Geez, I thought this was Do It Yourself, not Do It With Machinery!
In the last couple of years I must have drilled and tapped a couple hundred holes in aluminum, and every single one by hand. Drill Press schmill press, you don't need it, especially if your only doing a few. I use the Irwin taps from Home Depot, put a drop of bicycle chain lubricant on the tap before I start, and I've never broken a tap. When doing it by hand there is a simple recipe for not breaking taps, if you have to put much force into it, then your going to break the tap, which indicates that one of three things is happening:
1) The hole diameter is too small for the tap you are using (Irwin has some great drill/tap charts on their website).
2) The tap is misaligned with the hole.
3) If working on a blind hole (i.e. one that does not go all the way through), the tap has bottomed out in the drill hole.
To summarize, if tapping by hand using lubricant, the force necessary to break a tap is much, much lower than the force required to form the threads. If you find yourself thinking that you might break the tap, chances are pretty good that you are!
Oh, I forgot one last important step in tapping by hand. Turn the tap one full rotation clockwise (cutting new thread), stop, turn the tap counter closckwise 1/4 turn to break the chips, and repeat until finished. This will keep the turning force necessary to cut the threads as low as possible.
OK, now I feel like an old geezer telling my grandchildren that in my day I had to walk to school at -60° uphill both ways with no shoes. Doh!
In the last couple of years I must have drilled and tapped a couple hundred holes in aluminum, and every single one by hand. Drill Press schmill press, you don't need it, especially if your only doing a few. I use the Irwin taps from Home Depot, put a drop of bicycle chain lubricant on the tap before I start, and I've never broken a tap. When doing it by hand there is a simple recipe for not breaking taps, if you have to put much force into it, then your going to break the tap, which indicates that one of three things is happening:
1) The hole diameter is too small for the tap you are using (Irwin has some great drill/tap charts on their website).
2) The tap is misaligned with the hole.
3) If working on a blind hole (i.e. one that does not go all the way through), the tap has bottomed out in the drill hole.
To summarize, if tapping by hand using lubricant, the force necessary to break a tap is much, much lower than the force required to form the threads. If you find yourself thinking that you might break the tap, chances are pretty good that you are!
Oh, I forgot one last important step in tapping by hand. Turn the tap one full rotation clockwise (cutting new thread), stop, turn the tap counter closckwise 1/4 turn to break the chips, and repeat until finished. This will keep the turning force necessary to cut the threads as low as possible.
OK, now I feel like an old geezer telling my grandchildren that in my day I had to walk to school at -60° uphill both ways with no shoes. Doh!
Hey Brian,
A little nitpick about the ol' Twisted Pair website. You misspelled my last name 🙄
Don't feel bad, because for a four letter word, my name is frequently missed, in fact it is more often misspelled than used correctly. You wouldn't believe the number of permutations of misspelling I get, it is to the point that when I introduce myself I say my name and automatically follow by spelling it out phonetically, which is mostly futile because most people still misspell it anyway. In fact I giggled happily like a schoolgirl when Russ got it right on the first attempt on the board silkscreens.
So if it ain't too much trouble, could you change the "Alben" to an "Aben". If you do I promise I'll tell you a humorous story about my name ... 😉
Cheers, Terry
A little nitpick about the ol' Twisted Pair website. You misspelled my last name 🙄
Don't feel bad, because for a four letter word, my name is frequently missed, in fact it is more often misspelled than used correctly. You wouldn't believe the number of permutations of misspelling I get, it is to the point that when I introduce myself I say my name and automatically follow by spelling it out phonetically, which is mostly futile because most people still misspell it anyway. In fact I giggled happily like a schoolgirl when Russ got it right on the first attempt on the board silkscreens.
So if it ain't too much trouble, could you change the "Alben" to an "Aben". If you do I promise I'll tell you a humorous story about my name ... 😉
Cheers, Terry
Fixed!
Okay, just for the record. The Tapomatic will only be used if we decide to sell pre-tapped heatsinks (or maybe some cases), and I need to make, say, 50-100 with 5 holes each. Don't want people thinking I'm a lazy sort. 😉
Okay, just for the record. The Tapomatic will only be used if we decide to sell pre-tapped heatsinks (or maybe some cases), and I need to make, say, 50-100 with 5 holes each. Don't want people thinking I'm a lazy sort. 😉
OK, my proper name is Terence Aben. Terence meaning "good gracious and kind" and Aben translates as "evening". This combination occurred without my parents giving any thought to the inner meanings of the words. So ultimately they named mme with a salutation "Good Evening". It gives me a good little joke, as whenever I hear anyone say good evening, I respond with "Yes, and your name is?"
Hey, I figure if you can laugh at yourself, it becomes less bothersome to have others laugh at you.😀
Hey, I figure if you can laugh at yourself, it becomes less bothersome to have others laugh at you.😀
My wife's maiden name is Demers. Her parents seriously considered naming her Poulet, but settled on something less mean.
Rough translation: "Chicken of the Sea"
Rough translation: "Chicken of the Sea"
going further off topic : )
Esmeralda: What is your name?
