Shaper toolholders

[f350ca]

This was from an article on the web (not that everything out there is correct) On metal Shapers by Kay Fisher.

Tool Bit Rake Angles

The rake of a tool bit is the angle (or angles) ground into the top. In the case of a round nosed tool the angle cut back into the tool is called top rake. Unfortunately this same angle is also called front rake and back rake. It’s all the same. In the case of a left hand tool the angle cut sideways into the top of the tool is called side rake.

Tool Bit Rake Drawing by Kay Fisher

"Sorry the drawing didn't Paste from the article"

But no matter what you call it, rake is rake. With no rake the tool will tend to come out of the work and ride on the surface. With too much rake the tool will tend to dig in and pull the holder, and everything it is connected to, towards the work. Although rake is necessary, it is undesirable to grind rake, because this removes metal that would become the cutting edge in future sharpenings.

Armstrong style tool holders hold the tool bits at a 14 to 20 degree angle, eliminating the need to grind top rake. This way, a tool can be re-sharpened indefinitely. Also, the same tool can be used in a conventional tool holder for brass, which cuts best with no top rake.

Rake angles for steel and aluminum should be between 14 to 16 degrees. Rake for cast iron should be 2 degrees and for brass and bronze 0 degrees. My advice is to ignore rake and always use an Armstrong style holder except for brass and cast iron.

On a side note Steve you've never said HOW you managed to bust something as tough as a shaper. Kind of like busting a Sledge Hammer isn't it.

[Rickabilly]

Thanks all,
I see where the idea has started from, It's not something that I've ever experienced and as I think the tendency for an armstrong holder to flex is far less likely than the Hss section simply breaking off especially on shapers where rigidity is not often a problem and where a 5/16" HSS section looks really small I can see why I've not seen the problem occur.

I have once heard that there is another argument that says that due to the angle of the tool bit and the constant interupted cut nose impacts there is a chance that the tool bit might be pushed back up into the holder over time, which I suppose is better than a dig in. Once again I have never seen it happen on a shaper but it does happen on a lathe so it should on a shaper too.

Incidentally when a job is correctly mounted in a shaper dig ins are no where near as catastrophic as the name sounds, often you just need to pick the job up and pop it back into the vise to go again, over my time on shapers I have had a couple of digs and never lost a job as a result,

Best regards
Rick

[stevec]

Greg, it came about as a result of gravitational pull, poor work practice and the confusion of emptying and trying to place the contents of the 53 footer that brought my treasures here.
Just one of the many things I would not repeat were I to live for another 66 years.

[Sunset Machine]

You dropped it? Just hearing that brings a tear to my eye.. Mine almost fell on me, there's a rather large drive assembly up high making it top heavy. It also makes the machine shudder and shake when in operation. Lousy design, I'll eventually use the parts and mount things down low.

Got my toolpost finished and making chips (with a Bull Dog lathe toolholder). Interesting device, the shaper. I've never ran one before. Haven't tried to "shape" anything yet, grabbing a moving machine part with my hand and all that.

Got the thing to "clap" by running the speed up. Got the work to come loose and had to watch the shaper beat it to death until the motor stopped. No clutch, no brake. It throws chips 6 feet, right where I park the car. The concrete is badly spalled, cleanup won't be any fun..

I've more or less settled on a 90 degree pointy tool with a rounded end, no side rake. The tool is touched up by placing a small magnet under the clapper to hold it out at an angle and then bringing the toolpoint down onto some 320 grit emery, which is then pulled out from under the tool a few times and then the magnet is removed. The process leaves a small flat on the end of the tool, apparently critical to obtain a smooth finish.

I can use three-four clicks on the feed and it moves right along at .025" DOC, then reverse the feed and go back to finish with a .005 DOC and one click. One side of the tool roughs, the other finishes, leaving the vice in position ready for another part.

It seems to be working.

[dallen]

heres one I made, thinking about pitching it and starting over got the shank a little crooked

[Rickabilly]

(08-21-2012, 07:58 AM)Sunset Machine Wrote: You dropped it? Just hearing that brings a tear to my eye.. Mine almost fell on me, there's a rather large drive assembly up high making it top heavy. It also makes the machine shudder and shake when in operation. Lousy design, I'll eventually use the parts and mount things down low.

Got my toolpost finished and making chips (with a Bull Dog lathe toolholder). Interesting device, the shaper. I've never ran one before. Haven't tried to "shape" anything yet, grabbing a moving machine part with my hand and all that.

Got the thing to "clap" by running the speed up. Got the work to come loose and had to watch the shaper beat it to death until the motor stopped. No clutch, no brake. It throws chips 6 feet, right where I park the car. The concrete is badly spalled, cleanup won't be any fun..

