Nice video - thanks Lee. For those wondering how to remember the formula 2 years from now when you need it, you can find it in Machinery's Handbook. It's in the chapter on Math in the section on Geometry in the subsection on Regular Polygons in a sub-subsection called Formulas for Circular Segments. That happens to be page 77 in the 29'th edition, but the page number will vary in other editions. Also note that the formula in Machinery's Handbook is for the radius of the circle while Lee's formula is for the diameter.

Yes please for manual BHP. Thanks for these videos

I really appreciate that you showed the steps to input the numbers into the calculator!🛫😁

Great video Lee! I ran machines for years that had dro's but no other function but location. One didn't even have absolute function. When dro's started getting all the functions I'd already moved on to NC machines. When I got my machines for my home shop I bit the bullet and installed the best dro's I could buy on my mill and lathe. Pricey but makes my hobby so much more enjoyable. Great tutorial on using one of the dro features. Even though I know how to do many of the things you video I still watch, because your ways of explaining your process is so good! I use many of your examples when showing my kids and now grand kids how to do things. Some people are better teachers than others! Thanks for your time and sharing, Lee! 👍😎✌️

Nothing is perfect, just a degree of accuracy lol, great video my friend.

Great explanation Lee. I also would like to see the caliper explanation. Thank you.

Thankyou Lee, l found this both entertaining, and very informative. Thanks again

Wow !!! What a lifesaver!! I'm currently a new CAD greenie, and I have to make a dxf drawing from a vintage 1934 Bugatti Type 57 Stelvia steering wheel. IT has a hole in the center for the horn button surrounded by six bolt holes. You have just pointed me down the right road to get that bolt-hole pattern correct. Thank you SO MUCH.

Please do more on the manual way of doing a hole pattern. This one was very informative but I don't have a DRO.

exelent video lee really enjoyed it and learned what i was always wondering on how to layout bolt holes. yes and please show how to layout bolt holes with dividers that would be very good to know. thumbs up. i have a dro on my 9x49 atrump mill.

I'd like to see the other method for laying out a bhp.

Another method is to draw a shape (pentagon in this case) in any CAD program with a side the equals hole distance. Measure in CAD the distance from center to any vertex and you are done. It is quicker than typing numbers into the calculator. As a bonus you can print the pattern then glue it to material and drill decent hole pattern on a drill press.

I’m a mathtard when it comes to stuff like this, but your explanation was very helpful, in all honesty I can use all the helpful hints that I can get.

It’s only perfect but it will have to do. Thanks for the great review on BCDs with the DRO. First time I ever used mine on my Precision Mathew’s mill I was ecstatic with the results. I had to match a bolt pattern on a fly wheel on a small marine diesel to make a holding fixture to remove the attachment hardware the fit was perfect and it was so easy after determining the diameter .

You had me at math! I appreciate you sharing the formula with us uninitiated

Lee any information you wish to pass along is fine with me good refresher on the bolt hole on the D R O so a paper lay out one would come in handy as well thanks great videos all of them have done a catch up on them all thanks Lee

As always, excellent presentation of very helpful techniques-Thank you very much ✅👍

I just found your video. I really like watching and listening to you. I wish my father had your skills.

Great video. Its not often that I learn something about my Iphone while I am watching a machining video. Great explanation of the trig involved in determining the diameter of the bolt hole pattern. Thanks for taking the time to make the video.

Thank you for the simple explanation

Yes, for those of us that do not have a mill. Please layout the bolt hole pattern using a pair of dividers.

Very helpful guide. Thanks for sharing this procedure. New subscriber.

I like the change gear wall. Never thought about that one. Thanks for the visual tip.

I would like to see it. I would also like to learn more about the DRO's functions. You do a good job explaining in terms I understand. God Bliss!

Thank you for this video Lee, I appreciate your clearly stated presentation. The DRO lesson was also much appreciated and I would welcome your suggestion of a video about a non-DRO layout.

Hi Lee, I don't have a mill but do occasionally need to make a bolt hole pattern. This is helpful. Also, I know you showed it last week too, but showing how to get the scientific functions for the cell phone calculator, was great tip. Very simple but something I did not know. Thanks for the video! -mike

Great video! I thought this would be much more complicated to learn, but you explained it clearly and made it look easy. Thank you. I would like to see a video using the calipers. That's the way I would have to do it. 👍

Lee, I grew up using copper sulphate as marking dye and a good lathe was one that didn't have chipped teeth on the lead screw. I enjoyed watching your video and look forward to watching others. Terry from Australia.

All clear as day, except the sin information.. not sure if that’s a standard number used across all hole patterns or was just for this particular pattern. But thanks for the lesson. I’ve always sucked at math, always found crud way’s around it to fabricate whatever I was working on. But now that I’m older I’m trying to get more accurate and learn the proper ways for machining the correct way. Thanks for time.

