|
Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al. Steve |
Filament Question
Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al. Steve |
Biz WDØHCO wrote:
After 31 years and a bunch of parts in the garage, I am finally building my dream CW receiver from scratch. Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage if doing so would be worth the effort to reduce hum. Opinions ? Also I would like to cut a round 4" diameter hole in the 1/8" aluminum front panel for the speaker grill. Is there a way to do this without a Greenlee Pneumatic punch? I have a jig saw which I can cut square holes but round holes are another matter. Is there a better way? I can drill round holes up to 7/8" with a unibit but I think 7/8" is as big as they get. Thanks Biz - WDØHCO A jig-saw should be able to cut a 4 inch dia hole. There are also drill held hole cutters that have a lathe type cutter on the end of a rotating arm..Mean looking device when it rotates but it does a good job.. 73 de VE3JUA |
Biz WDØHCO wrote:
After 31 years and a bunch of parts in the garage, I am finally building my dream CW receiver from scratch. Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage if doing so would be worth the effort to reduce hum. Opinions ? Also I would like to cut a round 4" diameter hole in the 1/8" aluminum front panel for the speaker grill. Is there a way to do this without a Greenlee Pneumatic punch? I have a jig saw which I can cut square holes but round holes are another matter. Is there a better way? I can drill round holes up to 7/8" with a unibit but I think 7/8" is as big as they get. Thanks Biz - WDØHCO A jig-saw should be able to cut a 4 inch dia hole. There are also drill held hole cutters that have a lathe type cutter on the end of a rotating arm..Mean looking device when it rotates but it does a good job.. 73 de VE3JUA |
On Wed, 29 Oct 2003 07:42:08 -0800, W7TI wrote:
On Wed, 29 Oct 2003 08:33:36 -0500, Eskay wrote: There are also drill held hole cutters that have a lathe type cutter on the end of a rotating arm..Mean looking device when it rotates but it does a good job.. _________________________________________________ ________ I have one of these but I would NOT recommend it. Way too hard to control and dangerous to boot. Use a hole saw instead. I thought the ones with the rotating arm were intended for use with a drill press, not for a handheld drill. There is a lot of torque from that lever arm, and a moment of inattention could result in serious injury. A hole saw is far safer with a handheld drill. Make sure you get one that will work with metal, though, the wood cutting ones only do wood and some plastics. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
On Wed, 29 Oct 2003 07:42:08 -0800, W7TI wrote:
On Wed, 29 Oct 2003 08:33:36 -0500, Eskay wrote: There are also drill held hole cutters that have a lathe type cutter on the end of a rotating arm..Mean looking device when it rotates but it does a good job.. _________________________________________________ ________ I have one of these but I would NOT recommend it. Way too hard to control and dangerous to boot. Use a hole saw instead. I thought the ones with the rotating arm were intended for use with a drill press, not for a handheld drill. There is a lot of torque from that lever arm, and a moment of inattention could result in serious injury. A hole saw is far safer with a handheld drill. Make sure you get one that will work with metal, though, the wood cutting ones only do wood and some plastics. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
Swells8044 wrote:
Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few holes in al. Steve And use oil or something to keep the Al. from sticking to the teeth. Bill K7NOM |
Swells8044 wrote:
Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few holes in al. Steve And use oil or something to keep the Al. from sticking to the teeth. Bill K7NOM |
W7TI writes:
On Tue, 28 Oct 2003 18:38:39 -0600, Biz WDØHCO wrote: Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage if doing so would be worth the effort to reduce hum. Opinions ? AC will work fine, but here's the key: Don't ground either side of the 6.3 volt line. Many hum problems are caused by ground loops where one side of the filament voltage is run through the chassis. Manufacturers used to do this to save a few pennies by having only one filament wire. In a mass production situation this can be made to work, but for one-off design it's easier and better to just keep the filament voltage isolated from the chassis or anything else. Use a twisted pair and run it from socket to socket. If I did this I would put a 0.01 uF capacitor to ground at each filament pin, to keep RF from propegating through the wires. I would also put a resistor to ground somewhere in the string to bleed off any stray leakage current (maybe 1000 ohms or so), otherwise you might get voltage buildup that could cause problems. What about an inadvertent short between the cathode and filament? Allen |
W7TI writes:
On Tue, 28 Oct 2003 18:38:39 -0600, Biz WDØHCO wrote: Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage if doing so would be worth the effort to reduce hum. Opinions ? AC will work fine, but here's the key: Don't ground either side of the 6.3 volt line. Many hum problems are caused by ground loops where one side of the filament voltage is run through the chassis. Manufacturers used to do this to save a few pennies by having only one filament wire. In a mass production situation this can be made to work, but for one-off design it's easier and better to just keep the filament voltage isolated from the chassis or anything else. Use a twisted pair and run it from socket to socket. If I did this I would put a 0.01 uF capacitor to ground at each filament pin, to keep RF from propegating through the wires. I would also put a resistor to ground somewhere in the string to bleed off any stray leakage current (maybe 1000 ohms or so), otherwise you might get voltage buildup that could cause problems. What about an inadvertent short between the cathode and filament? Allen |
the 6.3 VAC is ok ,no need to go into the fuss for dc.
dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. 73's -- http://www.qsl.net/sv1hao "Biz WDØHCO" wrote in message ... After 31 years and a bunch of parts in the garage, I am finally building my dream CW receiver from scratch. Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage if doing so would be worth the effort to reduce hum. Opinions ? Also I would like to cut a round 4" diameter hole in the 1/8" aluminum front panel for the speaker grill. Is there a way to do this without a Greenlee Pneumatic punch? I have a jig saw which I can cut square holes but round holes are another matter. Is there a better way? I can drill round holes up to 7/8" with a unibit but I think 7/8" is as big as they get. Thanks Biz - WDØHCO |
the 6.3 VAC is ok ,no need to go into the fuss for dc.
dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. 73's -- http://www.qsl.net/sv1hao "Biz WDØHCO" wrote in message ... After 31 years and a bunch of parts in the garage, I am finally building my dream CW receiver from scratch. Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage if doing so would be worth the effort to reduce hum. Opinions ? Also I would like to cut a round 4" diameter hole in the 1/8" aluminum front panel for the speaker grill. Is there a way to do this without a Greenlee Pneumatic punch? I have a jig saw which I can cut square holes but round holes are another matter. Is there a better way? I can drill round holes up to 7/8" with a unibit but I think 7/8" is as big as they get. Thanks Biz - WDØHCO |
On Wed, 29 Oct 2003 19:54:51 GMT, Allen Windhorn
wrote: If I did this I would put a 0.01 uF capacitor to ground at each filament pin, to keep RF from propegating through the wires. I would also put a resistor to ground somewhere in the string to bleed off any stray leakage current (maybe 1000 ohms or so), otherwise you might get voltage buildup that could cause problems. In many audio amplifiers, the filament was powered from a 6.3 V winding with a grounded centre tap. If the centre tap was not available, a potentiometer was connected across the filament winding and the wiper was connected to ground and the wiper was adjusted for minimum hum. In RF applications, using bypass capacitors to ground at each tube is a good idea. Paul OH3LWR |
On Wed, 29 Oct 2003 19:54:51 GMT, Allen Windhorn
wrote: If I did this I would put a 0.01 uF capacitor to ground at each filament pin, to keep RF from propegating through the wires. I would also put a resistor to ground somewhere in the string to bleed off any stray leakage current (maybe 1000 ohms or so), otherwise you might get voltage buildup that could cause problems. In many audio amplifiers, the filament was powered from a 6.3 V winding with a grounded centre tap. If the centre tap was not available, a potentiometer was connected across the filament winding and the wiper was connected to ground and the wiper was adjusted for minimum hum. In RF applications, using bypass capacitors to ground at each tube is a good idea. Paul OH3LWR |
Bill Janssen wrote:
Swells8044 wrote: Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few holes in al. Steve And use oil or something to keep the Al. from sticking to the teeth. Bill K7NOM And DON'T try to use a hand drill! MUST use a drill press! |
Bill Janssen wrote:
Swells8044 wrote: Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few holes in al. Steve And use oil or something to keep the Al. from sticking to the teeth. Bill K7NOM And DON'T try to use a hand drill! MUST use a drill press! |
W7TI wrote:
On Wed, 29 Oct 2003 08:33:36 -0500, Eskay wrote: There are also drill held hole cutters that have a lathe type cutter on the end of a rotating arm..Mean looking device when it rotates but it does a good job.. __________________________________________________ _______ I have one of these but I would NOT recommend it. Way too hard to control and dangerous to boot. Use a hole saw instead. I have used one of these to cut a hole in an aluminum panel. The panel was clamped to a piece of pine and the table on my drill press. The drill press was set to the lowest possible speed and the chuck was lowered slowly. Took a while to cut and the cutter did get stuck a few times requiring me to raise the chuck and clear the problem. Did cut a nice hole, but required a chissel to break out the center and a file to clean up afterwards. |
