Here's some pictures of the set up I used.
This is the saw arbor in a shop made collet chuck. The saw is 2-3/4" OD with a 3/4" hole. It was the only one I could find in the width I needed, 0.114"
Another shot. If I do it again I'll place the saw all the way back on the arbor instead of near the end. Might be a bit more rigid that way. The way I ended up cutting was from the bottom up. I was nervous about coming from the top down since that would've been a climb cut. I cranked the milling attachment as far down toward the bed as it would go then centered up the piece on the blade. I then fed in the cross slide. Contact was made with the work piece around 0.650" in. I then fed in slowly to my final number of 0.875" and from there began feeding upward to complete the cut.
Here's the part I cut. Finish in the slot is pretty good. The part was held in a collet block which was fixed into the milling attachment on the lathe. I needed the slot to be 0.875" deep from the point of the cone but based on the dimensions of the saw blade and arbor I could only go 0.8125" deep. I then realized that since the part comes to a point the 0.114" wide slot will be taking about 0.067" off the width. Thus the workpiece just cleared the arbor by about 0.005"!
Here you can see that the slot is not exactly on center. Honestly I just eye-balled it. I wasn't sure how to indicate it... D'oh!
I broke down the setup last evening. For these pics I just mocked it up again, except for the milling attachment part. What's weird though is that out of curiosity I checked the runout of the arbor on the solid part of the shank, it was around 0.003"!
Then I checked the runout of the collet chuck, it was also around 0.003". I then took the chuck off and checked the spindle, it was about 0.0005".
I also have an ER40 collet chuck that goes into the MT3 spindle bore with a draw bar. This one I purchased... from Shars I think. When it's installed and tightened up it has only about 0.0005" runout on the outer body of the chuck. I don't use it much though because long workpieces cannot pass through, I usually just use it to hold endmills for milling operations. Next time I'll probably use it to do the slotting.
So finally, I reinstalled my home made collet chuck and checked the runout again and now it's reading between 0.0005 and 0.001"!
I turned this whole chuck on the spindle so I was expecting it to be pretty good on run out. Any ideas why it can change when removed and reinstalled?