Butch: Butch.
Esmeralda: What does it mean?
Butch: I'm American, honey. Our names don't mean sh*%.
Esmeralda: What is your name?
Butch: Butch.
Esmeralda: What does it mean?
Butch: I'm American, honey. Our names don't mean sh*%.
chipco3434 said:
So I got a price from Avel today. For the torroid I described earlier we could get those for about $35 each, but it would take about 6-8 weeks at least to get them made. Thats a big bummer. Good price, but would take a loooooong time coming.
Now I went ahead and called John at Victoria too, and asked for some specs with dual 50/60hz primaries and got a rough estimate of around $50 which is more, but not really aweful for a custom job.
For refresher here are the specs:
dual 115V 50/60hz primaries
one 56VRMS .5A secondary
one 22VRMS .5A secondary
John says his trafo will probably actually be slightly bigger (current wise) than specified as we are running toward his smallest core.
If there is enough interest Brian and I may entertain ideas of buying a whole batch of them to provide you folks.
Anyway just something to mull over.
Cheers!
Russ
Member
Joined 2002
I've ordered from John before. It took 2.5 times as long to get the transformers as he said it would take, so I'd factor this in. I don't think he will turn out to be faster.
To be fair, John's transformers are high quality, but he is a one man
operation. If you are not the patient type, i'd look elsewhere.
operation. If you are not the patient type, i'd look elsewhere.
ignorant question of the day
Sorry if I missed this from somewhere else, but can anyone tell me what the input impedance of the preamp should be? I am guessing 100K because of the 100K resistors to GND on the inputs.
Thanks!
Russ
Sorry if I missed this from somewhere else, but can anyone tell me what the input impedance of the preamp should be? I am guessing 100K because of the 100K resistors to GND on the inputs.
Thanks!
Russ
Toroid solution
I called Avel back today asking if there was a better solution for us, and we found what I think is an excellent solution.
Instead of one big (expensive) custom trafo we will offer a pair of stock Avel trafos with the following specs:
2 x 30Vrms secondaries at .83A(50 VA)
2 x 12Vrms secondaries at 1.25A(30 VA)
both have dual 115V 50/60hz primaries
These trafos can be available right now as they are in stock.
We would offer the pair plus mounting hardware at $35 plus shipping.
This is much more current capability than we had originally specified, and should be much more than what is required for a pair of preamp channels, but at that price it is very reasonable to go fully monoblock.
Please respond if you are interested, if there is interest Brian and I will setup orders on our site.
I am going to go ahead and get a pair from Avel to test on my preamp, just to be sure they work as well as we hope they will.
Cheers!
Russ
I called Avel back today asking if there was a better solution for us, and we found what I think is an excellent solution.
Instead of one big (expensive) custom trafo we will offer a pair of stock Avel trafos with the following specs:
2 x 30Vrms secondaries at .83A(50 VA)
2 x 12Vrms secondaries at 1.25A(30 VA)
both have dual 115V 50/60hz primaries
These trafos can be available right now as they are in stock.
We would offer the pair plus mounting hardware at $35 plus shipping.
This is much more current capability than we had originally specified, and should be much more than what is required for a pair of preamp channels, but at that price it is very reasonable to go fully monoblock.
Please respond if you are interested, if there is interest Brian and I will setup orders on our site.
I am going to go ahead and get a pair from Avel to test on my preamp, just to be sure they work as well as we hope they will.
Cheers!
Russ
I would be interested, especially if you haven't already shipped out the rest of the stuff. I would look for true mono, so that would be 4 pcs total, if I am not mistaken.
Sandy.
Sandy.
Some notes on tapping for the faint of heart...
Buy decent taps... always HSS (high speed steel) never carbon.
Four flute taps are the novice's #1 enemy. They absolutely will not tap without frequent reversals to break chips and withdrawals to remove chips. The more flutes, the weaker the tap. ALL machining processes are governed by the ability to remove chips from the work. When chips clog gullets and flutes, the process becomes uncontrolable. Lose the four flute taps...
Two flute taps are a littel more challenging to start straight but offer the possibility to tap without reversal due to much larger flute area and front chip ejection (gun tap).
The right drill is half the battle. I use only "screw machine length" (short) split point (chisel geometry) drills. The short length and split point prevents ANY walk before the drill digs in... no center punch or center drill required.
After drilling, chamfer the top of the hole... it avoids the cobbler look. My favorite is a single flute counter sink.
I use a rechargable electric drill for most tapping but hand tap #4 and smaller.
For aluminum, never use "gold" TIN (titanium nitride) taps. Aluminum tends to gall on the TIN. The best taps for aluminum are typically uncoated but chromed works very well (Netco Chrome Clad).
Best lubricants for aluminum... kerosene or diesel. Better is 4% lard in kerosene. There are obviously some outstanding commercial products... TrimTap and TapMagic are two examples.
