Tubalcain, Thank you for showing us noobs how to do it the old school way, a pro is a luxury in my world, I was taught that you learned to do it manually and after you had that process perfect you could then go and learn the "easy" way. so thank you again for teaching what is fast becoming a dying art form.
I'm with you, I've been doing this stuff since I was a boy. DRO, CNC make life easier but in the basement with an old Atlas lathe and a drill press some careful layout and some talent goes a really long way.
I never thought about using angle blocks. The first shop I worked for we laid out everything using trammels and figuring out the chord. I have an optical center punch that now collects dust in my tool box. It's been 13 yrs since I've had to use that formula and can still rattle it off. Very interesting video. I always enjoy them.
Another great series with plenty of detail and yes some off topic that is most interesting. I really enjoyed the editorial comment about the Ray O Vac flashlights and their off brand batteries.
This is my favorite layout method It requires less tools for me to do... Thank You for the whole series of videos and the flashlight review... Also showing the Domore drill press
please sir do not EVER decide to stop putting youre machine shop vidios on youtube ,Im new to all this i got myself a small 8x16 vs lathe and it is you and the vidios that have got me to a place were im quite confident at small projects im saving for a small milling machine so once i have that ill be moving on to something a wee bit more adventurous . once again.thank you.
Again nicely presented Mr Pete. I generally just use the rotab and spin it around but if thats is not available it's nice to be able to do it other ways.
Hi mrpete, Excellent tutorial on setting up with minimal tools, that is often the case for majority of folks out there. The double AA MiniMaglite flashlights with the halogen bulb were long lasting body and switches but, the bulb itself was fading and toasting fairly rapidly, maybe one day I will try their LED version. Thanks for sharing, Pierre
sir usually when you shake a flashlight it`s not the switch but the oxide layer over the contacts of the bulb(lead) or the batteries terminals that get knocked off so the current can flow. regards. pete
One of the ways I have used to find the center of small stock, stuff that will fit in a drill press, is to put it in a drill press and press it against sandpaper. A pattern of concentric circles will be left locating the center.
Remember guys, LED flashlights will not dim down to nothing like incandesant bulbs. When the battery voltage hits the low voltage threshold of the LEDs the output will quit, no dimness. Turning the light off then on will sometimes make the LEDs blink then they quit, this means the batteries need replaced or charged. It doesn't mean it's a bad switch.
Great Video. Now I do have the tools to lay out these bolt holes. I just recently got involved in drilling some holes and noticed that if you don't drill a pilot hole the result can be very bad. I had drilled with a bit of the size I wanted with no pilot hole and they all wandered, nothing was lined up. I had made my punch marks starting with a transfer punch through the pattern holes in one piece, supposedly so it would all line up just right. Unfortunately the bit wandered some and the holes did not line up right. I am sure my shop teacher told me that about 50 years ago but I was probably annoying another student or something instead of listening. Thanks for sharing.
Hey Tubal ... One guy I heard of once repaired a table like that by filling the scratches up with JB weld and then facing it again in his lathe. Worked pretty well, by golly ... pretty well indeed!
Just use porportional dividers. They have a scale for dividing circles. You still have to play around with them a little to get the true divisions but it's pretty quick. I layed out 60 divisions for a hot tub with dividers in no time and very accurate.
For bolt circles the component should fit in any position with its mating part. Anything else would be unacceptable in a professional machine shop. This method included.
Great series. You can get 8-LED flashlights for $7. I like one from Northern tools made out of aluminum by Grip Tools. Has a hex head on one end so it does not roll. Even though it uses 3 AAA batts, they last for years. I bought some for family members. Then I saw HomerD had a 6-pack of plastic ones with batteries for $10. Keep up the good vids.
Great Video. I enjoy all your teaching videos. Too bad schools, both high school and tecnical schools seem to have dropped machine shop courses these days. My favorite accessory for the drill press is momentary contact foot switch. It leaves both hands free to position the work and it allows you to move the work around under a drill bit that is not spinning. Once you have the work positioned stepping on the switch makes it easy to start the drilling operation without having to move your hands. As a safety feature if anything unexpected happens, drill grabbing the workpiece or something similar jumping back from the drill press will automatically turn it off.
love it when you go "off topic"! i think we learn as much (if not more) when you do so? by all means, please keep the camera rolling and please keep rambling!!
