A while back I was using a dial thickness gauge for something totally unrelated to bowmaking, and facilitating its use brought to mind when I used a plastic dial caliper, sliding it down my bow's limbs, watching the movement of the needle in the dial to reveal limb taper.
When I dragged the tool from dips to tips, as long as the needle kept sweeping counterclockwise, regardless, or in spite of, the actual number per/thousanths, I knew the limb was reducing in thickness in that direction. If the needle ever stopped, or went clockwise, I looked to the design, cause, and made adjustments as needed. As I grew more accustomed, I just kind of watched the dial in my periferal vision as I dragged it down the limb. Abrupt jumps in needle position are picked up in periferal and could be simply due to a knot's raising on the bow's back or some-such, but beyond that... I could simply 'watch' for a deviant from the consistant counterclockwise 'swipe' of the needle which revealed my taper. It's a dynamic sort of gauging, ya know what I mean?
On most bows, we can actually use this to be quite precise in thickness determination/judgements... Don't worry cuz they're just 'wood bows'? guess again. Even in wood... some things can be surprisingly consistant/dependable... thank goodness... :)
Many years ago I found my plastic dial calper to slide much more easily down the limb than my metal one. So I began kickin some things around.... the thickness gauge seemed like something I could use... IF...
So I searched and ultimately found thickness gauges for sale, but, for $50-$500? Eh... no. I don't think so... additionally there was always an issue with them when it came to applying them to wooden bows... cost, bottom anvil material or shape, sharp 'catchy' edges, etc. I wanted to use my taper gauge throughout the tillering process, up to, and including final tillering. So it had to be 'gentle' to the wood.
Working to avoid my propensity to make things more complicated, all that was ultimately needed was an idicator gauge ($19.99) and a small piece of scrap hardwood. The bottom 'anvil' was simply an integral part of the wood 'frame', and radiused with files and sandpaper so that it glided down the bow's belly unobstructed. No bearings, rollers, felt or mole skin required :^)
My Harbor Freight gauge had a stem dia. of 3/8", so that's the size of the hole I drilled in the top of the red oak piece. It fit snugly no matter how many times I removed and reinstalled it.
(http://img.photobucket.com/albums/v312/Jeff_Durnell/Thickness%20Gauge/ThicknessGauge1_zps8903cf96.jpg)
(http://img.photobucket.com/albums/v312/Jeff_Durnell/Thickness%20Gauge/ThicknessGauge2_zps3a26852d.jpg)
Stuff the dial indicator into the oak 'C' frame's 3/8" hole and away ya go......
(http://img.photobucket.com/albums/v312/Jeff_Durnell/Thickness%20Gauge/ThicknessGauge3_zpsd249b30e.jpg)
very cool.
Slide it down the limb... watch the needle..
cool idea.
They do make roller inserts and more rounded tips for the pins as well.
I like it!
Slide it down the limb..... up or down... works either way...
(http://img.photobucket.com/albums/v312/Jeff_Durnell/Thickness%20Gauge/ThicknessGauge4_zpsb7834e71.jpg)
Great idea! Thanks for sharing it.
Pretty slick, Jeffro..
Yeah, I thought about the roller tip. It worked good on this bow without it, but it was already fairly smooth. It rolled fine over the scratches the #50 left behind. The bigger roller might come in handy when the bow is rough with coarse rasp marks.
I also thought about putting a roller on the bottom of the tool, but it worked well by just radiusing the part that rides against the bow.
I like it. :)
Clever idea.
They also make a flattened mushroom head shaped tip that looks promising.
I got one this morning from a machinist pal 'o mine :thumbsup:
(http://img.photobucket.com/albums/v312/Jeff_Durnell/Mobile%20Uploads/20140311_073203_zps616f7bc4.jpg)