was? The material? Came out looking great.
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It was either the material or I did something nasty to it when I drilled it out with that 1-5/16" drill. It's weird as it drilled fine, but wouldn't cut with the grooving tool until it did and then it jammed, snapping off the tip. Work holding or cutter geometry, even spindle speed didn't seem to have an effect

I think it was just cursed.
 
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