There is a way to layout accurate 6-holes pattern using only a compass (divider) and a ruler. upload.wikimedia.org/wikipedia/commons/c/cf/HexagonConstructionAni.gif
Mr. Pete. Tabulcain. Whichever you prefer. I have been watching and learning about some machine shop that I am going to be doing soon. Long story short I am going to be creating adapter plate and Crankshaft Adapter for an automotive engine that I am putting into a Tractor. A re-power if you will. I have learned a lot and have chosen to purchase a really neat Craftsman 8 " Rotary table with adjustable X & Y axis pretty much making a drill press into a small Mill. Have you made any video's using something like this ?
And another question. How do you measure for the T-nuts for the Rotary Table ? Looking at E-bay there is Metric Standard , and I am not quite sure how they get the size, Like if it's a 5/8 where did they take the measurement at ? Mine didn't come with any and not sure if a place like Fastenal would even know what these things are.
those neodymium magnets are the best! I have a medium size cube that has a pull off strength of 132lb on 1/8" thick steel! It is now stuck to my locker and there it remains.
I agree with Mike Horn that the divider method should be very accurate if done properly. Be sure that the dividers are still set to the radius of the circle you are laying the bolt pattern on. You are using the dividers to measure the bottom side of a triangle whose other 2 sides are the radii of the circle which meet in the center of that circle forming the apex of the triangle. Since all 3 sides are equal, this makes the triangle equilateral, so all the angles of the triangle are equal at 60 degrees. A full circle is 360 degrees divided by 60 degrees for each triangle makes 6 triangles total in a circle.
Hi mrpete...would it not be possible to perhaps fill in the holes with weld or braze on the platter of your Dumore drill press, then machine the face? Love your videos by the way. Thanks for posting.
drawing a 6 whole pattern with the compass method as demonstrated at the beginning of the vid, this method isn't inaccurate at all. It's common practice since centuries and it's accuracy is proved mathematically. The reasons why the sixth and last "compass stroke" 6 doesn't match the starting point are either that the pencil insert needs to be sharpened or the compass itself is worn with some play or that the compass isn't operated accurate enough.
Seems like you could just mill a new table for that little Dumore press? It looks like a hunk of aluminum, and we've certainly seen you do that before. You could also run a bead with a TIG welder as Duncan suggested below, then grind or mill it flat.
If you ever spring for a rechargeable Maglight with LED's you will never go back to the Yellow Industrial Grade Lights. The Maglight definitely is magnitudes brighter and carries for long distances. Just ask a Law Enforcement Officer.
Many LEOs ditched their Maglites for Streamlights. I'm am aircraft mechanic and if someone gave me a Maglite I'd give it away. I have three Streamlight LED Stingers. LED headlamps blow away flashlights for machinist work for one simple reason. A flashlight requires a hand to hold it. An LED headlamp puts light on the work leaving hands free.
I have another question for you. I am watching this video looking at you Center Finder you are using at time number 3:27. I was wondering what type it is because I would like to purchase one like it.
Could you put it in a 3 jaw chuck on the lathe and scribe three lines with the tool after having plumbed the jaws in the up position, then plumbing again in the down position and scribing again?
Based on it's principle this method for sure isn't the most accurate, however even with the compass you shall normally get a much closer result than what you present in the very beginning. If the deviation is really that big, then you have either a compass which isn't rigid enoug or you've done some operational mistakes.
just look up the magic numbers from page 75 in The Machinery's Handbook. Good for 3 to 194 spaces. My copy is the twentieth edition. My eyes are getting old, may have to order a new copy in large print or a CD but a CD is hard to read in bed!
why so much trouble to determine only 6 holes? If you determined your center hole, take a compass, make a quarter circle on the diameter, from that point you cross that quarter circle and you have a 60° angle, make another straight line through it, and then you can measure the distance with your compass from both diameters crossing the outline, and draw 6 equal length crosssections for all 6 holes. I would even do it on paper just a tiny bit smaller, glue it on, then make your center punch, and just draw, so you can make mistakes, but you'll always have the same center hole.
