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KB1SYV
04-16-2010, 10:54 PM
Hey Guy's,

I have to make use of drill bit's since I don't have a height gauge. If I have a 1/8" piece of metal how would I mark the two lines(one for each side)? It measured 4/32" and I took 2/32" to be the halfway point. I then used a 1/16" bit to mark a line on each side. Well that didn't come out right. Where is my thinking going astray?

Thanks Everyone.

Jeff

silver_pilate
04-17-2010, 01:04 AM
Easiest way is to go to your drill bit set and pick the 2nd smallest bit down from your steel thickness (if you have a full fractional set). If you're steel is 1/8", use a 3/32" bit. The center for the 1/8" bit will be at about 0.0625". The center for the 3/32" will be at 0.0469". The difference between those will be about 0.015". That will be how far off of center line each mark will be. Mark one side, flip it over, and mark the other side. The total between both lines will be approximately 1/32" or 0.03".

--nathan

Ernie Swanson
04-17-2010, 07:41 AM
I do the same, but remember to color the edge with Dykem blue or a sharpie marker. That way your scribe lines will show up better.

KB1SYV
04-17-2010, 02:55 PM
Thanks Nathan and Ernie. Ernie I can't find any Dykem locally, so I'm using a black sharpie. Nathan, is ther any formula your going by, or just common sense that I'm totally missing?

Jeff

pocomoonskyeyes
04-17-2010, 06:19 PM
Could someone put up pics? I'm totally lost about what you are saying!!

Ernie Swanson
04-17-2010, 07:16 PM
I will post some up tomorrow afternoon, I have a blade I need to mark anyway!!!

KB1SYV
04-17-2010, 08:49 PM
Could someone put up pics? I'm totally lost about what you are saying!!

Sorry, I should've thought of that, because I'm a total visual learner myself. It's just that usually the questions I ask, other people have no interest in, so it's usually only me learning something!

Jeff

silver_pilate
04-17-2010, 09:29 PM
Jeff, there's no real formula, just math. As long as the difference between the stock and the bit size is 1/32" bigger or smaller, when you scribe one line and flip the stock over and scribe the second line, the two lines will be 1/32" (0.03") apart.

Here's a very crude sketch (sorry...I'm no artist ;) ):

http://i121.photobucket.com/albums/o202/maco_man/centerscribing.jpg

You don't even need the 1/8" drill bit center-line. You can just take the 3/32" bit, lay the stock flat, lay the drill bit on its side next to the stock, and use the point to mark a line on the edge of the stock. Now flip over your stock, and run the drill down the edge again, and you'll have two lines, one on either side of center, that are 1/32" apart.

--nathan

KB1SYV
04-17-2010, 09:37 PM
I knew there was an air bubble in my brain!!! It seemed so easy, and I made it so difficult. I'm such a monkey, I guess if I put a banana on the blade, I would of figured it out myself!!!

Thanks Nathan.

Jeff

Fross
04-17-2010, 09:46 PM
For future projects, I suggest you get you a cheap pair of calipers and measure the thickness of your blade, then subtract anywhere from .020 to .050(depending on blade size) from that then divide the remaining number in half... set the caliper to this measurement and then rest one opening on the side of the blade edge and then the other edge onto the edge of the steel dragging it across the edge marking it length ways, do this on both sides and you will be left with exactly .020 in-between the 2 marks. A decent dial caliper or a digital one from Harbor Freight runs pretty cheap, cheaper than a set of decent drill bits.

This is just a tip, I started out using drill bits and as soon as I got a set of calipers, I smacked myself in the head for wrestling with those bits for so long.

silver_pilate
04-17-2010, 09:53 PM
Better than calipers is a height gauge. That's what I use for all my blades now.

--nathan

wdtorque
04-18-2010, 11:01 AM
Nathan, nice picture/diagram, sure explained things pretty well.

Ernie Swanson
04-18-2010, 03:09 PM
Ok here we go:D
In this tutorial I am using a 5/32'' drill bit with 1/8'' stock. My lines are about .035 apart.

