# Hole layout 101



## Tin Falcon (Jan 28, 2013)

many new folks struggle with accurate hole layout. 

For those who have cnc or a Digital Read out DRO simply put in the numbers and check hole locations after a quick peck into the part. but even with dro or cnc a good layout can prevent errors. 
there are varied ways to lay out parts the army TC 9-524 covers basic layout. as does  the MIT video series. here is how I  do a basic hole layout. start with a squared up piece . you NEED two finished edges that are perpendicular (square) to each other.  use a poster marker to dye the part.






 scribe  lines with one of these. 




sitting on a granite surface plate and resting against





Once all lines are scribed  use an optical center punch to punch centers of the holes. 




Above photo grizzly tools
Then center punch with one of these:





photo HF tools

Then drill with a thin drill bit like 1/16 this will follow the punch mark. then with a spot drill . the a pilot drill and finish drill . 
Hope this helps. 


for bolt circles I like a 6 hole cirlce it so happens that the radius of the circle and the cord distance between hols is the same. 
or you can use the above method to lay out after converting from polar to rectangular coordinates. This can be done with math or consuting the machinery handbook.
Hope this helps
 tin
And other fell free to add your favorite method .


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## Omnimill (Jan 29, 2013)

I read a very good article many years ago that dealt with hole accuracy. In short, even if your marking out is very good and you drill carefully often the hole still ends up in the wrong place! Not so noticeable with small holes but large diameter holes, especially a line of them can look really bad. The authors answer was what he called "boxing". Basically he marked and centre punched where the hole needed to be then accurately scribed a box around it that should enclose it. If the hole started to wander as you go through with successive drills you could see it and take remedial action - worse case was to use a file!
If you are drilling by hand it's a technique worth considering.


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## Herbiev (Jan 29, 2013)

The optical centre punch seems like a great idea. What is the best one to get please ?


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## Tin Falcon (Jan 29, 2013)

> The optical centre punch seems like a great idea. What is the best one to get please ?


The one pictured is from grizzly tools . I purchased one from enco Mark-on brand  IIRC made under licence by pc tools. I laso made one. veritas tools (woodworking tools) in canada sells a nice one. 
mine has only one punch and lens. 
Tin


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## goldstar31 (Jan 29, 2013)

Omnimill said:


> I read a very good article many years ago that dealt with hole accuracy. In short, even if your marking out is very good and you drill carefully often the hole still ends up in the wrong place! Not so noticeable with small holes but large diameter holes, especially a line of them can look really bad. The authors answer was what he called "boxing". Basically he marked and centre punched where the hole needed to be then accurately scribed a box around it that should enclose it. If the hole started to wander as you go through with successive drills you could see it and take remedial action - worse case was to use a file!
> If you are drilling by hand it's a technique worth considering.


 
I'm suggesting that this was Tom Walshaw AKA Tubal Cain but George Thomas also went into this thoroughly.

One doesn't play with centre drills to start holes  in the best circles:hDe:


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## Herbiev (Jan 29, 2013)

Thanks Tin. Roll on pension day.


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## MuellerNick (Jan 29, 2013)

That's how I was taught and I stick to it, because it works:

Scribe the crossing lines. With a sharp center punch*) make a light punch. Check and correct if necessary. Correcting should not be necessary, because you can *feel* where the two lines meet. But that requires a sharp punch.
Drill with say 23 mm (if that isn't to big a hole, dummy!). Measure. If need, correct with filing*)
Increase drills until you are at the desired size, maybe correcting in between.

While drilling, rotate work every once by about 90°. This reduces wandering of the drill.

If you need to make precise work, you have to *start* precisely. Lower the drill into the punched location and watch wether it bends left/right or back/forth. You'll have to rotate the drill to see that bending better (you'll learn when you try it). Align vise accordingly. You will never get straight bores if you ignore this initial step.


*) Center punch:
You only need one. The cone has at about 70°80° included angle. Keep it sharp by grinding lengthwise (forget about oil stones).

*) Correcting
If the hole is off by say 0.05 mm in one direction, file the hole oval into this direction, making it bigger by twice the error (0.1 mm).