I like Rayovac batteries, I think they're almost as good as Duracell but cost much less. I think mag-lite makes the best flashlight, you can get the 2D led for around $25, costs more than your Rayovac but excellent quality, and I think they're still made here in the USA. Great video as always!!
Maglites were good 20 years ago because the competition hadn't caught up. They're junk by comparison today. Pelican make excellent lights using modern plastics (handy doing electrical work where a Maglite could short!). Streamlight make superb rechargeables if you have more money. I get better results for less money over time buying quality. For work lights it's hard to beat an LED headlamp because wasting a hand holding a flashlight is awkward on a good day. Any LED headlamp with rechargeable batteries and decent customer ratings will do. I wear them even in well lit rooms when doing precise work. About 20 bucks online from the usual sources.
I grew up with very dim flashlights in Alaska. I got used to letting my eyes adjust to the dark. Now when you are mining and a grizzly smacks your tent the person next too you blinds you with the new super bright flashlight and you run out side and now the bear can see you and you can't see it so I still like dim light when fighting bears at night. And the bears don't stare at the bright lights ether like they do with old dim lights they learn to sneak around the light and make it much harder too know were they are and when you are in the woods at night with a pissed grizzly I rather see the eyes then hear blobbering growls of a devil tough talking beast. Last year I had a grizzly brake trees and talk toughs for 4+ hours and it sound like playing a record backwards and the growls make you feel real small when you see eyes 14feet in the air. ps I never saw the bear could have been Sasquatch hahah
That wasn't a centre punch you were using, it was a prick punch. That's correct practice of course, the less than 60 degree point of a prick punch being followed up with by the greater than 80 degree point of a centre punch. The aim in any case being to have a divot larger than the chisel length of the drill you're going to use.
that compass method should be spot on circumference divided by 6, should be very accurate but you made a mess of it, easier way any cad programme, draw , print, lay paper on the metal
I don't think he 'made a mess of it', he did not adjust for the error in the divider spread which for this 6 hole layout would be 1/6 of the error. Then run it again and you should be very close if not right on. Do it a third time if you are still off but remember only adjust by 1/N th the error where N equals the number of holes drilled.
To set your dividers SMALL TABLE UP TO 12 HOLES at bottom The correct way to work out the distance between the holes (Cord) in the case of seven holes 360/7 = 51.42657143 Deg Then 51.426571243/2 = 25.71428571 then find the SIN of 25.71428571 on your calculator which is SIN(25.71428571) = 0.43388374 All you do is multiply .43388374 by the pitch circle diameter you require TABLE 5 dec places (rounded up) Mutiply PCD by number below 3 holes = .86603 4 holes=.70711 5 holes=.58779 6 holes = .5 7 holes =.43388 8 holes = .38268 9 holes =.34202 10 holes =.30902 11 holes =.28173 12 holes = .25882
I want to see an uneven number like a 5 hole. Was the flashlight made in USA? I like the Mag Lite www.rei.com/product/870252/maglite-xl200-led-flashlight#tab-specs is 172 lumens.
This method clearly has to be very inaccurate. There is a better method using the math to set the dividers. If pi was 3, the mthod would be perfect, but it is as we all know pi= 3.1416 and that .1416 (rounded) is the error. Correction: Multiply the diameter of the first circle times pi and you'll end up with the circumference of that circle. Divide that by the number of holes you want (6 in this case) and you'll end up with an odd but very correct length. Set your dividers to that length and start at any point like shown in the video. Regards
Incorrect. This will give you the arc length. But dividers measure a straight line. You actually want to calculate the side length of the regular polygon circumscribed by the circle, which is given by 2 R sin(pi/n) (in radians).
Rubbish. You are trying to mark the vertices of a regular hexagon. This is formed by six equilateral triangles, each of which has two sides that are obviously radii of the circle and whose third side lies on the circle. The third side should clearly also be the same length. The error is caused by leaning the pair of compasses over at different angles, drawing with different points on the pencil lead.