W7TI wrote:
On Wed, 29 Oct 2003 08:33:36 -0500, Eskay wrote: There are also drill held hole cutters that have a lathe type cutter on the end of a rotating arm..Mean looking device when it rotates but it does a good job.. __________________________________________________ _______ I have one of these but I would NOT recommend it. Way too hard to control and dangerous to boot. Use a hole saw instead. I have used one of these to cut a hole in an aluminum panel. The panel was clamped to a piece of pine and the table on my drill press. The drill press was set to the lowest possible speed and the chuck was lowered slowly. Took a while to cut and the cutter did get stuck a few times requiring me to raise the chuck and clear the problem. Did cut a nice hole, but required a chissel to break out the center and a file to clean up afterwards. |
Paul Keinanen wrote:
On Wed, 29 Oct 2003 23:28:28 +0200, "Deos" wrote: the 6.3 VAC is ok ,no need to go into the fuss for dc. dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. Using a single floating 6.3V secondary winding with a potentiometer connected across it and the wiper connected to the ground and adjusted for minimum hum should be enough. This kind of system works quite well when you have a single high sensitivity input (such as in a radio receiver), but if you have multiple sensitive inputs (as in audio mixing consoles) you would need a separate filament winding for each input tube, in order to be able to adjust the filament balance without compromises. In such situations a DC filament system would be simpler to implement. Paul OH3LWR Except for high gain AF stages, a center tapped filament winding with the center tap grounded should be ok. Otherwise a resistor of a few hundred to a few thousand ohms from each side to ground (resistors of identical value). Use of a pot is probably overkill, but if you have one in the junk box and room to mount it ok. |
Paul Keinanen wrote:
On Wed, 29 Oct 2003 23:28:28 +0200, "Deos" wrote: the 6.3 VAC is ok ,no need to go into the fuss for dc. dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. Using a single floating 6.3V secondary winding with a potentiometer connected across it and the wiper connected to the ground and adjusted for minimum hum should be enough. This kind of system works quite well when you have a single high sensitivity input (such as in a radio receiver), but if you have multiple sensitive inputs (as in audio mixing consoles) you would need a separate filament winding for each input tube, in order to be able to adjust the filament balance without compromises. In such situations a DC filament system would be simpler to implement. Paul OH3LWR Except for high gain AF stages, a center tapped filament winding with the center tap grounded should be ok. Otherwise a resistor of a few hundred to a few thousand ohms from each side to ground (resistors of identical value). Use of a pot is probably overkill, but if you have one in the junk box and room to mount it ok. |
Also I would like to cut a round 4" diameter hole in the 1/8" aluminum
front panel for the speaker grill. Is there a way to do this without a Greenlee Pneumatic punch? I have a jig saw which I can cut square holes but round holes are another matter. Is there a better way? I can drill round holes up to 7/8" with a unibit but I think 7/8" is as big as they get. ========================= Suggest you drill multiple holes ( as close to each other as possible) with a 1/8 inch drill all around a circle with a diameter of 3 13/16 inch . Then knock out the circular bit of aluminium and file with a half round file to 4 inch diameter. It is a bit of a job but will give a good result. Alternatively you can cut out the 4 inch circular bit with a jig saw ,using methylated spirit as 'lubricant'. Finish with a fine file or emery paper. Frank GM0CSZ / KN6WH |
Also I would like to cut a round 4" diameter hole in the 1/8" aluminum