Center drills are for the lathe, spot drills for the mill. They have nothing to do with drilling to a scribed and punched location.


Nick


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## gus (Jan 29, 2013)

goldstar31 said:


> I'm suggesting that this was Tom Walshaw AKA Tubal Cain but George Thomas also went into this thoroughly.
> 
> One doesn't play with centre drills to start holes  in the best circles:hDe:



Hi Big Brother,

Gus with you but may I add on.I have no DRO. I use a Japanese 150mm Steel Ruler and Starrett Scriber and a Cheapo Prick Punch and do it the TubalCain USA method,using clockmaker's finger drill from 1.5mm 2.5mm and 4mm if required to spot on starter holes so that drill will not wander off. Ever since all the holes been spot on.I use box when necessary with critical holes.
Looking for suppliers who will ship spotting drils to Singapore.


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## goldstar31 (Jan 29, 2013)

The issue is really that you are not using an Archimedes pin drill in conjuction with a watchmakers loup.

OK it's old hat stuff but I have a set of loups of various powers, the perspex.plexiglass thing, the surgeon's binoculars and--- a couple of microscopes. One is a proper brass affair whilst the other is from a children's toy science set.
The best lathes should have a plsce for the microscope. I always use a surgeon's pair of binoculars for setting my verniers. Nice having a daughter who has a Masters in Dentistry and a son in law who is a senior consultant in heart surgery. 

Cheers

Norm- the Happy Wanderer


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## ShopShoe (Jan 29, 2013)

Sorry, slight wobble off-topic.

This made me remember that there's a product for magnified viewing of marked location, then punching.

http://www.starrett.com/metrology/p...ols/Precision-Shop-Tools/Other-Shop-Tools/815

Interesting idea. I don't have one, probably won't get one.

I do have several magnifiers, loupes, magni-visor. Want a microscopesomeday.

--shopShoe


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## MuellerNick (Jan 29, 2013)

> I use a Japanese 150mm Steel Ruler [snip] Ever since all the holes been spot on.



I think, you do have a different definition of "spot on". With a ruler, I'd say you'll be always "quite off" (at least to my definition).
You need a height gauge (first post, first picture) to get precise work.

Why not use center drills or spot drills? They do not bend, they are designed to be rigid. When drilling to scribed lines, you want a flexible drill to see wether you are spot on or not.



Nick


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## steamdoug (Jan 29, 2013)

I have a little trick I use if at the start of drilling the hole is not quite spot on or has started to wander i have some very small end mills and I take the closest to the size of the hole I am drilling and remove just enough material so that the hole acts as a guide for the drill, you can remove material from the edge of the mis drilled hole with the end mill to re align it and hopefully get a truer hole. I haven't tried this with anything over 4mm but I think anything larger is easy to spot and rectify before needing to use end mills
Doug.


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## kvom (Jan 29, 2013)

I am wondering how many of us make models where hole location tolerance is less than .005".  Using the basic scribing and punching techniques described here should result in at least that degree of accurancy, esp. as drills are not particularly precise instruments themselves.

I know that 99% of the holes I need to drill are either tapped holes or are clearance holes for screws, and a small deviation in a tapped hole's location can be accounted for by adjusting the clearance hole.


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## Tin Falcon (Jan 29, 2013)

http://www.mwdropbox.com/tutorials/ARMY-TC-9-524/ch1.pdf
Tin


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## gus (Jan 29, 2013)

goldstar31 said:


> The issue is really that you are not using an Archimedes pin drill in conjuction with a watchmakers loup.
> 
> OK it's old hat stuff but I have a set of loups of various powers, the perspex.plexiglass thing, the surgeon's binoculars and--- a couple of microscopes. One is a proper brass affair whilst the other is from a children's toy science set.
> The best lathes should have a plsce for the microscope. I always use a surgeon's pair of binoculars for setting my verniers. Nice having a daughter who has a Masters in Dentistry and a son in law who is a senior consultant in heart surgery.
> ...




Hi Big Bro.Norman,

Where can I buy WatchMaker's Loup. Using my fingers to twirl 3mm drill is tedious. 