![Baby Kia - GLOVES & DRACS (BLACK AF1s) [Official Music Video]](http://i.ytimg.com/vi/ajm8LeB0qQk/mqdefault.jpg)
Being 77 years old, I really enjoyed the lesson on placing the center punch. I have spent a lot hours trying to adjust missed points. Thank you.
Tubalcain, Thank you for showing us noobs how to do it the old school way, a pro is a luxury in my world, I was taught that you learned to do it manually and after you had that process perfect you could then go and learn the "easy" way. so thank you again for teaching what is fast becoming a dying art form.
You were taught right
I'm with you, I've been doing this stuff since I was a boy. DRO, CNC make life easier but in the basement with an old Atlas lathe and a drill press some careful layout and some talent goes a really long way.
I like the battery comment, you might think Rayovac would use there own batteries!
Brother guys like you and my Dad are magic with these machines
Thank you
I never thought about using angle blocks. The first shop I worked for we laid out everything using trammels and figuring out the chord. I have an optical center punch that now collects dust in my tool box. It's been 13 yrs since I've had to use that formula and can still rattle it off. Very interesting video. I always enjoy them.
Another great series with plenty of detail and yes some off topic that is most interesting. I really enjoyed the editorial comment about the Ray O Vac flashlights and their off brand batteries.
I built my self a plate like you demonstrated it & tapped hole's so i rotate it on the cercal giving it a lay out paten .
This is my favorite layout method It requires less tools for me to do... Thank You for the whole series of videos and the flashlight review... Also showing the Domore drill press
+not2fast4u2c Thanks for watching
please sir do not EVER decide to stop putting youre machine shop vidios on youtube ,Im new to all this i got myself a small 8x16 vs lathe and it is you and the vidios that have got me to a place were im quite confident at small projects im saving for a small milling machine so once i have that ill be moving on to something a wee bit more adventurous . once again.thank you.
Thanks for watching--more to come
I enjoy watching these tips, including the off topic comments from an “ old school” Master.
Thanks
Thank you Again Mr. Pete ! I truly enjoy all your videos and look forward to the new ones !
Now, these are really good machining videos! Keep those good videos coming!!!
+sgds sd THANKS FOR WATCHING
Again nicely presented Mr Pete. I generally just use the rotab and spin it around but if thats is not available it's nice to be able to do it other ways.
Always something to learn from these videos. Thanks for posting again. :)
Enjoyed the video, learned a lot, thank you for posting.
Another great video! This will be my method probably for the foreseeable future. Thanks!
+Dustin Masters Thanks for watching
Ddazwesxzcccxc loljrxdddrbgk fiñ
x
Dustin Masters i liked emphasizing drilling smaller holes first this just as true drilling in stone or concrete yes it does
Hi mrpete,
Excellent tutorial on setting up with minimal tools, that is often the case for majority of folks out there.
The double AA MiniMaglite flashlights with the halogen bulb were long lasting body and switches but, the bulb itself was fading and toasting fairly rapidly, maybe one day I will try their LED version.
Thanks for sharing,
Pierre
Thanks again your videos are extremely helpful
sir usually when you shake a flashlight it`s not the switch but the oxide layer over the contacts of the bulb(lead) or the batteries terminals that get knocked off so the current can flow. regards. pete
One of the ways I have used to find the center of small stock, stuff that will fit in a drill press, is to put it in a drill press and press it against sandpaper. A pattern of concentric circles will be left locating the center.
thank you very much for this series! very usefull! i am looking forward to your heat treating series! :)
instablaster
Remember guys, LED flashlights will not dim down to nothing like incandesant bulbs. When the battery voltage hits the low voltage threshold of the LEDs the output will quit, no dimness. Turning the light off then on will sometimes make the LEDs blink then they quit, this means the batteries need replaced or charged. It doesn't mean it's a bad switch.
