Looking good so far. It's a compact case but still a two man job to lift it likely.
It's a tough go to get every hole lined up even with a drill press. The drill likes to run in aluminum. A good center drill to start helps. I didn't think to send one. I usually drill on the milling machine so I don't have the issues.
I have Silpad sheets that you cut to size. I'll see if I can find the thermal specs on it. I think Sanken likely had some issues with other products for them to send their own though.
It's a tough go to get every hole lined up even with a drill press. The drill likes to run in aluminum. A good center drill to start helps. I didn't think to send one. I usually drill on the milling machine so I don't have the issues.
I have Silpad sheets that you cut to size. I'll see if I can find the thermal specs on it. I think Sanken likely had some issues with other products for them to send their own though.
I have some special drill for metal, looking a little like the ones for the wood, with a a central spike that work pretty well in Aluminium.
But it is true that this metal use to prefer the holes elsewhere than you.
I've never seen a special drill bit for aluminum but you're describing sounds like it would work. Aluminium needs to a very sharp cutter with higher relief angles much like wood cutters. I've never tried it but a good quality brad point wood bit with enough coolant might work.
Those drills are called pilot drills. The smaller diameter is the pilot and starts the hole. If you use a center punch or transfer punch before you try and drill a hole it won't normally have any problem staying on center with a simple drill press. If you have your heat sinks before you build the amplifier section you can clamp the board to the sink and use a transfer punch to accurately mark the centers of the holes you will drill and they will line up perfectly every time. It sounds like the taps sent to OS are high relief 2 or 3 flute taps made for soft materials such as aluminum. Just stay away from 4 flute taps as they have a tendency to break in aluminum with not enough clearance for the chips you make with the tap.
Looking good so far. It's a compact case but still a two man job to lift it likely.
It's a tough go to get every hole lined up even with a drill press. The drill likes to run in aluminum. A good center drill to start helps. I didn't think to send one. I usually drill on the milling machine so I don't have the issues.
I have Silpad sheets that you cut to size. I'll see if I can find the thermal specs on it. I think Sanken likely had some issues with other products for them to send their own though.
This amp weighs in at 55+ lbs ( @25kg). 9kg trafo , 3-4kg heatsinks ....
Excellent workout to carry it around , at least the kids can't run off with it.
If I had a well lit , well endowed workspace - OMG ... I have been assembling
this amp in a dark closet and can come awful close. Sloppy DIY has no excuse ,
there is NO hurry or "race" to get this to production.
I have smaller starter drills "1/16" , I broke one off in a hole that came through (luckily)
pushed it out the other side.The 2.xx mm bit broke too - but a
7/64" will do the 3mm tapped holes well (I have 3 of them).
1/2 way through with a 1/16 and then ALL the way with the 7/64" - tap.
Imagine Canola oil for drilling lube
- but it works.PS - almost done with #2 now.
OS
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One trick that works well is to get what are called stub drills, they are much shorter and are stronger, they have a fatter body section and they don't snap off as easily as a normaljobber length drill. You use them to make the initial hole and if the metal is thick you follow up with a normal jobber drill.
Assembling is a lot more time consuming than one would think. There's hours in just tying the wiring depending on how nice a job you want to do.
Stub drills definitely help with breakage but the biggest problem with aluminum is heat. If there's chips stuck in the flute it will get warm, then the aluminum will stick and jamb everything up. You need to keep pulling the bit out and cleaning it. It's called peck drilling. Same goes for tapping. Canola oil will work. It may work better thinned out (easier to remove all the chips after too). Really anything that stops the aluminum from sticking to the tool is a good thing. When drilling or milling the spray mist or flood coolant is 95% water. The rest is a bit of lubricant (vegetable oil base or synthetic) and antibacterial additives.
Stub drills definitely help with breakage but the biggest problem with aluminum is heat. If there's chips stuck in the flute it will get warm, then the aluminum will stick and jamb everything up. You need to keep pulling the bit out and cleaning it. It's called peck drilling. Same goes for tapping. Canola oil will work. It may work better thinned out (easier to remove all the chips after too). Really anything that stops the aluminum from sticking to the tool is a good thing. When drilling or milling the spray mist or flood coolant is 95% water. The rest is a bit of lubricant (vegetable oil base or synthetic) and antibacterial additives.
Use WD40 for drilling and tapping aluminium. Turn the tap forwards 1/2 to 1 turn to create the new thread and then back off 1/2 turn to dislodge swarf in the hole (prevents breaking the tap) If tapping a blind hole, remove tap every few turns and blow out/pick out swarf stuck in the hole before continuing.
At least no one made fun of the Canola - high temp chicken frying canola
(chicken tonight).The "chicken grease" amp (# 2) came out better ! Nothing broke.
Almost a machine perfect job.
All "tapped out" again , I'll wait to power up with my 40 V supply.
Wolverine test IPS will test out all the OPS's ,with all tested and good OPS's
... then any IPS will test out on it's own (less guessing than with a IPS/OPS).
"Wolverine" is all CCS's - any supply voltage / same performance.
OS
304 stainless is miserable to machine too. If you don't catch a dull insert in time it goes hard and you can't cut it. Chinese inserts don't last at all in it.
Aluminum goes dead soft and mushy as soon as it gets warm. That's when it sticks.
warm/sticky is supposed to go out the flutes - ever feel the harder aluminum
stuck at the business end of a bit /? (if you don't lube) .... that's the al2o3.
An anodized heatsink will dull a bit even with lube - it's already an oxide.
My heatsink bit is much duller than my plain AL bit , even after 50 uses.
OS
That's actually the purpose of anodizing. High speed controlled oxidization for a tougher surface. I just bought a couple boxes of battery acid and some dye. I'm going to try it out.