Hole Drilling Topic getting hot.

After finishing Trade School,went to Metal Box as a Trainee. Was surprised to see master fitters using "Box" to drill holes. We were taught using O and cross hair in Trade School.

Getting a bit hot today with my Made In China Ceiling Fan at full blast.:fan::fan::fan::fan:


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## johnmcc69 (Jan 29, 2013)

Great info there Tin.
Thats how we learned it in "Tech School" also, never failed me, just my eyes.

Another great tool for aligning a machine spindle to a scribed
line is a ""Wiggler", it's kind of a "floating" scriber point chucked
in a machine spindle. You set it running "true" with your thumb nail, (with
the spindle turning) & position the X/Y location under the point.
Used pretty often in mill machine set ups, & actually pretty darn accurate.

John


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## Alchymist (Jan 29, 2013)

http://www.gadgetbuilder.com/OpticalPunch.html

http://qrp.webhop.net/Metal_Bashing/Optical_Center_Punch/Optical_Center_Punch_Tool.html


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## goldstar31 (Jan 30, 2013)

Hi Gus!

First --'Metal Box' Long time ago, one of my mates was Chief Buyer in UK and went to India.
          We used to go white water canoeing! 
And to loups and things. I would be looking at some UK company like Proops Online. They sell nice little 'goodies' such as loups, archimedes drills and tool holding stuff. It isn't the best but it it is there-- and is cheap. We talk in big terms of about this and that when cheap little bits of tools are more than enough to have and use.

And so, my friend, to the Year of the Snake. Not long now.I was wanting to go out to HongKong again but my wife isn't fit enough. So I am off to Newcastle's Chinatown with 203 Masonic brothers to feed the dragon. Too much food, too much whisky!
Kng Hai Fat Chow in the Year of the Snake

Norman


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## Tin Falcon (Jan 30, 2013)

Gus ENCO tools in the US IIRC has loupes the other hand tool is an optical comparitor  . I used a hand held pocket one when I worked in the printing trade. handy for measuring layout errors small radii etc. Another tool on my buy someday list.

 John good point on the wiggler.


Tin


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## gus (Jan 31, 2013)

Hi Tin Falcon,
Spotting Drill & Loupes.Enco does not ship to Singapore.Will try other sources.My eyesight is not best at 70.Only some days I am good at popping centres spot on cross hair. Will need to buy the optical aid to pop centres.Got profits coming in about a month to take care of new requisition.
Tried using the conventional Mag Glass which ended up needing three hands .Ha Ha.
One more week to go & hit TokyuHands,Osaka,Japan with my better half.

Will keep u posted in Osaka.Still trying to locate other machinist shops but no avail.There are some on the net but only in Nippon-Go,no English.Fishing Equipment Shops are aplenty.

Best Regards

Gus Teng.


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## jack620 (Feb 2, 2013)

gus said:


> Looking for suppliers who will ship spotting drils to Singapore.



Gus,
Chan Man Lee in Rowell Rd sells them.  I bought an Australian made P&N 90 degree 6mm spotting drill for Sing$9.00 last week.


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## Tin Falcon (Feb 3, 2013)

Keep in mind there are various layout methods and tools. 

There is semi precision layout that typically give a result of +- 1/64 of an inch or 0.015inches.  On a drawing set specified in fractional inches +- 1/64 is the normal tolerance.  that is where you use the 6" rule and calipers to scribe lines. But this may not really be good enough.The methods I described should give a +- 0.002 result.   

About 12 years ago I started working in a professional model shop.  I was given a simple part to make  the print was in fractional inches so that told me the tolerance was +- 1/64 I made the parts and was told they were not good enough. the foreman remade them . later I had to do a bolt circle I calculated the coordinate to use the dro  the foreman was surprised because the guys had always layed out the holes with dividers. He was happy that I was using a more accurate method. 

I am a machinist not a mind reader. The good thing is in the home shop you decide what is good enough. You can decide what methods to use and what results you need.
Tin


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## old-and-broken (Feb 3, 2013)

www.books.google.com/books?id=oV4PAQAAIAAJ&pg=1


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## Tin Falcon (Feb 3, 2013)

Nice one. 
Tin


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## jack620 (Feb 3, 2013)

How do I download the book?  There's no Download link.


