Gee Jon, guess what my next project was going to be? I literally printed the drawings out today! I'm thinking I will use the tee section parting blade. Mark is sending me one. In light of what you have found, I think I'll delete the slotted mounting hole. Regards, Preso
Sorry Mark. I recall a while back there were 3 or 4 videos on making a specific Hemmingway tool. Its funny how people make the same thing at the same time. Regarding that slotted hole, the blade angle is not a lot where I placed the normal hole in my second version of that part. The hole on the left is 12.9mm from the top and I drilled the hole on the right 10.9mm from the top (I was trying to find a neutral/average position). You may want to go less on the hole on the right to produce more blade angle. I may actually build another part and drill the hole 9.5mm as per the measurements in the plan.
Hi. If I had not made the one I have now, I would make one of these. Here in the Uk I have the Myford super 7B lathe & with a Bronze bush headstock bearing I was having lots of problems parting off. But I ended up doing a video of making a rear upside down adjustable tool. Which I can fit 3 different sizes of blades to. Works superbly. Thanks for the video. Great work. Steve.
Hi Steve, the rear tool post parting system is a lot better as it has a number of advantages. Mark Presling made one and in his videos he talks about the advantages of rear mounted compared to the conventional front tool post parting tools. Thanks for watching.
Looks to work OK Jon. The main improvement IMHO was to reduce the massive blade overhang. That Eclipse tool was unbelievably bad. So much leverage on the tool post. Interestingly I see you don't appear to use any top relief on your parting off blade. I do and it makes a big improvement to the cutting action. Interesting topic. Cheers Rob
Thanks Rob. Those parting blades that I have are a bit odd. The have a chamfer completely along the top edge. So you have to grind the top surface down to remove the chamfer and make it flat to begin with. I could have ground more off further back to produce more top relief, but I was hoping that the blade angle would help with top relief. It turned out that the blade angle was not as much as my smaller parting tool. I may make another Part B with more angle for the blade which should produce more top relief.
@@thehobbymachinistnz I also don't recommend using an angled cutting edge. I find it pushes the blade sideways away from the job and produces a cone surface (with thin blades). To each their own method. I still haven't tried carbide insert parting off blades ;) HSS works fine for me, so I never bothered. Cheers Rob
Indeed, primitive...
Looking good. I watched Mark's video when it came out. This design seems to work really well.
Thanks Michel.
Perfect outcome Jon, well done. 👍
Thank you.
top job, i enjoyed every minute.
Thank you.
Gee Jon, guess what my next project was going to be? I literally printed the drawings out today! I'm thinking I will use the tee section parting blade. Mark is sending me one. In light of what you have found, I think I'll delete the slotted mounting hole.
Regards, Preso
Sorry Mark. I recall a while back there were 3 or 4 videos on making a specific Hemmingway tool. Its funny how people make the same thing at the same time.
Regarding that slotted hole, the blade angle is not a lot where I placed the normal hole in my second version of that part. The hole on the left is 12.9mm from the top and I drilled the hole on the right 10.9mm from the top (I was trying to find a neutral/average position). You may want to go less on the hole on the right to produce more blade angle. I may actually build another part and drill the hole 9.5mm as per the measurements in the plan.
Very nice work sir. Interesting.
Thank you.
Hi. If I had not made the one I have now, I would make one of these. Here in the Uk I have the Myford super 7B lathe & with a Bronze bush headstock bearing I was having lots of problems parting off. But I ended up doing a video of making a rear upside down adjustable tool. Which I can fit 3 different sizes of blades to. Works superbly. Thanks for the video. Great work.
Steve.
Hi Steve, the rear tool post parting system is a lot better as it has a number of advantages. Mark Presling made one and in his videos he talks about the advantages of rear mounted compared to the conventional front tool post parting tools. Thanks for watching.
Thanks for sharing 👍
No problem.
Looks to work OK Jon. The main improvement IMHO was to reduce the massive blade overhang. That Eclipse tool was unbelievably bad. So much leverage on the tool post. Interestingly I see you don't appear to use any top relief on your parting off blade. I do and it makes a big improvement to the cutting action. Interesting topic. Cheers Rob
Thanks Rob. Those parting blades that I have are a bit odd. The have a chamfer completely along the top edge. So you have to grind the top surface down to remove the chamfer and make it flat to begin with. I could have ground more off further back to produce more top relief, but I was hoping that the blade angle would help with top relief. It turned out that the blade angle was not as much as my smaller parting tool. I may make another Part B with more angle for the blade which should produce more top relief.
@@thehobbymachinistnz I also don't recommend using an angled cutting edge. I find it pushes the blade sideways away from the job and produces a cone surface (with thin blades). To each their own method. I still haven't tried carbide insert parting off blades ;) HSS works fine for me, so I never bothered. Cheers Rob