Thanks
Great Video. Now I do have the tools to lay out these bolt holes. I just recently got involved in drilling some holes and noticed that if you don't drill a pilot hole the result can be very bad. I had drilled with a bit of the size I wanted with no pilot hole and they all wandered, nothing was lined up. I had made my punch marks starting with a transfer punch through the pattern holes in one piece, supposedly so it would all line up just right. Unfortunately the bit wandered some and the holes did not line up right. I am sure my shop teacher told me that about 50 years ago but I was probably annoying another student or something instead of listening. Thanks for sharing.
That flashlight brings back memories tubalcain. We used the same ones at the GM factory. I had to bang a few of them to get them to work. LOL
Hey Tubal ... One guy I heard of once repaired a table like that by filling the scratches up with JB weld and then facing it again in his lathe. Worked pretty well, by golly ... pretty well indeed!
I love my optical center punch.
Great information here, thanks.
Very good info in this demo. I agree that LED flashlights are the cat's pajamas.
Yes
very helpful. thank you for sharing
Just use porportional dividers. They have a scale for dividing circles. You still have to play around with them a little to get the true divisions but it's pretty quick. I layed out 60 divisions for a hot tub with dividers in no time and very accurate.
👍
As always, thanks’ for taking the time to make this video! And I support this site. ~M~
THANKS--I appreciate your continued support
For bolt circles the component should fit in any position with its mating part. Anything else would be unacceptable in a professional machine shop. This method included.
Great series.
You can get 8-LED flashlights for $7. I like one from Northern tools made out of aluminum by Grip Tools. Has a hex head on one end so it does not roll. Even though it uses 3 AAA batts, they last for years.
I bought some for family members. Then I saw HomerD had a 6-pack of plastic ones with batteries for $10.
Keep up the good vids.
Great Video. I enjoy all your teaching videos. Too bad schools, both high school and tecnical schools seem to have dropped machine shop courses these days.
My favorite accessory for the drill press is momentary contact foot switch. It leaves both hands free to position the work and it allows you to move the work around under a drill bit that is not spinning. Once you have the work positioned stepping on the switch makes it easy to start the drilling operation without having to move your hands. As a safety feature if anything unexpected happens, drill grabbing the workpiece or something similar jumping back from the drill press will automatically turn it off.
+Larry Small Thanks for watching--I have a floor switch-never got it hooked up
The good old Zeus Engineers' pocket book contains tables for pitch circle diameters, giving the divider spacing formulas.
love it when you go "off topic"! i think we learn as much (if not more) when you do so?
by all means, please keep the camera rolling and please keep rambling!!
+KevCarrico Thank you, I will
There is a way to layout accurate 6-holes pattern using only a compass (divider) and a ruler.
upload.wikimedia.org/wikipedia/commons/c/cf/HexagonConstructionAni.gif
Yup, that's how we were taught to construct a hexagon in High School mechanical drawing class. Thanks Mr. Watson
Mr. Pete. Tabulcain. Whichever you prefer. I have been watching and learning about some machine shop that I am going to be doing soon. Long story short I am going to be creating adapter plate and Crankshaft Adapter for an automotive engine that I am putting into a Tractor. A re-power if you will. I have learned a lot and have chosen to purchase a really neat Craftsman 8 " Rotary table with adjustable X & Y axis pretty much making a drill press into a small Mill. Have you made any video's using something like this ?
And another question. How do you measure for the T-nuts for the Rotary Table ? Looking at E-bay there is Metric Standard , and I am not quite sure how they get the size, Like if it's a 5/8 where did they take the measurement at ? Mine didn't come with any and not sure if a place like Fastenal would even know what these things are.
those neodymium magnets are the best! I have a medium size cube that has a pull off strength of 132lb on 1/8" thick steel! It is now stuck to my locker and there it remains.
I agree with Mike Horn that the divider method should be very accurate if done properly. Be sure that the dividers are still set to the radius of the circle you are laying the bolt pattern on. You are using the dividers to measure the bottom side of a triangle whose other 2 sides are the radii of the circle which meet in the center of that circle forming the apex of the triangle. Since all 3 sides are equal, this makes the triangle equilateral, so all the angles of the triangle are equal at 60 degrees. A full circle is 360 degrees divided by 60 degrees for each triangle makes 6 triangles total in a circle.