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## Tin Falcon (Feb 3, 2013)

click on the link you will see a little gear icon on the right upper part of the screen click on the down arrow next to it. then click on download pdf it will take you to another screen type in the squiggly letters in the block and click on the submit button.
Tin


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## gus (Feb 3, 2013)

jack620 said:


> Gus,
> Chan Man Lee in Rowell Rd sells them.  I bought an Australian made P&N 90 degree 6mm spotting drill for Sing$9.00 last week.



Thanks Jack,

Will drop by Rowell Rd to look see. The trouble with local tooling suppliers,we seem to have specialists---pressure/temperature gages only, bearings and oil seals only,power tools only,bolts and nuts only. Tooling shops in China have a very wide range of tools. Will call a CNC Machineshop mate for leads to some supermarket type.Keep you informed.



Bought one 3/16 from Ebay which cost me US$7.22 w/o DHL added on.


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## goldstar31 (Feb 4, 2013)

Gus,

What you really want is something called a 'Spear point drill' as old as Archimedes or older.

One simply knocks them up from scratch. If you eyesight holds up- make them from darning  or even sewing needles

Cheers

N


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## gus (Feb 5, 2013)

Hi Norman,
Seen this as a carpenter's bow driven drill. Please advise source of drawings or sketches.

Or will a very sharp pointed spade drill do the job? 

Come 7th Feb 2013 ,Gus will take his better half 68 young lady to Osaka. Both will be at TokyuHands window shopping. Will need a tight hold on Credit Car.Too many goodies to look at and too tempting.


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## goldstar31 (Feb 6, 2013)

Hi Gus
             these tiny little drills are tiny little copies of the old carpenters much bigger ones.
 You can only get one cutting edge on each side because they are too small. Probably the best source is reading old books on clock and watchmaking.

Incidentally, Kung Hay Fat Choy in the Year of the Snake.

Enjoy your holidays. I'm starting mine at the weekend

Norman


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## gus (Feb 6, 2013)

goldstar31 said:


> Hi Gus
> these tiny little drills are tiny little copies of the old carpenters much bigger ones.
> You can only get one cutting edge on each side because they are too small. Probably the best source is reading old books on clock and watchmaking.
> 
> ...



Hi Norman,
To make it authentic,Gus will use Chinese Text for the CNYear Greeeting.
&#24685;&#21916;&#21457;&#36130;&#65281;&#65281;&#65281;&#65281; KungHayFattChoy&#12290;

Will go into clock making webs to look for spear drill. Seen my uncles next door using it. These old carpenters just won't touch a power drill but their skill is first class. All dead by now.Did picked up some skills from them.Nobody will pay too much for a handcrafted Camphor Wood Chest and Cabinet.:wall::wall:
Gus is not a great carpenter.You cannot be when you buy "cut to size" plywood and knocked together with power drill,power screw driver and square and cover up the flaws with Formica. Ikea ckd furniture is too expensive & flimsy. Build two three drawer locker for a song.:
Will be window shopping a TokyuHands,Osaka,Japan.A handyman's paradise.
No worry .Gus will not overspend.

Getting very hot and humid now.:fan::fan::fan:


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## goldstar31 (Feb 7, 2013)

Hi Gus,
           drop me a note of your proper e-mail address and I will copy the bit from Ian Bradley's The Drilling Machine.

Meantime- I'm off to feed the Dragon.

Cheers

Norman


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## gus (Feb 12, 2013)

Alchymist said:


> http://www.gadgetbuilder.com/OpticalPunch.html
> 
> http://qrp.webhop.net/Metal_Bashing/Optical_Center_Punch/Optical_Center_Punch_Tool.html



Hi Alchymist,

Plan to make one to pop crtical centers. The normal centres will stay by eyeball. Thanks for the link.

Gus Teng,Just got back from freezing cold :wall::wall:9---2 C Osaka,Japan back to nice & warm 26 C Singapore.


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