Been mostly reading here as of late....havent posted in a while. Im gearing up to take my first crack at bow building.....glass bows.
Would someone please throw out some recommendations for calipers or mics to measure thickness of lams, glass and total stacks? There are a million different models and they run a HUGE range in price. Don't want to drop $200 on some crazy micrometer that isnt even optimal for the job. So what do you guys use? Make/Model? Thanks for the help!
I use a digital mitutoyo that I acquired for nothing, but I'm told they're expensive. I think canopy boy told me he bought his digital one for a very reasonable price, maybe he'll chime in.
I use a harbor freight 6" digital caliper. $20 and precise enough for bow making (+/-.001)
I use a digital pair I got in the reloading section at one of them big outdoor stores that I got for about $30. They are every bit as accurate as my mitutoyos that don't use in my bow shop because all that dust
Although I have a few different types and brands of calipers and mics, I'm currently using a Mitutoyo digital caliper... because I know where THAT one is :^)
They dont have to be fancy to get the job done. For years I used a cheap plastic dial caliper with no problems.... until Roy spilled a pint of Fletch Lac paint all over it :)
I have several calipers and they all do a good job (cheapies).I would not spend a lot of money if bow building is going to be the main use.
James
IMHO making wood lams is a time consuming PITB and I have better uses for my time.
For your first few bows at least, I suggest buying lams of the thicknesses you need. You can get perfectly good quartersawn parallel or tapered Red Elm lams to put under colored glass (see recent discussions about clear glass quality) for $9-10 each. You don't need calipers to measure stack thickness if you can do simple addition.
I don't make my own lams, but I find that it is useful to verify lam and glass thickness even when I ordered from the good guys. I also find them invaluable for measuring the final bow or measuring a bow I want to copy. Once you have them, you'll find a way to use them.
As for which ones to choose, it doesn't really matter for the precision needed for bow making. The real difference can be how well they hold zero, how smoothly they adjust, lock down, etc. If you get a dial set, I've never had a problem with the $20 ones. The cheaper electronic ones can sometimes start to give erroneous readings when the battery is low, but if you check zero every so often you're usually safe. I doubt you will need it NIST traceable like some of what we do in the labs and machine shops here.
I think it is very important to know each lam thickness. I keep a log book for each bow build. I feel like i need to know exactly what my total stack thickness is..Example..My 58" recurve builds 1# of draw weight for each 0.001" of stack thickness. I got started Like a lot of new guys I ordered a "bow kit" for a 50# bow from a well known supplier..I did not have a way to measure each lamination thickness. My bow came out 58#, I narrowed the limbs slightly and ended up with a 54# bow. So I bought a cheap set of digital caliper and it worked well for a few months, then my bows started finishing out 5-7 pounds heavy. I bought a set of feeler gauges and found out my calipers were off about -0.0015. I bought another set of cheap digital calipers.. I know I don't have the experience or skill set that a lot of others have. I have found that 040 glass can vary from 038 to 042 each piece. I trust my suppliers but there are "factory tolerances" and 038 Glass can be sold as 040.
Just getting back to this now guys....thanks for the reply....lots of good info. I guess its apparent I dont need an ultra precise machinists micrometer to do what I need to do....that makes sense and is good to hear, save me some $$$! Even if I buy materials pre-cut, I still want/need to know what they mic out at for learning purposes....for when I eventually DO cut more of my own stuff (lams). Good to verify that what you are ordering is in fact what you are getting, like Robertfishes mentioned above! Thanks again everyone, as always....this is a great place to learn....with lots of generous, good people to help ya!
Yesterday I ordered a "iGaging Absolute Origin" digital calipers..these are not Mitutoyo's but they are very similar looking and seen to have the same features. I am hoping they are an improvement over the box store brand I have been using. I started having "Zeroing" problems with my current calipers, even with a new battery.. One feature I like is the larger 2032 battery, my other set uses a LR44 battery. I will try to test the new ones at a local machine shop using their standards and compare my feeler gauges to theirs.