DIY Fly Cutter for 12mm shank tooling [1619x2048 - 616KB]

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DIY Fly Cutter for 12mm shank tooling [1619x2048 - 616KB] (pic8.co)

Based on the material I had lying around, I made a design for a fly cutter that is constructed from a small section of 2 1/4 (I think) bar, with a 20mm shank welded in. This was done primarily to conserve the amount of larger diameter stock I would use. https://pic8.co/sh/RFqfOG.jpg

With the design sketched out, I cut off a small slug of the larger round. https://pic8.co/sh/bcpb1X.jpg

Then I found some 1" stock, or something around that size, and turned down a ~50mm long shank to as close to 20mm as I could get so it would be a good fit in my biggest ER32 collet. https://pic8.co/sh/Hgp4iq.jpg

With the large puck faced off and a shallow locating recess cut into it, the matching boss on the shank were held together in my bench vise and welded (fairly poorly, I need bigger rods and more power than I can get from my small welder to do a good job on thick steel, but it'll hold). The welds were then turned down to make them a little more presentable (not much). https://pic8.co/sh/Midy7q.jpg https://pic8.co/sh/4ISHFy.jpg

Now it was on to the mill. Using a V-Block I set the face to 10degrees (the exact amount really doesn't matter though) and decked it off until the top was fully faced at that angle. https://pic8.co/sh/6fPfLb.jpg

Then a slot was cut, with one edge being right on the center line. To figure out the center, I used my edge finder roughly on the center of the cylinder, then the DRO's 1/2 function to give me the center line. Offsetting for cutter width, I cut the slot with a 10mm end mill down to full depth, then side milled 1mm off each side to get to final width. A flat was machined on the outer side to make drilling and tapping the fastener holes easier. https://pic8.co/sh/fgGY1u.jpg https://pic8.co/sh/aXttuU.jpg

To drill the holes, I clamped the fly cutter between V-Blocks and aligned the face using a dial indicator. After this photo was taken, I took it out and center punched the hole locations (because I didn't want to stuff around with changin the angle of my mill vise by 10 degrees to make it easy to drill them). The hole locations were aligned by eye (which was plenty close enough), then drilled and tapped M8x1.25 for set screws. https://pic8.co/sh/0iHQGP.jpg <holes tapped>

Job done... now I have a fly cutter https://pic8.co/sh/ju4fbZ.jpg

Now to see if it will leave a decent surface finish....

https://pic8.co/sh/Ab9Dif.jpg

Now that I have a pair of V-Blocks (https://poal.co/s/Machining/682716) I can securely hold round stock in the milling vise. This lets me make my next tool, a fly cutter. This tool will allow me to get much better surface finish straight off the mill than I could get with a normal end mill. Based on the material I had lying around, I made a design for a fly cutter that is constructed from a small section of 2 1/4 (I think) bar, with a 20mm shank welded in. This was done primarily to conserve the amount of larger diameter stock I would use. https://pic8.co/sh/RFqfOG.jpg With the design sketched out, I cut off a small slug of the larger round. https://pic8.co/sh/bcpb1X.jpg Then I found some 1" stock, or something around that size, and turned down a ~50mm long shank to as close to 20mm as I could get so it would be a good fit in my biggest ER32 collet. https://pic8.co/sh/Hgp4iq.jpg With the large puck faced off and a shallow locating recess cut into it, the matching boss on the shank were held together in my bench vise and welded (fairly poorly, I need bigger rods and more power than I can get from my small welder to do a good job on thick steel, but it'll hold). The welds were then turned down to make them a little more presentable (not much). https://pic8.co/sh/Midy7q.jpg https://pic8.co/sh/4ISHFy.jpg Now it was on to the mill. Using a V-Block I set the face to 10degrees (the exact amount really doesn't matter though) and decked it off until the top was fully faced at that angle. https://pic8.co/sh/6fPfLb.jpg Then a slot was cut, with one edge being right on the center line. To figure out the center, I used my edge finder roughly on the center of the cylinder, then the DRO's 1/2 function to give me the center line. Offsetting for cutter width, I cut the slot with a 10mm end mill down to full depth, then side milled 1mm off each side to get to final width. A flat was machined on the outer side to make drilling and tapping the fastener holes easier. https://pic8.co/sh/fgGY1u.jpg https://pic8.co/sh/aXttuU.jpg To drill the holes, I clamped the fly cutter between V-Blocks and aligned the face using a dial indicator. After this photo was taken, I took it out and center punched the hole locations (because I didn't want to stuff around with changin the angle of my mill vise by 10 degrees to make it easy to drill them). The hole locations were aligned by eye (which was plenty close enough), then drilled and tapped M8x1.25 for set screws. https://pic8.co/sh/0iHQGP.jpg <holes tapped> Job done... now I have a fly cutter https://pic8.co/sh/ju4fbZ.jpg Now to see if it will leave a decent surface finish.... https://pic8.co/sh/Ab9Dif.jpg

[–] • 0 pt

Lol, the surface finish on the shank is turd... I think my insert was dull when I was doing that.

A better strategy for me would have been to leave the shank a bit oversize (maybe 2mm extra diameter), then turn it down to final dimension after the welding was done. I managed to weld it in reasonably straight, but there's a bit of runout. Though that doesn't matter for this application since the slot for the fly cutter was machined relative to the shank, not referencing anywhere on the head.

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