The Dumore shows the almost ubiquitous "arc of shame" on the table. I've seen these devices used mostly in drilling holes in printed circuit boards.
Hi mrpete...would it not be possible to perhaps fill in the holes with weld or braze on the platter of your Dumore drill press, then machine the face? Love your videos by the way. Thanks for posting.
Yes. Thanks for watching.
Friggen Beautiful! Thxs!
drawing a 6 whole pattern with the compass method as demonstrated at the beginning of the vid, this method isn't inaccurate at all. It's common practice since centuries and it's accuracy is proved mathematically. The reasons why the sixth and last "compass stroke" 6 doesn't match the starting point are either that the pencil insert needs to be sharpened or the compass itself is worn with some play or that the compass isn't operated accurate enough.
+Mike Horn nope, pi is 3.14 not 3! so its not a problem with the pencil
THANK YOU...for sharing.
Seems like you could just mill a new table for that little Dumore press? It looks like a hunk of aluminum, and we've certainly seen you do that before. You could also run a bead with a TIG welder as Duncan suggested below, then grind or mill it flat.
+Tom B Good idea-thanks
You can buy lithium ion rechargeable torches these days. I dont deal with batteries anymore. Good video though.
I sure do hate batteries
LED's are awesome.
another interesting video we were taught lay out like that but the kids of today will have an apps for it
Thanks Lyle anther great lesson
Great Video, that drill reminds me of the dentist
+Vince o brien Thanks for watching
perhaps one could make replaceable brass/copper "faces" or "sleeves" for such a steel magnifying hammer?
Great Video
thanks mr pete
I didn't know what you meant by bolt circles, we call it a PCD (pitch circle diameter)
If you ever spring for a rechargeable Maglight with LED's you will never go back to the Yellow Industrial Grade Lights. The Maglight definitely is magnitudes brighter and carries for long distances. Just ask a Law Enforcement Officer.
Many LEOs ditched their Maglites for Streamlights. I'm am aircraft mechanic and if someone gave me a Maglite I'd give it away. I have three Streamlight LED Stingers. LED headlamps blow away flashlights for machinist work for one simple reason. A flashlight requires a hand to hold it. An LED headlamp puts light on the work leaving hands free.
I have another question for you. I am watching this video looking at you Center Finder you are using at time number 3:27. I was wondering what type it is because I would like to purchase one like it.
Thanks very easy to use
How to do a bolt circle in a pc. 32 in. OD in a small mill. Bridgeport. The. Y moves only 12in. Moving the head. And .....
55 hrs may be about right. I left one on overnight and it was still going the next day
Could you put it in a 3 jaw chuck on the lathe and scribe three lines with the tool after having plumbed the jaws in the up position, then plumbing again in the down position and scribing again?
That would be only semi-accurate
Based on it's principle this method for sure isn't the most accurate, however even with the compass you shall normally get a much closer result than what you present in the very beginning. If the deviation is really that big, then you have either a compass which isn't rigid enoug or you've done some operational mistakes.
And the little extra uncertainty in your compass circumference is explained by pi
perfect vidio myself is the rotary table. I do have dro's but its easier...
sam good job lylel
just look up the magic numbers from page 75 in The Machinery's Handbook. Good for 3 to 194 spaces. My copy is the twentieth edition. My eyes are getting old, may have to order a new copy in large print or a CD but a CD is hard to read in bed!
good stuff !!!
why so much trouble to determine only 6 holes? If you determined your center hole, take a compass, make a quarter circle on the diameter, from that point you cross that quarter circle and you have a 60° angle, make another straight line through it, and then you can measure the distance with your compass from both diameters crossing the outline, and draw 6 equal length crosssections for all 6 holes. I would even do it on paper just a tiny bit smaller, glue it on, then make your center punch, and just draw, so you can make mistakes, but you'll always have the same center hole.
I like Rayovac batteries, I think they're almost as good as Duracell but cost much less. I think mag-lite makes the best flashlight, you can get the 2D led for around $25, costs more than your Rayovac but excellent quality, and I think they're still made here in the USA. Great video as always!!