That was really helpful. Thank you Sir!

Great video! I have learned a lot from your channel! I'm new to the hobby and you have helped me trendously! Thanks!

Lee, Very good explanation. I have a dro on my mill, but haven't used the bolt hole pattern feature in quite a while. Great refresher...

Thank you sir, this helped explain a lot for me.

A quick quality control check of the bolt pattern of a hub would be, using calipers , to measure the distance of each bolt hole to the edge of the large centre hub hole and then the distance between each bolt hole, sequentially. . Not as an absolute, but as a comparator within a defined tolerance. Just as a check to see how 'perfect' the existing bolt hole pattern is.

Thanks for the trig lesson every little bit of knowledge is very valuable. So you noticed I had my zero angle on the other end of the mill bed. That comes with a story. When I got my mill it arrived with a broken "X" axis dro scale. The fine folks at Precison Matthews had a new one shipped from China. This took about 3 weeks and when I got it I forgot which way it was mounted and put it on backwards. This worked just fine anyway and I did not discover it until I was trying to make a radius with the dro. Strangely the left curve went right and the right curve went left and they were upside down. This gave me a clue that the "X" scale was backwards. Slow thinker that I am it took me a few days to figure that out. Now my zero angle is on the same side as yours and all of the radius formulas work as planned. Keep on keeping on.

Thank you ! This helped me so much !

Great video. Excellent instructions. Thank you for sharing.

Love these instructional videos

Thank you Sir it certainly helps reboot the memory. I did forget that some time ago.

Great vid but I do have a question. In your formula you had written bolt hole center distance but you appeared to be measuring the edge to edge distance with your dig calipers. Was there something you did to compensate for that? Am I missing something?

Hey Lee, Your channel name speaks for itself. Subbed.

I always enjoy your videos. Thank you. Tom

I just used this function on the dro yesterday to drill and tap the bolt holes for the cylinder head on a PM research steam engine.

Great video 😊. Very well explained and executed 👍😁👍.

Seems that marking the center would also be critical. Would be easier while already set up for drilling I think.

Excellent video

Very informative video I would much like to see the manual layout procedure

Nice explanation

Interesting...many thanks...

Thanks for the video,,

Lee thanks for the math lesson.

Outstanding Thank you

Well explained 👍👍👍

all i need is a piece of paper and a small hamer with a rounded end on one side ,place the paper on the flange and trace the id and od and the holes with the rounded end of the hamer than plavce the paper on the workpiece and your set to dril the holes , no mesuring no formulas no calculations ,no wurys ,greets from a retyerd ships engineer

When you run your tap, how do you time the amount of speed on the quill down feed? I mean the quill doesn't free slide down if you pull on it, so if the dow. Speed is off won't the tap strip out the hole? I never understood that. On a lathe the tailstock feeds freely toward the workpiece, but that's different than a mill, no?

also you can use a cad program and create a sketch

I did exactly what you did to find the sin of 36 on my iPhone calculator and came up with a totally different number than what you got

Thank you :) You Rock!

This may be a dumb question, I usually hand tap and don’t get why powerfeeding taps in and out doesn’t snap the taps ever, is it because it’s a thin material or a through hole? Sometimes I see people doing with thick stuff in blind holes not using a cnc

Another great video!

got it well done well worth a sub and a like

Enjoyed…nice tutorial

Good video

Good job, but I would like to see the process without the DRO

Good stuff

Great edit Lee, thanks :)

Thanks

Thanks, this really helps

Thanks for sharing 👍

Why do you zero the calipers?

Mr Lee I would love to see laying this out bay hand I do not have a mill

I would like to see it

Yes

More holes make more patterns!

good video..thanks for your time

You are going in the opposite direction how does that work with backlash? Yes I am a math dummy. Next, I don't have a DRO, but enjoyed your video!

Thankyou

👍🏻

Yes I dont have a dro and would be interested in doing a bolt hole pattern with dividers. Interesting video otherwise.

Very interesting video. Thanks. But for me, if I saw right, after you determined the hole diameter you measured from outside of one hole to the opposed out side of the next hole with your calipers. Not the center of each hole. does this still work or did you subtract .250 from you measurement?

I’ve got to get me a dro it’s an incredibly handy tool

Hi Lee. You mentioned Harold At ARW. Could you please let me know what the full channel name is? Thanks

Zero at 3:00 o'clock then counterclockwise is the same as Autocad.

Would you explain "center of the hole" It looked like you were using the distance from outer edge to outer edge of next hole. Mathematically, Is this the same as the center?

👍

TL:DW. Fewer words, more information please