Sometimes it's cheaper to just buy it rather than build it...

This is what happens when you look at something and say, "I can make one of those WAY cheaper than that!" I've been into archery for a number of years, although less so recently. Getting back into archery and making my own archery equipment, I decided I wanted to make custom arrows both for my and my wife's bows, as well as producing custom sets for sale somewhere like Etsy. Cresting arrows is one of those things that makes a set of custom arrows look classy and a BIG step above simply applying a little stain and finish to otherwise simple arrows.

From http://www.stickbow.com/features/arrowmaking/crest1.cfm

Okay, so that photo on the top, of the motor attached to the dimmer switch and melamine shelf? This is something like Plan C at this point. The white wheel stuck on the motor was purchased from McMaster-Carr for $25 (price plus shipping). I realized the other day when fiddling with this and trying to figure out how I was going to support the arrow shafts, that the original design of the stationary motor with an arrow nock chuck doesn't take into account the differing sizes of arrow shafts. The three most common sizes of arrow shafting (at least wood arrows - my specialty), are 5/16" 11/32" and 23/64". Not a whole lot of difference, but enough that if the motor doesn't move, then in order to accommodate differing sizes of shafts, either the arrow supports need to be able to be raised up and down, or they need to be fixed and the motor must move.

This was the original configuration which seemed like it would work, until I made that realization about differing arrow shaft diameters. This is also the design of pretty much 100 percent of all the DIY cresting lathes I could find in my internet searching. There were variations on the design but all seemed to be a fixed motor and fixed supports for the arrow shafts, which work fine if you only ever make one size of arrows using on shaft diameter. If you're only making arrows for yourself and you typically shoot the same poundage weight on all your bows, then you'll probably never have a reason to make arrows in different shaft diameters.

 

This is the Plan B (Plan A involved another motor that wasn't powerful enough to effectively spin the arrow shafts), setup showing a 5/16" arrow chucked into the motor. This in fact doesn't even work for me, because I just bought four dozen sets of Port Orford Cedar arrow shafts in two different spine weights in 11/32" diameter. Already I was running into problems of how to accommodate differing shaft diameters and this is even before I start taking custom orders in the future. What happens when my lathe is set up for 5/16" as I was all set to do initially, then realize that the arrows won't sit in their cradle on the bearings when I'm trying to crest 11/32" or 23/64" shafts? Well, onto Plan C I guess.

I decided the best route was to raise the motor on a swinging arm and have the rubber-tired wheel sit on the arrow shaft and spin it while the arrow shaft sits in a cradle composed of several sets of bearing-like wheels. In my case I was going to use nylon wheels like those used for shower doors and such. I suspect these would not have worked well because they'll generate too much friction since they're not true bearings. True bearings as I looked into purchasing from McMaster, along with suitable lengths of rod to slide them onto, would've pushed the cost of materials for this cresting jig to over $150 or so. The lowest level of what I would consider a decent cresting lathe is one that costs $180. There are a couple of cheaper options but they're basically junk.

I tried an experiment and ran the motor while pressing an arrow shaft up against it, only to find that while the motor has high rpms, it has almost no torque. In a sewing machine where it normally belongs, it's hooked to a larger pulley in the machine with a belt and via some sort of gearing reduction is able to effectively do what sewing machines do. In this capacity, all I can see it doing is bogging down and not spinning the arrow shaft effectively enough.

On top of that, the wheel is out of round and would likely induce oscillations into the arrow shaft which would hamper getting good cresting lines. You see lots of posts about guys who've built their own cresters but little in the way of photos of the sort of results they get. A guy I know bought a cheapie crester from the guy who runs one of the archery shops. He got it cheap because it wouldn't spin the arrow straight, instead inducing hops as the thing spun. He said for his purposes it worked okay, but frankly his cresting was kinda sloppy and looked like what you'd get from a tool that didn't work like it was supposed to.

So, at this point I could continue on and spend a couple more hours or more trying to see if this would work, but I think in the end I'm going to be disappointed and end up with hours more of my time and effort wasted. So, I suppose eventually I may have some use for the motor, and possibly for an out-of-true drive wheel. If I'm going to get into cresting my own arrows and trying to do custom orders for other folks then I'm simply going to have to pony up the cash and buy the professional model. There's a certain point where it becomes a case of diminishing returns when you're trying to do something on the cheap. Yeah, I could probably make a crester for less than $180 but probably not buy much, and the results it produces will probably look like they were made by something cobbled together out of bits of junk.