I've more or less settled on a 90 degree pointy tool with a rounded end, no side rake. The tool is touched up by placing a small magnet under the clapper to hold it out at an angle and then bringing the toolpoint down onto some 320 grit emery, which is then pulled out from under the tool a few times and then the magnet is removed. The process leaves a small flat on the end of the tool, apparently critical to obtain a smooth finish.

I can use three-four clicks on the feed and it moves right along at .025" DOC, then reverse the feed and go back to finish with a .005 DOC and one click. One side of the tool roughs, the other finishes, leaving the vice in position ready for another part.

It seems to be working.

I find it pays just to try all sorts of different tool geometries, personally I amost always run side rake I find it's more important to a good finish on a roughing tool than back rake, keeping in mind that on a shaper the surface you are cutting remains flat cutting with no rake causes chatter on heavy cuts in any thing long chipping, back rake curls the chips up away from the finished surface but they just fall down after they snap off and they can fall randomly to the left or right without side rake, if they fall on the unmachined side eventually the return stroke will pull the tool back over them which can tie them up on the tool where they act like really heavy steel wool scrubbing the machined surface. A little back and side rake means the chips curl up and drop onto the finished surface away from where the tool can pick them up and scour the surface, but don't take my advice, experiment to see what works for you.

And Dallen, I wouldn't worry too much about a little crookedness why not set it up in the mill or shaper and true the base up to the head, It might sound wrong but when ever a welding, forging or bending process is used to manufacture a shanked tool I always start with an over size shank and finish machine it true later, in the case of a shaper the sides of the shank are inconsequential due the the lantern style post even the top surface isn't critical all that matters is that the bottom surface is true, which will usually clean up easily. It looks too good to waste, well done on it so far I do hope you can save it.

Best regards
Rick

[Rickabilly]

(08-21-2012, 07:58 AM)Sunset Machine Wrote: Got the thing to "clap" by running the speed up. Got the work to come loose and had to watch the shaper beat it to death until the motor stopped. No clutch, no brake. It throws chips 6 feet, right where I park the car. The concrete is badly spalled, cleanup won't be any fun..

Oh and Greg,
The best thing I ever did with my shaper was to bend up a simple sheet steel "chip catcher" it just clamps into the tee slots on the end of the table and stops the chips shooting across the floor it's just a simple wall with a hooked top and a trough at the bottom I use a steel trash bin on the floor below the trough and occasionally push the shavings with a wooden stick out of the end of the trough into the bin "simples"

and you might want to think of a DC injection brake if it's taking more than a stroke to wind down. At 60 strokes per minute you can do a lot of damage in 6 seconds/strokes, Personally I've never seen a shaper without at least an emergency clutch (overcentre release on the drive belt) for emergency stops, While Shapers appear docile they can be very dangerous, I once saw a 28" 8Hp shaper break loose and "Barge" itself across the floor when an Apprentice set it on full speed 120 strokes / minute and full stroke, just to see what would happen, He found out all right, another lost it's ram when a similar incident occurred, this time by accident when an experienced tradesman simply selected the wrong gear, Planers are even worse, there were stories where I did my Apprenticeship about a 16' planer table that broke free went through a double brick wall and landed on a roadway, 50 years later you could still see where the wall had been repaired and the big chunck missing out of the steel column it clipped on the way out.

The thing is the rythmic sound and movement lulls you into a false sense of calm and then whoops no fingers, even the tiniest shaper will take your fingers off in a split second, it's not like a Mill or lathe, with rotating tools you're always wary, they scream at you to be careful but a shaper just beats away calmly and you start to trust it.

I love using shapers and slotters and I'm not trying to scare or brag or any of that but I have packed three fingers in ice so far in my time and two of those were where guys thought that the shaper wasn't going to catch them while they flicked a shaving out of the way, "it was going so slowly! I never thought about it I just brushed the shaving away with my brush and then I saw blood"

Best Regards
Rick

[Sunset Machine]

One thing puzzles me: if we use side rake, why is there a reverse feed? For that matter, which direction is preferred? Do we finish with the same tool? My thinking was to use the still-sharp opposite side for finishing, hence no side rake.

[Rickabilly]

The two feed directions are used for moving up to internal corners, you can move up to either internal corner so obviously two directions of feed.

If you apply all of your lathe tool knowledge it will make sense, you usually have two directions of lathe feed as well.

The edge that makes most difference to finish is the "lowest" tip of the tool, once this is damaged it doesn't matter which way you feed the tool, the finish will be rough.

Don't forget A shaper is much more useful than just a tool for making flat surfaces, think dovetails, machine ways, roller troughs and specialised form tools.


Best Regards
Rick

[stevec]

Internal splines, keyways the list goes on.