front panel for the speaker grill. Is there a way to do this without a Greenlee Pneumatic punch? I have a jig saw which I can cut square holes but round holes are another matter. Is there a better way? I can drill round holes up to 7/8" with a unibit but I think 7/8" is as big as they get. ========================= Suggest you drill multiple holes ( as close to each other as possible) with a 1/8 inch drill all around a circle with a diameter of 3 13/16 inch . Then knock out the circular bit of aluminium and file with a half round file to 4 inch diameter. It is a bit of a job but will give a good result. Alternatively you can cut out the 4 inch circular bit with a jig saw ,using methylated spirit as 'lubricant'. Finish with a fine file or emery paper. Frank GM0CSZ / KN6WH |
__________________________________________________ _______
Sissy-pants! I've used hand drills many times with hole saws. Just gotta know what you're doing. Like I said, brace the work piece nice and steady and hold on tight. Do you think carpenters use a drill press to make holes in framing? -- Bill, W7TI Seems to me the framing can't move- unlike a piece of sheet metal. I have many times used 2.5" bimetal hole saws to make openings for meters in 0.125 and 0.25" aluminum panels. The panels were in each case held to the mill (or drill press) table with at least 2 clamps. There is absolutely no way that one person could make that size hole with a hole saw w/o clamping. And forget a hand drill if you want the hole to look decent. Dale W4OP |
__________________________________________________ _______
Sissy-pants! I've used hand drills many times with hole saws. Just gotta know what you're doing. Like I said, brace the work piece nice and steady and hold on tight. Do you think carpenters use a drill press to make holes in framing? -- Bill, W7TI Seems to me the framing can't move- unlike a piece of sheet metal. I have many times used 2.5" bimetal hole saws to make openings for meters in 0.125 and 0.25" aluminum panels. The panels were in each case held to the mill (or drill press) table with at least 2 clamps. There is absolutely no way that one person could make that size hole with a hole saw w/o clamping. And forget a hand drill if you want the hole to look decent. Dale W4OP |
In article ,
kenneth scharf wrote: Paul Keinanen wrote: On Wed, 29 Oct 2003 23:28:28 +0200, "Deos" wrote: the 6.3 VAC is ok ,no need to go into the fuss for dc. dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. Using a single floating 6.3V secondary winding with a potentiometer connected across it and the wiper connected to the ground and adjusted for minimum hum should be enough. This kind of system works quite well when you have a single high sensitivity input (such as in a radio receiver), but if you have multiple sensitive inputs (as in audio mixing consoles) you would need a separate filament winding for each input tube, in order to be able to adjust the filament balance without compromises. In such situations a DC filament system would be simpler to implement. Paul OH3LWR Except for high gain AF stages, a center tapped filament winding with the center tap grounded should be ok. Otherwise a resistor of a few hundred to a few thousand ohms from each side to ground (resistors of identical value). Use of a pot is probably overkill, but if you have one in the junk box and room to mount it ok. Maybe he's thinking about the antique radio sets which just ran off batteries. Weren't the filaments run off 6 Vdc? Al -- There's never enough time to do it right the first time....... |
In article ,
kenneth scharf wrote: Paul Keinanen wrote: On Wed, 29 Oct 2003 23:28:28 +0200, "Deos" wrote: the 6.3 VAC is ok ,no need to go into the fuss for dc. dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. Using a single floating 6.3V secondary winding with a potentiometer connected across it and the wiper connected to the ground and adjusted for minimum hum should be enough. This kind of system works quite well when you have a single high sensitivity input (such as in a radio receiver), but if you have multiple sensitive inputs (as in audio mixing consoles) you would need a separate filament winding for each input tube, in order to be able to adjust the filament balance without compromises. In such situations a DC filament system would be simpler to implement. Paul OH3LWR Except for high gain AF stages, a center tapped filament winding with the center tap grounded should be ok. Otherwise a resistor of a few hundred to a few thousand ohms from each side to ground (resistors of identical value). Use of a pot is probably overkill, but if you have one in the junk box and room to mount it ok. Maybe he's thinking about the antique radio sets which just ran off batteries. Weren't the filaments run off 6 Vdc? Al -- There's never enough time to do it right the first time....... |
