Author Topic: Shaper tool slot problem.  (Read 11588 times)

Offline ieezitin

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Shaper tool slot problem.
« on: March 15, 2011, 02:59:18 PM »
Any of you guys got thoughts on my little project here. I own an Atlas 7B shaper and I am trying to slot a piece of steel 1/8 wide x 1” long x 5/8 deep.

I ground up a small piece of HSS square stock and profiled it as per sketch. I had the machine on the slowest speed and stroke. The tool hit rather hard and tore the material (not cut) and it sounded like a file snapping every time it went in for material removal. My results were poor. Any suggestions on tool geometry, work holding and or just machine set ups.

BTW I feed the down feed with the toolpost slide and the work was held in a shaper vice with a minimum of material showing for the machining process.

Thanks for all future help.    Anthony.
If you cant fix it, get another hobby.

Offline John Hill

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Re: Shaper tool slot problem.
« Reply #1 on: March 15, 2011, 03:17:00 PM »
I suggest touch up the cutting point on the tool and try again but this time get the machine running with the tool clear of the work then very, very slowly lower the tool until it makes contact with the workpiece.  The first touch may give you a clue, if the tool skids over the surface or digs right in, if it hits the edge of the work then flicks forward, they are all clues and maybe whats needed for someone to help.

John

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Offline DavidA

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Re: Shaper tool slot problem.
« Reply #2 on: March 15, 2011, 04:33:36 PM »
ieezitin,

Have you tried running a file across the surface ? maybe it's case hardened.

Dave.

Offline ieezitin

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Re: Shaper tool slot problem.
« Reply #3 on: March 15, 2011, 07:24:33 PM »
John.
All in all that was my approach the first time. And right from the start it was complaining. I got down into the steel about 1/16 where I had two sides and a flat I then lifted the clapper box and with a honing stone touched up all facets of the cutting edges. Is still got the bad surface finish and no nice curls that I expected.

Dave its not hardened its hot rolled regular steel stock (run of the mill steel stock in other words). Saying that the mill scale could be tough but like I mentioned above once I was in the body of it I re-sharpened the tool bit.

I was wondering if the tool geometry was correct its been twenty years since I last used a shaper and I have forgotten a lot about them and the tooling shapes but I seem to remember the tooling is not quiet far off from being the same as the lathe requirements. Where I came up from this shape was the hand broach sets you get the tooling is shaped like that. Anywho ill give it another go later see what turns up.

Happy days………..     Anthony.
If you cant fix it, get another hobby.

Offline John Hill

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Re: Shaper tool slot problem.
« Reply #4 on: March 15, 2011, 07:58:04 PM »
Yea, sometimes my little shaper refuses to continue when using a wide tool.  When that happens I swap to a sharp pointed 'V' tool tip and once it has a few 'scratches' in the work I change back to the wide tool and carry on.

I suppose once the tool skips, jumps, or whatever a couple of times it has put transverse ridges on the cut which cause the tool to skip and jump some more,  I think of it like the effect of corrugations on a dirt road.

BTW, with my little shaper I had no success whatsoever with cutting slots, I only had to over feed by a tiny amount and it would all go to custard and reducing feed would not recover the situation.  So I fashioned a fitted an automatic down feed and alls well.
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Offline John Hill

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Re: Shaper tool slot problem.
« Reply #5 on: March 15, 2011, 08:02:39 PM »
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! ::)
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Offline ieezitin

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Re: Shaper tool slot problem.
« Reply #6 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 ˝ 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.
If you cant fix it, get another hobby.

Offline John Hill

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Re: Shaper tool slot problem.
« Reply #7 on: March 17, 2011, 10:56:47 PM »
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 ˝ 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.


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.
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Offline Bryan

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Re: Shaper tool slot problem.
« Reply #8 on: March 18, 2011, 06:52:11 PM »
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/.


Offline John Hill

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Re: Shaper tool slot problem.
« Reply #9 on: March 18, 2011, 07:58:16 PM »
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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Offline ieezitin

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Re: Shaper tool slot problem.
« Reply #10 on: March 19, 2011, 11:39:21 AM »
John.

I agree with the feed rate. I was playing around yesterday with the toolpost slide action and the table lift action and I got two results. For the life of me I don’t understand why the manufactures did not install as standard mechanical tool feed systems as stock on the machines. I know most including my own makers offered the system as an extra just to squeeze extra mular out of ya but really that’s like selling a lathe without a lead screw.

Anywho I am making progress in getting familiar with the tooling and finishes I am getting, that hot rolled  piece was truly a piece of trash even my small mill had a fit trying to mill it.
I was planening some AR500 steel(abrasive resistant Rockwell 500 steel) yesterday and my results were very satisfying indeed the roughing tool I used chattered a bit but the knife point finishing tool done a super job. In fact I was taking .040 cuts with the knife tool and decided to stay with that, I was cutting a slot 4” long x .640 deep x 980 wide which took about 1-1/2 hours, slow I know but fast for me considering I don’t have a full size mill.

Bryan.

I read that full article you linked me. Even though I knew of spring holders I never considered them for my particular problem on the small width slot I need. Through reading of their experiences and findings it makes perfect sense to me of the results they are getting. In the PDF supplied shows a very simple homemade tool holder one of which I am going to make and try for my 1/8 slot needed. The beauty of it is that it gives the same results on the lathe. I liked the one gentleman’s comments that he uses nothing but spring type tooling even on his CNC lathe. This type of tooling was pretty big way back yonder but forgotten today Ummmmm.   Anyway I thank you for your suggestion even though my afternoon now is making such a holder.

Happy days…………..   Anthony.
If you cant fix it, get another hobby.

Offline John Hill

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Re: Shaper tool slot problem.
« Reply #11 on: March 19, 2011, 05:22:54 PM »
I am pleased you are getting more positive results with a change of materials. :thumbup:


I suppose there is a place for the spring tools but I do noT understand how they could be an advantage when 'spring' is what seems to cause most problems for shaperites!
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Offline Bryan

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Re: Shaper tool slot problem.
« Reply #12 on: March 19, 2011, 06:01:02 PM »
John, I believe the spring holders work by changing the location of the flex. The fact that they also add more flex is a red herring. If you made a rigid holder that set the cutting edge behind the clapper I think you would get the same result, or possibly better. When I get a chance I will attempt to prove (or disprove) this.


Offline Bryan

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Re: Shaper tool slot problem.
« Reply #13 on: May 30, 2011, 02:16:30 AM »
Anthony, John and other shaper-nuts. I made an offset holder but it didn't help much. What did help was reducing front clearance to about 3 deg. And fine feed, eg .02 - .05mm.


Offline Davo J

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Offline ieezitin

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Re: Shaper tool slot problem.
« Reply #15 on: May 30, 2011, 08:26:24 AM »
Dave.

I appreciate your sharing with the tool bit grinding info, I found the link you suggested very informative and useful. Its been awhile since I have seen the inside of the shop due to a large work load but I plan soon to slide back in and straighten out my shaper woes.

I will post my findings on my little 1/8 wide slot.

Thanks again,      Anthony.
If you cant fix it, get another hobby.

Offline ieezitin

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Re: Shaper tool slot problem.
« Reply #16 on: May 30, 2011, 08:34:15 AM »
Bryan.

I take it you made a spring type holder?, try what Dave suggested and let us know on the results.

A piccy of the holder would be appreciated.



Anthony…..
If you cant fix it, get another hobby.