I took a couple of 2x8x48" red oak boards, laminated them together, and attached the WT device to it. I drilled a couple of 5/16" holes in the base of the spin index to accommodate 5/16" bolts. It's made of cast iron, so it drills pretty easily. After attaching it to the oak base, I clamp the base to my drafting table, and it's plenty solid enough to flo. For the tip weight, I use a drill chuck with a 3/8" hole in the base so I can slip in the Golfsmith laser pointer to do FLO.
I checked the runout on a shaft up close to the collet, and it seems to be pretty accurate. Virtually every shaft I've put in it has several thousandths of runout at the tip, so I've yet to see a really straight shaft. Interestingly enough, shafts that pass the "pool cue" test have some runout in this device. The .609 collet works well for steel shafts. I need to get a bigger one for graphite, but I haven't gotten around to it. It's been a while since I played with it, but it was interesting to observe exactly how the shaft behaved as I rotated precisely. I built this device to use it as an inverted flex board...I cut a piece of UHMW poly and drilled a couple of holes in it to hold the shaft tip, and it sits on my Golfsmith gram scale. The two holes are one inch apart so that by measuring the different deflection pressures on the gram scale, I can get some idea of the rate of increase in pressure as I bend the shaft more. By rotating the spin index, I can get readings at various points around the axial shaft, and I get the expected oval shape with the wide part of the oval at N and the narrow part of the oval at S....or is it the other way around. I've slept too many times since I played with it. It's great for showing customers just how "un-straight" a straight looking shaft is.... I think I put pictures on the Neu-Finder Yahoo group board, but the files section is down right now and I can't check. Best Regards, Royce -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Dave Tutelman Sent: Wednesday, March 19, 2003 8:36 AM To: [EMAIL PROTECTED] Subject: RE: ShopTalk: Straightness finder At 07:43 AM 3/19/03 -0600, Royce Engler wrote: >If you want to get real precise, here's another solution....get a Spin Index >from Wholesale Tools (1709-0010) and a 5C collet to fit the shaft. Chuck >the butt end and rotate the spin index, and you'll see the runout on the >tip. Mount a dial indicator at the tip to actually measure it. The catalog >says $49, but I paid about $30, plus $10 for the collet. You'll need >different collets for steel and graphite shafts.... 0.6 inches isn't nearly >as exact for shaft manufacturers as it is for machinists. Royce, Thanks for the suggestion. A couple of questions: (1) How solid is it? I had the impression from a previous correspondence that you were using an aerospace-surplus indexer that was VERY accurate and solid. Are you actually using this commercial one? In particular: - Is it solid and accurate enough that no wobble is seen with a really straight shaft? (This will depend mostly on the "tightness" of the bearings and the concentricity of all the cylinders and holes.) - Is it rigid enough that it can be used to vibrate a shaft to find FLO? (2) The picture on the web site does not show mounting holes in the base -- or my eyes aren't good enough to see them. How does it mount? (3) Which collets did you need? I assume they were selected from among: 1702-0170: 37/64 = .578 1702-0175: 19/32 = .594 1702-0172: 39/64 = .609 Thanks! DaveT