On Thu, 30 Oct 2003 09:06:55 -0800, W7TI wrote:
On Thu, 30 Oct 2003 13:33:28 GMT, "Dale Parfitt" wrote: Seems to me the framing can't move- unlike a piece of sheet metal. Correct, that's why I said to clamp it securely. I have many times used 2.5" bimetal hole saws to make openings for meters in 0.125 and 0.25" aluminum panels. The panels were in each case held to the mill (or drill press) table with at least 2 clamps. There is absolutely no way that one person could make that size hole with a hole saw w/o clamping. Correct, clamp it. And forget a hand drill if you want the hole to look decent. Incorrect. Easily done if you hold it tightly. Of course you MUST USE a hole saw which has a center drill bit for alignment purposes. I believe there may be hole saws without the center drill bit, made for use ONLY IN A DRILL PRESS. I don't own any of those. Done it with a hand held drill many times, works fine. Yes, one can use a handheld drill with the circular hole cutters with center bit, although a drill press will give a neater job. The problem was with the fly-cutter style, which has a center drill bit and an arm holding the single cutter. Small misalignments will cause a lot of torque to fling the workpiece or the drill. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
On Thu, 30 Oct 2003 09:06:55 -0800, W7TI wrote:
On Thu, 30 Oct 2003 13:33:28 GMT, "Dale Parfitt" wrote: Seems to me the framing can't move- unlike a piece of sheet metal. Correct, that's why I said to clamp it securely. I have many times used 2.5" bimetal hole saws to make openings for meters in 0.125 and 0.25" aluminum panels. The panels were in each case held to the mill (or drill press) table with at least 2 clamps. There is absolutely no way that one person could make that size hole with a hole saw w/o clamping. Correct, clamp it. And forget a hand drill if you want the hole to look decent. Incorrect. Easily done if you hold it tightly. Of course you MUST USE a hole saw which has a center drill bit for alignment purposes. I believe there may be hole saws without the center drill bit, made for use ONLY IN A DRILL PRESS. I don't own any of those. Done it with a hand held drill many times, works fine. Yes, one can use a handheld drill with the circular hole cutters with center bit, although a drill press will give a neater job. The problem was with the fly-cutter style, which has a center drill bit and an arm holding the single cutter. Small misalignments will cause a lot of torque to fling the workpiece or the drill. Happy trails, Gary (net.yogi.bear) ------------------------------------------------ at the 51st percentile of ursine intelligence Gary D. Schwartz, Needham, MA, USA Please reply to: garyDOTschwartzATpoboxDOTcom |
W7TI wrote:
On Wed, 29 Oct 2003 17:04:34 GMT, Gary S. Idontwantspam@net wrote: I thought the ones with the rotating arm were intended for use with a drill press, not for a handheld drill. __________________________________________________ _______ Even in a drill press, I don't like 'em. They can catch on the work piece and fling it who knows where. Use them if you must, but a hole saw is much more user friendly. I've used this kind on metal and wood in a drill press with the work clamped. I really think this kind of cutter was made to cut wood judging on how it worked. In any case I wouldn't use it on steel, only soft metals such as copper or aluminum, and then with a wood backing board. |
W7TI wrote:
On Wed, 29 Oct 2003 17:04:34 GMT, Gary S. Idontwantspam@net wrote: I thought the ones with the rotating arm were intended for use with a drill press, not for a handheld drill. __________________________________________________ _______ Even in a drill press, I don't like 'em. They can catch on the work piece and fling it who knows where. Use them if you must, but a hole saw is much more user friendly. I've used this kind on metal and wood in a drill press with the work clamped. I really think this kind of cutter was made to cut wood judging on how it worked. In any case I wouldn't use it on steel, only soft metals such as copper or aluminum, and then with a wood backing board. |
