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+-- Thread: Double pencil compass? (/showthread.php?tid=7329857)
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Double pencil compass? - jgourlay - 04-29-2017
Do anyone make a compass with two pencils? I'm looking for something where you can set the width between pencils to lay out defined width circular grooves.
RE: Double pencil compass? - jcredding - 04-29-2017
If I'm understanding correctly what you're trying to do, I use the Lee Valley beam compas heads spaced as I want them on one end with pencils installed. On the opposite end run a screw through it (or something else with a sharp point to pivot on), essentially creating a three point beam compass of any length you want.
RE: Double pencil compass? - Boatman53 - 04-29-2017
There are these http://www.starrett.com/metrology/product-detail/85B but I don't think you will like the price. Good thing I got mine a looong time ago. Just replace the two points with pencils.
I use mine a lot.
Jim
RE: Double pencil compass? - teetomterrific - 04-29-2017
For circles 8" or smaller I just draw them on my PC. Print them out on 8.5x11 paper. Spray on some glue lightly on the back. Let the glue mostly dry and then stick on the wood where I want it. After cutting or routing I just peel what's left of the paper off and remove any residual glue with mineral spirits. Works great.
RE: Double pencil compass? - Lynden - 04-30-2017
What size circles will you be drawing? For circles up to 20" in diameter you can use a 6" drafting compass with an extension bar. If you buy an extra extension bar you will have two lead holders which you can position on the bar to draw concentric circles.
https://www.amazon.com/Alvin-975VK-Professional-Jet-Bow-Compass/dp/B000HEQNOQ/ref=pd_sbs_201_2?_encoding=UTF8&pd_rd_i=B000HEQNOQ&pd_rd_r=R9RTXB14Y2EPSQ62RMCQ&pd_rd_w=TdTzB&pd_rd_wg=VwyHB&psc=1&refRID=R9RTXB14Y2EPSQ62RMCQ -- more expensive brands (i.e. Staedtler) are available
https://www.amazon.com/Alvin-Bow-Beam-Extension-R18/dp/B001DIDZIW/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1493525828&sr=1-1-catcorr&keywords=Compass+Extension+Bar
compass with extension bar
Longer extension bars may be available which would allow you to draw larger circles. Also, compasses larger than 6" may be available.
RE: Double pencil compass? - mike4244 - 04-30-2017
I suppose it would be a simple task to make one. A 3/4" x 3/4" piece of wood with holes bored down the center at various intervals. Pencils placed in holes and held with a set screw. Another way would be to partially split the stock with a band saw and tighten the holes by means of clamp or thru bolt. My uncle was a stair builder and used a similar tool to layout the stringers. He did not use pencils but used 1/4" steel rods that were turned to a point. The stock was steel too. The stock looked similar to flaring tool for tubing. Split in half and had a bolt and wing nut at each end.
mike
RE: Double pencil compass? - AHill - 05-01-2017
You're probably wanting to mark both sides of the groove at the same time. I'd just just my regular compass, draw the first circle, then reset the radius for the second circle and draw again. I don't think a beam compass will handle widths of less than 1/2" or so. There are some inlay working tools that allow you to mark a consistent radius, but usually for string inlay.
RE: Double pencil compass? - blackhat - 05-04-2017
3 small pieces of scrap lumber, 1 nail, 3 x 1/4" bolts and a piece of T track. Build time less than an hour. Easy peasey.
RE: Double pencil compass? - museumguy - 05-05-2017
this is my go to set https://www.amazon.com/General-Tools-523-Adjustable-Trammels/dp/B00004T7R5/ref=sr_1_1?ie=UTF8&qid=1494027922&sr=8-1&keywords=trammel+points
you replace the metal points with 1 or 2 pencils, works great.
RE: Double pencil compass? - Steve N - 05-07-2017
(04-29-2017, 02:17 PM)jcredding Wrote: I use the Lee Valley beam compas heads spaced as I want them on one end with pencils installed.
Eggzactly
![[Image: beam_strong_style_color_b82220_compass_strong_heads.jpg]](http://img.chinalane.org/pic/z2b0b8ea-300x300-0/beam_strong_style_color_b82220_compass_strong_heads.jpg)