Here I have colored the blade with a black sharpie
http://i186.photobucket.com/albums/x124/bigern26/003-27.jpg

Then I lay the blade flat on one side and the drill bit flat on a smooth surface, Here I am using a 12''x12'' granite tile. Then I drag a drill bit down from tip to my choil.
http://i186.photobucket.com/albums/x124/bigern26/004-20.jpg

Leaving a very nice scribe line.
http://i186.photobucket.com/albums/x124/bigern26/005-15.jpg

Then I flip the blade over and drag the bit from the choil to the tip.
http://i186.photobucket.com/albums/x124/bigern26/006-12.jpg

And here is what it should look like with both lines scribed!!
http://i186.photobucket.com/albums/x124/bigern26/007-13.jpg


I hope this help!!
Ernie

pocomoonskyeyes
04-18-2010, 03:21 PM
Okay Ernie, I'm assuming that your drill bit is laying flat on a surface, as is the Blank? Then you are just moving the blade along the drill bit?

Ernie Swanson
04-18-2010, 03:24 PM
Okay Ernie, I'm assuming that your drill bit is laying flat on a surface, as is the Blank? Then you are just moving the blade along the drill bit?

I edited it, Yeah the drill bit and blade are both laying flat on the surface.
I slide the drill bit not the blade.

pocomoonskyeyes
04-18-2010, 04:15 PM
Thanks Ernie!! Now it is all perfectly clear to me.

KB1SYV
04-19-2010, 10:32 AM
Outstanding Nathan and Ernie,

Both of you guy's went out of your way to get the point across!!! I gave the thread a rating so that people could check out a fully illustrated instruction on how to mark the center of the blade. I'm sure that there are more than two people out there who have a similar question.

Thanks again Guy's!!!

Jeff

M. Wohlwend
04-20-2010, 02:07 AM
Better than calipers is a height gauge. That's what I use for all my blades now.

--nathan

Height gauge is best. Place the ricasso area of the knife on a 123 block. Use a flat granite slab for a base. Thie method will catch any warping in the blade. 2thumbs

murphda2
04-20-2010, 07:34 AM
It also would be advisable to use new drill bits if his is the route you are taking. Using an old worn bit could throw your measurement off.

James Terrio
04-20-2010, 08:00 AM
I use an adjustable scribe similar to this one (http://www.usaknifemaker.com/store/knife-scribe-magnum-with-18-carbide-scraper-p-2332.html) to mark edges. They're pricy but work very well and last a long, long time. They're adjustable from a couple thou to a couple inches.

I also use mine to scribe a line in from the spine, on the tang, to help me lay out my pin holes, evenly spaced from the spine. Works even if the spine is curved.

Such a scribe, a basic caliper (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66541), and a small mechanic's square (http://woodworker.com/4-steel-machinist-square-mssu-801-455.asp?search=layout%20squares&searchmode=2), have really helped me a lot. Put 'em on your wish list. :)

KB1SYV
04-21-2010, 06:04 PM
Thank you Murph and James, I just need to set priorities on what I need to spend money on first.

Jeff

James Terrio
04-21-2010, 07:09 PM
I hear ya Jeff, it's taken me about four years to get where I'm at tool-wise, and I'm far from done.

The drill bits will definitely work and you need 'em anyway. Double-use tools are always good!

Ernie Swanson
04-21-2010, 07:46 PM
I am going to be getting a surface plate and a Height gauge real soon.
But yeah my drill bits have came in real handy!!

N.D.
05-10-2010, 12:59 AM
I use an adjustable scribe similar to this one (http://www.usaknifemaker.com/store/knife-scribe-magnum-with-18-carbide-scraper-p-2332.html) to mark edges. They're pricy but work very well and last a long, long time. They're adjustable from a couple thou to a couple inches.

I also use mine to scribe a line in from the spine, on the tang, to help me lay out my pin holes, evenly spaced from the spine. Works even if the spine is curved.

Such a scribe, a basic caliper (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66541), and a small mechanic's square (http://woodworker.com/4-steel-machinist-square-mssu-801-455.asp?search=layout%20squares&searchmode=2), have really helped me a lot. Put 'em on your wish list. :)

Now . . "that marker" . . is the bees knees for sure, thanks for sharing that W us!!! 2thumbs take it 1goodjob1luvsite1nicethread1urock1

Back in the day it was a very common practice for many of the top makers to just eye ball the center line of the blade edge as they were free hand grinding them out.

(that's how I was taught to do it)

A smaller different version of this type of scribe marker was offered back in the day and I really wish I would have had one back then too, it sure would have made life easier!

Thanks big time!

franklin
05-17-2010, 02:55 PM
heres a1.50 hight gadge i made from a wood mortice scribe at least the guy at garage sale called it that then placed it in a sanded flat 2/4