Virtually all DIY audio tapping is cabinetry stuff or board mounting. There is no reason to push the envelope on theoretical thread engagement... no need for 76% when 68% will work just dandy... the finished product won't be flying or traveling at Mach 3.
Little known fact... motor oil as a tap lubricant is WORSE than NO lubricant in tapping steel... Source is the Machinist's Handbook. Fact 2 - Lubricant for machining Lexan and Plexi... Formula 409 or Fantastik.
Just my 2 cents...go pop a few holes.
Buy decent taps... always HSS (high speed steel) never carbon.
Four flute taps are the novice's #1 enemy. They absolutely will not tap without frequent reversals to break chips and withdrawals to remove chips. The more flutes, the weaker the tap. ALL machining processes are governed by the ability to remove chips from the work. When chips clog gullets and flutes, the process becomes uncontrolable. Lose the four flute taps...
Two flute taps are a littel more challenging to start straight but offer the possibility to tap without reversal due to much larger flute area and front chip ejection (gun tap).
The right drill is half the battle. I use only "screw machine length" (short) split point (chisel geometry) drills. The short length and split point prevents ANY walk before the drill digs in... no center punch or center drill required.
After drilling, chamfer the top of the hole... it avoids the cobbler look. My favorite is a single flute counter sink.
I use a rechargable electric drill for most tapping but hand tap #4 and smaller.
For aluminum, never use "gold" TIN (titanium nitride) taps. Aluminum tends to gall on the TIN. The best taps for aluminum are typically uncoated but chromed works very well (Netco Chrome Clad).
Best lubricants for aluminum... kerosene or diesel. Better is 4% lard in kerosene. There are obviously some outstanding commercial products... TrimTap and TapMagic are two examples.
Virtually all DIY audio tapping is cabinetry stuff or board mounting. There is no reason to push the envelope on theoretical thread engagement... no need for 76% when 68% will work just dandy... the finished product won't be flying or traveling at Mach 3.
Little known fact... motor oil as a tap lubricant is WORSE than NO lubricant in tapping steel... Source is the Machinist's Handbook. Fact 2 - Lubricant for machining Lexan and Plexi... Formula 409 or Fantastik.
Just my 2 cents...go pop a few holes.
Re: Toroid solution
Any idea how much the shipping costs would be tothe Netherlands (for 4 trafoos, 2*mono PS).
Probably I have add 25% to the total for taxes, so it may be better for me to buy the toroids at Schuro (via promitheus).
Russ White said:
Any idea how much the shipping costs would be tothe Netherlands (for 4 trafoos, 2*mono PS).
Probably I have add 25% to the total for taxes, so it may be better for me to buy the toroids at Schuro (via promitheus).
FYI: Kit Output Caps
So, as I have previously mentioned, I have several Jantzen output caps (~130) on backorder. PartsExpress (supplier) is saying the ETA is currently 2/7, which is a week later than I had originally been told. The date seems to slip a little every few days.
I currently have enough of the output caps for 14 kits. Everything else in in stock. I have an email into PE for some better information on arrival time, and will post as soon as I get it.
I *could* look for alternatives, either from PE (such as a Dayton Audio equivelent) or elsewhere. I will be doing some more research while I wait for a response. I found a European source for the caps, but they are a LOT more expensive. I will continue to look. If anyone has ideas, send me an email.
So, as I have previously mentioned, I have several Jantzen output caps (~130) on backorder. PartsExpress (supplier) is saying the ETA is currently 2/7, which is a week later than I had originally been told. The date seems to slip a little every few days.
I currently have enough of the output caps for 14 kits. Everything else in in stock. I have an email into PE for some better information on arrival time, and will post as soon as I get it.
I *could* look for alternatives, either from PE (such as a Dayton Audio equivelent) or elsewhere. I will be doing some more research while I wait for a response. I found a European source for the caps, but they are a LOT more expensive. I will continue to look. If anyone has ideas, send me an email.
Well, the guesstimate of weight is 2.2lbs (~1kg) for a pair. So running with that, say 4.4lbs, which puts you in the Airmail Parcel Post category, at 68oz (sorry for all the imperial measures), which is $28.70, plus packaging (I need to buy boxes to ship in), so say about $30 or so. This is all estimation until we actually get a few to look at.
I may be able to do some multi-package things, which would let me chip them for less. One idea is putting them in Global Priority Flat Rate Envelopes (my preferred method anyway), which have a 4lb max (if they fit). That would be $9.50 per envelope, or $19.
Just a note: My experience is when I send 2-3 packages to the same address at the same time, customs seems to be more interested in them.
Anyway, Russ has a couple going to him right now, and as soon as we get our hands on them, I will be able to tell you more.
Incidently, I am working on, and should soon release, a new version of the website. It has a shopping cart, so it shoudl be a lot easier to use. I also wrote a shipping calculator, so you can see/get/select actual shipping charges, rather then the ballpark shipping we currently use. However, you will also see a handling fee for each order, which accounts for PayPal fees and shipping materials (if applicable - supplies for US Priority Mail and Global Priority are free). It will all get spelled out on the screen.