Al wrote:
In article , kenneth scharf wrote: Paul Keinanen wrote: On Wed, 29 Oct 2003 23:28:28 +0200, "Deos" wrote: the 6.3 VAC is ok ,no need to go into the fuss for dc. dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. Using a single floating 6.3V secondary winding with a potentiometer connected across it and the wiper connected to the ground and adjusted for minimum hum should be enough. This kind of system works quite well when you have a single high sensitivity input (such as in a radio receiver), but if you have multiple sensitive inputs (as in audio mixing consoles) you would need a separate filament winding for each input tube, in order to be able to adjust the filament balance without compromises. In such situations a DC filament system would be simpler to implement. Paul OH3LWR Except for high gain AF stages, a center tapped filament winding with the center tap grounded should be ok. Otherwise a resistor of a few hundred to a few thousand ohms from each side to ground (resistors of identical value). Use of a pot is probably overkill, but if you have one in the junk box and room to mount it ok. Maybe he's thinking about the antique radio sets which just ran off batteries. Weren't the filaments run off 6 Vdc? Al Old radios used 5v tubes off 6v batteries and a rheostat to control filament voltage. I was talking about using resistors to create a center tap for a transformer without one. While this was used to power directly heated tubes off ac, it could be used as a hum balance for heater cathode types. |
Al wrote:
In article , kenneth scharf wrote: Paul Keinanen wrote: On Wed, 29 Oct 2003 23:28:28 +0200, "Deos" wrote: the 6.3 VAC is ok ,no need to go into the fuss for dc. dont take my word for it, after making the nice rig put some diodes on the ac line and you will not see anythig special.. Using a single floating 6.3V secondary winding with a potentiometer connected across it and the wiper connected to the ground and adjusted for minimum hum should be enough. This kind of system works quite well when you have a single high sensitivity input (such as in a radio receiver), but if you have multiple sensitive inputs (as in audio mixing consoles) you would need a separate filament winding for each input tube, in order to be able to adjust the filament balance without compromises. In such situations a DC filament system would be simpler to implement. Paul OH3LWR Except for high gain AF stages, a center tapped filament winding with the center tap grounded should be ok. Otherwise a resistor of a few hundred to a few thousand ohms from each side to ground (resistors of identical value). Use of a pot is probably overkill, but if you have one in the junk box and room to mount it ok. Maybe he's thinking about the antique radio sets which just ran off batteries. Weren't the filaments run off 6 Vdc? Al Old radios used 5v tubes off 6v batteries and a rheostat to control filament voltage. I was talking about using resistors to create a center tap for a transformer without one. While this was used to power directly heated tubes off ac, it could be used as a hum balance for heater cathode types. |
HAVE YOU EVER HEARD OF
DRILLING LOTS OF SMALLER HOLES AROUND THE DIAMATER , UNTILL THE CENTER DROPS OUT AND THEN FILLING THE EDGES SMOOTH THE GOOD OLD FLE WORKS WONDERS ...HMMMM DE PAUL |
HAVE YOU EVER HEARD OF
DRILLING LOTS OF SMALLER HOLES AROUND THE DIAMATER , UNTILL THE CENTER DROPS OUT AND THEN FILLING THE EDGES SMOOTH THE GOOD OLD FLE WORKS WONDERS ...HMMMM DE PAUL |
In article , W7TI
