Slewmaster - CFA vs. VFA "Rumble"

No. It was unstable. I feared hurting my ops so I put it aside until you and Pete got it resolved. So now I have Krypton-V, infidel and Eye see all built and none singing. These new designs are a bit tougher to get right.

Yes , this is why I need my own amp. Even as you and Thimios are great
builders/prototypers , it would help to debug "in-house".

I will try BV's suggestion (thanks) for the Infidel.

OS
 
OS,
Without knowing the actual hole size in those output devices I would think an 8-32 tap or 6-32 would work fine, at least it would have enough clamping force to keep it tight up against the chassis. I wouldn't use any 24 count thread for this as it may not stay tight over time. Just my opinion here.

Got beat to the punch but 4-40 seems rather small to me.
 
What amplifier?

Hi, this is with what i have on hand.
Unfortunately transformer voltage is only 2x16V.🙁
 

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Last edited:
I used 8-32 and had to make the device holes a tad larger. Funny, this is
what the Genesis Stealth used - (my last big amp - in 2009)
they had to drill their IRFP240's. ??

This time , I have no tap , .... and maybe my nearly useless "tourist oriented"
local hardware store will have a proper metric one.
If not , amazon will provide. 😀

PS - this amp will be perfect - 0 errors. I will take my time to get it "OEM
style".

OS
 
I did all the 20-30 holes on the Genesis heatsinks with no snapped taps.

Plenty of motor oil , tap - backout - tap- backout. Actually used a pair
of vice-grips as my tap driver. 😱

OS

It sounds scary but a cordless drill works better for freehand tapping than anything. Much easier to keep it straight. I do mine in a milling machine. Usually you want alcohol or mineral spirit base cutting fluids for aluminum. Diesel fuel or kerosene works. Oils are for harder metals.
 
Use a two flute tap in aluminum and not a 4 flute like you can with steel. This allows for the the chips to get out of the way and not jam up the tap in the soft aluminum. A lite oil should work fine when tapping by hand, on a machine where you are working at higher speeds you need the correct tapping fluid.

OS, your method of backing in and out is the safest when hand tapping aluminum if is just so easy to break a small tap in aluminum when the chips seize up the tap.
 
I used to use 4-40 bolts before I found a local shop called "Nutty Bolts" who carries metrc button head allen bolts. I used to snap 4-40 taps all the time. I have only snapped one 3M tap in the past year. 3mm bolts fit all the transistors. 6-32 only fit a few. I use cutting wax for tapping, drilling and cutting
 
It sounds scary but a cordless drill works better for freehand tapping than anything. Much easier to keep it straight. I do mine in a milling machine. Usually you want alcohol or mineral spirit base cutting fluids for aluminum. Diesel fuel or kerosene works. Oils are for harder metals.

I notice you have slewmaster pilot holes on your "areospace" heatsinks.

Do you have a template for this (pdf/.bmp/.jpg). Would be cool just to
print it out - line it up.

OS