Ammco Shaper tool question...

Yeah, I enjoy doing things differently, as for showing you folks my set up, I cant. As this is almost all theoretical the setup anyway, meaning, I do not have a 3 jaw set up, nor is it mounted to a plate as I envisioned.
The tool doing what it is doing is really happening.
Due to the length of the tool and the stroke limitations of the machine it is quite an interesting challenge to hold the part in the vise, which inherently leads to issues as I must hold the part in the vise with the jaw of the vise nearly completely open and spacers against the back jaw of the vise to mimic the proposed setup. Now the part is not moving but I think cjtoombs hit the nail on the head so I will try that this evening. I had also thought about turning the tip over and cutting at the top of the bore. I will reserve that for the last ditch effort.
As for my tool, I ground it to a with of .157 on my surface grinder with 1/2 degree side clearance on each side. I machined the groove in the holder to .158 so that thing would fit nice and snug with little slop. I see this first tool as nothing more than a proto tool to verify that I can do what my mind says I can and I will go from there. The info I am getting confirms my thoughts of potential issues. As for locking down the clapper, I see no means for that so something else to keep my mind going.

I will make a video of what I do have setup and post here soon, will also be ordering the chuck today as well.

Regards

Richard
 
I am very interested in your solution and look forward to seeing photos and maybe a video. Keith Fenner of Turn Wright Machine Shop on youtube posted a video of cutting a keyway on a taper. He built a very elaborate jig to hold his work. He eventually had to cut the keyway on the top to reduce bar spring. I posted the vid before, I think it is in the revent series
 
With regards to locking the clapper, some have drilled/tapped holes either side of the clapper box and fix a thick washer to hold the clapper box stationary when required. A simpler 'bodge' (that works on my 7" Acorntools - UK type Atlas) - is to use a long tool (or packing piece/tool-holder) in the tool-slot - and pack it at the top (above the clapper hinge) which also stops the clapper moving...

The former is the better solution - but would involve modding the machine in my case.....

Regards,

IanT
 
So I have gotten far enough ahead on my other projects to allow me to finally play with this machine.
My intent is to cut internal key ways on a taper, yup gotta love a challenge.
So I have all aspects planned out, I will mount an $100 3 jaw chuck to a mounting plate so once I have it set I wont need to move anything. I will I will cut the key way at the bottom of the part so I do not have to make any movement other than up and down on the feed dial to cover the different size tapered holes and all the tapers are the same 5*.

So I made a 3/8 X 1 inch bar and silver soldered a 3/8 diameter rod to that on the business end I cut a notch on an angle and silver soldered a Cobalt bit on that end.
All went well as I was making cuts EXCEPT...ya one of those..

As the tool traveled forward the bit did not engage, even after turning the down feed dial to a point where it should have cut. And then all of a sudden it bit and bit hard and took the whole amount I have moved the dial at one time... My theory is this... the spring used to allow the tool to pick up when the machine is on the return stroke is weak and not holding the tool in the proper position during the power stroke.

My machine came with 2 springs in the position the are conical in shape. I think that putting a stronger spring there will result in proper function. I need to be that small on the tool as one of the parts I am making only has a .468 thru hole and I have to cut a 4mm key in that.

To test this I basically set up some flat stock and set the machine to take a cut with power side feed, it did the same thing, UNTIL I held the tool down during the power stroke. Once that was being done it cut just fine. So my long winded question is: What spec do I use for the spring, or do I just get stronger springs until it cuts properly?

I have attached a photo of the tool..View attachment 243252

Thanks

Richard
When using an extension tool such as you show, the clapper box cannot be used, it must be immobilized; this is usually provided for by setscrews from the sides of the clapper that are dimpled into the clapper itself, and as other respondents have noted, the tool must cut at the top of the part being keyed. In my experience, internal shaping such as this is works poorly, as the tool drags on the return stroke, which tends to dull the tool. The tool needs to be as rigid as possible, that is, as large a diameter as possible, the one shown is too long for it's diameter; as with boring bars, a maximum ratio of 5:1 (length to diameter) should be adhered to, any higher ratio results in excessive springing and chatter. Excessive clearance can also cause problems; in this application, as with all shaper and planer tools, no more than a couple of degrees is advisable as it can cause excessive wear and digging in, so far as back rake is concerned, perhaps no more than about 10 degrees, more can cause digging in. The best tools for slotting on shapers is a tool held in an adaptor that holds it straight out in the hole where the tool post normally is situated, it has a nicely fitted hole in it's center that the slotting tools fit into and are clamped or held by setscrews; it projects straight out and cuts on it's end; I recently showed pictures of them on another thread relating to a milling machine slotting attachment, they may be seen there. I have also seen similar adaptors that have a integral "boring bar" projecting outward with a square hole for using with tool bits; these would work well also as well as the slotting type cutters, but just the same, you need to tie down the clapper and work on the top of the ID of the part.
 
Was he cutting steel or aluminum? I am doing aluminum....so hopefully I can get away with it...

Keith was cutting steel, a very large key if I remember correctly it was 3/4".

My limited experience with the shaper would concur that the clapper needs to be locked while making keyway cuts.

When researching my 16" G & E I came across a patient for a small flat spring that is used to keep the clapper from excessive bouncing when running the machine at a high rate. I see pictures of large Cinci Shapers with a (coil) spring to keep pressure on the clapper, I assume for the same reason. The patient talks about running a shaper at 3-4 strokes per second. NOT ME lol
 
Keith was cutting steel, a very large key if I remember correctly it was 3/4".

My limited experience with the shaper would concur that the clapper needs to be locked while making keyway cuts.

When researching my 16" G & E I came across a patient for a small flat spring that is used to keep the clapper from excessive bouncing when running the machine at a high rate. I see pictures of large Cinci Shapers with a (coil) spring to keep pressure on the clapper, I assume for the same reason. The patient talks about running a shaper at 3-4 strokes per second. NOT ME lol
My 20-24 G&E universal has that spring also, but it is broken, so I use a small coil spring wedged between the clapper box clamping bolt and the upper part of the tool holder. I have never heard of a shaper that ran at 3 or 4 strokes per second! The spring is necessary when running at normal speeds; if you let it hammer away without the spring, the shock tends to make the tool slide work it's way down and cut deeper, even with the lock screwed down tight.
 
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