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Shaper tool slot problem.
John Hill:
Just a thought, if you are cutting a slot the width of the tool what happens on the reverse stroke? If the tool tip is being dragged backwards in the slot the corners will be getting rubbed which might be enough to foul it up.
P.S. My shaper is called 'Sally', she is the only machine in the shop with a name and its a female name, because, well..... its female! ::)
ieezitin:
John.
I gave some thought to the width too. I come up with maybe I did not have the tool dead vertical and the cutting edge being perpendicular was slightly tapered or angled wrong, (saying that it was ground by hand and eye and my sight aint what it used to be).
Your other note on the tool sliding back and rubbing was a concern too. There is no room or clearance for the tool to go back to position without some interference. Another thought I had was that the tool size (being 5/16 square) is a little flimsy or in other words not robust enough, I think I may be getting too much spring. I am going to profile a ½ piece of HSS and see if this helps the forces are excessive to say the least. Another thing I am going to try is to grind up a v-tool to rough out the material then slide the correct profiled tool down it to finish it up.
I envy you with the mechanical toolpost feed. Was it hard to design and build?
I know of Sally, she is a little cutie I have seen her in some of your posts. She was made by Adept (or labeled as Adept) I believe she was made by the Atlas company here in the States. I could be wrong, I know this well my wife tells me a lot so it’s got to be true.
Happy days…. Anthony.
John Hill:
--- Quote from: ieezitin on March 16, 2011, 10:49:17 AM ---John.
I gave some thought to the width too. I come up with maybe I did not have the tool dead vertical and the cutting edge being perpendicular was slightly tapered or angled wrong, (saying that it was ground by hand and eye and my sight aint what it used to be).
Your other note on the tool sliding back and rubbing was a concern too. There is no room or clearance for the tool to go back to position without some interference. Another thought I had was that the tool size (being 5/16 square) is a little flimsy or in other words not robust enough, I think I may be getting too much spring. I am going to profile a ½ piece of HSS and see if this helps the forces are excessive to say the least. Another thing I am going to try is to grind up a v-tool to rough out the material then slide the correct profiled tool down it to finish it up.
I envy you with the mechanical toolpost feed. Was it hard to design and build?
I know of Sally, she is a little cutie I have seen her in some of your posts. She was made by Adept (or labeled as Adept) I believe she was made by the Atlas company here in the States. I could be wrong, I know this well my wife tells me a lot so it’s got to be true.
Happy days…. Anthony.
--- End quote ---
Anthony, Sally is an English girl made by what I understand was a quite small but nonetheless long surviving family firm while also built very small, almost rudimentary, lathes for hobby and home machinists.
The down feed was not difficult to make as I found a small ratchet wheel which fitted neatly under the downfeed handle and it was only a matter of making a quite simple pawl which is driven by a flexible (bicycle brake) cable from an handy part of the feed mechanism.
There is a technique used when cutting T-slots to flip the tool up right clear of the work on the return stroke. I have never used it and cant recall the exact procedure but I think it requires a simple hinged flap on the back of the tool, the hinge is arranged so that when the tool reaches the end of the stroke the flap of the hinge falls down causing the tool to be raised on the return stroke.. That might be worth seeking out and would perhaps solve your possible problems with the tool rubbing.
Bryan:
Anthony, one of the first things I tried with my shaper was slotting to make tool holders. I too found it problematic. Tried a few things, with limited success. In the end I decided it needs a spring holder, but I'm only guessing. Plenty of threads about them, eg: http://www.practicalmachinist.com/vb/antique-machinery-history/more-spring-tools-208588/.
John Hill:
My gut feeling is that it is a question of absolutely precise rate of down feed. Too much feed and everything flexs then breaks free so you get a horrible finish and the next stroke is even worse! Too little feed and the tool rubs and blunts and the piece may work harden.
Tool lifting on the return can only be a plus and the hinge flap on the tool is easy to arrange, I assume having never done it myself.
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