writes: On Sat, 8 Nov 2003 13:27:07 -0000, "uk-hamman" wrote: HAVE YOU EVER HEARD OF DRILLING LOTS OF SMALLER HOLES AROUND THE DIAMATER , UNTILL THE CENTER DROPS OUT AND THEN FILLING THE EDGES SMOOTH THE GOOD OLD FLE WORKS WONDERS ...HMMMM _________________________________________________ ________ This is how our Neanderthal ancestors did it, and if it was good enough for them.... -- Bill, W7TI Practically speaking (as one neanderthal to another...): That method does work if there's no drill press available. But, be sure to buy an extra drill bit for the size desired going around the rim. Had to do that with a 4 1/4" diameter speaker hole in an 1/8" aluminum rack panel (alloy tougher than 2024 but not as stiff as 6061). That included light oil lubrication. The "center" didn't "drop right out" but centerpunching the many holes right allowed using old wire cutters to snip the narrow left-overs between holes. A Hand File to complete?!?!? Good grief, no. A Dremel Moto-Tool with several "mill type" cutter bits is much preferred to smooth out the rough edges. Note: Home Depot, Lowe's, Do-It-Centers, OSH, all carry extra bits for Dremel Moto-Tools, many which aren't included in the Dremel kits. Use a biggie mill cutter to hog out the worst, go to a small bit to smooth those edges. One of several grind wheels can be used to finish it off. Takes a steady hand (usually both hands if panel is in a vise). Absolutely needed: A scribe marked circle on the panel as a guide! Maybe two concentric circles, the inner one slightly smaller than desired as a "target." If one gets sloppy, it's possible to cut farther out than the inner, smaller "target" circle. To get the scribed circle, use a grade-school compass in REVERSE, the "pencil" part in a small drill hole at center, the "center" part (pointy end) doing the scribing. Dremel also makes a dandy mini-drill-press stand for the Moto-Tool which is just lovely for through-hole PCB drilling. I use one for that plus the AC line voltage adjusted with a Powerstat (Superior Electric) variable autotransformer to control the "drill press" speed. BTW, liquid hand soap, slightly diluted, works out as a PCB drilling lubricant and washes out with hot water...and can be used with a rough-surface sponge to buff out surface oxidation on the copper foil or removing tiny burrs in the drill holes. Len Anderson retired (from regular hours) electronic engineer person |
In article , W7TI
writes: On Sat, 8 Nov 2003 13:27:07 -0000, "uk-hamman" wrote: HAVE YOU EVER HEARD OF DRILLING LOTS OF SMALLER HOLES AROUND THE DIAMATER , UNTILL THE CENTER DROPS OUT AND THEN FILLING THE EDGES SMOOTH THE GOOD OLD FLE WORKS WONDERS ...HMMMM _________________________________________________ ________ This is how our Neanderthal ancestors did it, and if it was good enough for them.... -- Bill, W7TI Practically speaking (as one neanderthal to another...): That method does work if there's no drill press available. But, be sure to buy an extra drill bit for the size desired going around the rim. Had to do that with a 4 1/4" diameter speaker hole in an 1/8" aluminum rack panel (alloy tougher than 2024 but not as stiff as 6061). That included light oil lubrication. The "center" didn't "drop right out" but centerpunching the many holes right allowed using old wire cutters to snip the narrow left-overs between holes. A Hand File to complete?!?!? Good grief, no. A Dremel Moto-Tool with several "mill type" cutter bits is much preferred to smooth out the rough edges. Note: Home Depot, Lowe's, Do-It-Centers, OSH, all carry extra bits for Dremel Moto-Tools, many which aren't included in the Dremel kits. Use a biggie mill cutter to hog out the worst, go to a small bit to smooth those edges. One of several grind wheels can be used to finish it off. Takes a steady hand (usually both hands if panel is in a vise). Absolutely needed: A scribe marked circle on the panel as a guide! Maybe two concentric circles, the inner one slightly smaller than desired as a "target." If one gets sloppy, it's possible to cut farther out than the inner, smaller "target" circle. To get the scribed circle, use a grade-school compass in REVERSE, the "pencil" part in a small drill hole at center, the "center" part (pointy end) doing the scribing. Dremel also makes a dandy mini-drill-press stand for the Moto-Tool which is just lovely for through-hole PCB drilling. I use one for that plus the AC line voltage adjusted with a Powerstat (Superior Electric) variable autotransformer to control the "drill press" speed. BTW, liquid hand soap, slightly diluted, works out as a PCB drilling lubricant and washes out with hot water...and can be used with a rough-surface sponge to buff out surface oxidation on the copper foil or removing tiny burrs in the drill holes. Len Anderson retired (from regular hours) electronic engineer person |
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