Maglites were good 20 years ago because the competition hadn't caught up. They're junk by comparison today. Pelican make excellent lights using modern plastics (handy doing electrical work where a Maglite could short!). Streamlight make superb rechargeables if you have more money. I get better results for less money over time buying quality. For work lights it's hard to beat an LED headlamp because wasting a hand holding a flashlight is awkward on a good day. Any LED headlamp with rechargeable batteries and decent customer ratings will do. I wear them even in well lit rooms when doing precise work. About 20 bucks online from the usual sources.
excellent
I grew up with very dim flashlights in Alaska. I got used to letting my eyes adjust to the dark. Now when you are mining and a grizzly smacks your tent the person next too you blinds you with the new super bright flashlight and you run out side and now the bear can see you and you can't see it so I still like dim light when fighting bears at night. And the bears don't stare at the bright lights ether like they do with old dim lights they learn to sneak around the light and make it much harder too know were they are and when you are in the woods at night with a pissed grizzly I rather see the eyes then hear blobbering growls of a devil tough talking beast. Last year I had a grizzly brake trees and talk toughs for 4+ hours and it sound like playing a record backwards and the growls make you feel real small when you see eyes 14feet in the air. ps I never saw the bear could have been Sasquatch hahah
All of my flashlights when I was a boy were just a dim yellow glow. I could barely see the Sasquatch.
That wasn't a centre punch you were using, it was a prick punch. That's correct practice of course, the less than 60 degree point of a prick punch being followed up with by the greater than 80 degree point of a centre punch. The aim in any case being to have a divot larger than the chisel length of the drill you're going to use.
Mr Pete,
You don't have the guard on your cameron!!!
7 feet is the height wives drop their husbands from.
that compass method should be spot on circumference divided by 6, should be very accurate but you made a mess of it, easier way any cad programme, draw , print, lay paper on the metal
I don't think he 'made a mess of it', he did not adjust for the error in the divider spread which for this 6 hole layout would be 1/6 of the error. Then run it again and you should be very close if not right on.
Do it a third time if you are still off but remember only adjust by 1/N th the error where N equals the number of holes drilled.
Borrowed phone
That's using ole bean shame more people don't that sort thing learning something new every day still
To set your dividers SMALL TABLE UP TO 12 HOLES at bottom
The correct way to work out the distance between the holes (Cord) in the case of seven holes 360/7 = 51.42657143 Deg
Then 51.426571243/2 = 25.71428571 then find the SIN of 25.71428571 on your calculator
which is SIN(25.71428571) = 0.43388374 All you do is multiply .43388374 by the pitch circle diameter you require
TABLE 5 dec places (rounded up) Mutiply PCD by number below
3 holes = .86603 4 holes=.70711 5 holes=.58779 6 holes = .5 7 holes =.43388
8 holes = .38268 9 holes =.34202 10 holes =.30902 11 holes =.28173 12 holes = .25882
Thanks John
mrpete222 n
Sometimes you sound like Jimmy Stewart the actor
I want to see an uneven number like a 5 hole. Was the flashlight made in USA? I like the Mag Lite www.rei.com/product/870252/maglite-xl200-led-flashlight#tab-specs is 172 lumens.
This method clearly has to be very inaccurate. There is a better method using the math to set the dividers.
If pi was 3, the mthod would be perfect, but it is as we all know pi= 3.1416 and that .1416 (rounded) is the error.
Correction: Multiply the diameter of the first circle times pi and you'll end up with the circumference of that circle.
Divide that by the number of holes you want (6 in this case) and you'll end up with an odd but very correct length.
Set your dividers to that length and start at any point like shown in the video.
Regards
Incorrect. This will give you the arc length. But dividers measure a straight line. You actually want to calculate the side length of the regular polygon circumscribed by the circle, which is given by 2 R sin(pi/n) (in radians).
Rubbish. You are trying to mark the vertices of a regular hexagon. This is formed by six equilateral triangles, each of which has two sides that are obviously radii of the circle and whose third side lies on the circle. The third side should clearly also be the same length.
The error is caused by leaning the pair of compasses over at different angles, drawing with different points on the pencil lead.
My "Rubbish" relates to the first comment!