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30th Jul 2017, 07:25 PM #1Golden Member
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Shaper - how to stop the dreaded 'clapper slap' (.. 'bounce')
'clapper slap'. Go on. Say it five times quickly after a few drinks.
I have recently got the Alba 1A 10" shaper totally operational again. Lovely thing (late 40's- mid 50's perhaps):
IMAG1593.jpg
Yes, the red is all original paint. Cool eh.
I'm making a toolholder for a slotting tool (for gears and motor pulley on the 'basket case grinder'). This is my first go at making something on the shaper and despite some fiddling and experimentation, I get this:
IMAG1592.jpg
Slapper clap .. erm, I mean Crapper slap. Er .. I mean clapper bounce.
Tool is held like this and I am cutting to the left (in the photo):
IMAG1596.jpg
Despite the material being the gummiest, most awful scrap-heap stuff you can imagine - and then some, if I hold up the tool on the return stroke it ain't too bad - bit that ain't cricket:
IMAG1595.jpg
Any hint or suggestions .. apart from avoiding spoonerisms is public places?
All help and comments appreciated.,
Greg.
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30th Jul 2017, 08:44 PM #2Most Valued Member
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- Apr 2012
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G/day Stray, can you show some detailed pics of the cutting tool and clapper please?
cheers, shed
ps that shaper is a cutie
pps. its not running backwards is it?
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30th Jul 2017, 09:54 PM #3
Hi Greg,
Nice machine !
The further out the tool sticks the more it will bounce the clapper box. Now I have seen machines with a layer of news paper under the clapper, I wonder if that has been done to reduce the noise or the bounce.Best Regards:
Baron J.
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30th Jul 2017, 10:53 PM #4Golden Member
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Shed, thanks. Will get pics here tomorrow. It isnt running backwards. ) The return stroke is the fast stroke.
Baron, thanks re stickout - good tip. Ill give it a go. I have some more of this gummy material i can use to experiment with. Ill be hapy to see it gone!
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31st Jul 2017, 09:13 AM #5Golden Member
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I am under the impression that the clapper lift on the return stroke is to stop the abrasive wear on the tool cutting point. I suspect that the speed of cut may be high; causing a high lift of the clapper at the start of the return stroke and the tool point hits the work as the clapper returns to position it lifts off again (bounces) and on the second return causes the second impact mark.
The noise of the clapper box returning is just part of the running of the shaper. It would seem that the Alba 1A 10" has a very free swinging clapper box. They can also have clacks from the bottom of the centre rod(tuning fork) round pivot and the sliding bush due to wear. This unit has a bad habit of seizing up on the top pivot that joins to the ram due to lack of lubrication.
Ken
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31st Jul 2017, 10:09 AM #6Philomath in training
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Just thinking about it a bit, I'm wondering whether the bounce is also due to how far away the ram reverses once it clears the work. If it hits the work on the return stroke when it's speed is low then it should be fine but if it is traveling at speed, hitting the edge would encourage it to bounce?
Michael
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31st Jul 2017, 01:35 PM #7.
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Hi Greg,
A number of manufacturers incorporated tool lifters in the design of their shapers. Some were lever operated, others cable. Here is a image that provides a glimpse of a lifter fitted to a rather robust Garavaglia ( courtesy of Tony's Lathes.co site). I don't imagine that it would be too difficult to come up with a version to suit your shaper.
Bob.
img0.jpg
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31st Jul 2017, 03:42 PM #8Most Valued Member
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Hi Michael,
Are you suggesting that a too generous tool travel past the workpiece on return stroke is not good practise because it hits the tool edge at the maximum set speed, as opposed to only clearing the workpiece by a minimum amount so that it reaches maximum stroke speed when it's already cutting?
I never really thought about it but it sounds logical.
Edit: there is no way that the tool is making those marks on the return stroke. The tool is literally just loosely sliding across, there is no force applied, unless the angle of the claper is incorrect and does not allow the tool to properly lift off but that does not seem to be the case from the picture.
SimonGirl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.
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31st Jul 2017, 04:00 PM #9Intermediate Member
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- Mar 2017
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- gold coast
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I have an xps file describing exactly how to fix your problem I'll pm you
owen
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31st Jul 2017, 06:30 PM #10Philomath in training
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Basically yes - that's my theory.
If the tool is traveling at a fair clip it will hit the edge of the work and bounce up, coming down further along the work.
Michael
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31st Jul 2017, 10:43 PM #11Golden Member
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Thanks all - I'm guessing we're all a bunch of hairy shaper weirdos ) maybe I am yet only a 'proto' hairy-shaper-weirdo! )
Owen PM sent. Interested to see what you have.
Ken, yes - it does swing quite freely - I have had it apart and it is all as sweet as a nut - no binding or wear - so I am guessing that is how it us supposed to be.
Bob, nice. ) Thanks.
Michael, Interesting. You may have something there. Though I have it set to clear the end of the workpiece by only about 1/2" - so not too excessive - but it sounds fair enough. So worth an experiment or two. I have more of this gummy crap to get rid of. ) I think I have the shaper at its lowest speed, but I'll check.
Shed. Pics (something you're looking for?):
IMAG1597.jpgIMAG1598.jpgIMAG1602.jpg
IMAG1599.jpgIMAG1600.jpgIMAG1601.jpg
Greg.
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31st Jul 2017, 11:14 PM #12Most Valued Member
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G/day Greg, my way of thinking is that when the tool falls on the back stroke it shouldn't make a dent as on the cutting stoke immediately prior the metal that is now dented should have been removed, there should not be enough flex/elasticity in the clapper to cause this.
Cutting to the chase I think that the radius on the tool is too large and it needs a better edge, I think the tool is under too much load and pushing everything away from the job then springing back on the back stroke under no load causing the tool to ker doc the job.
That shaper looks to be in excellent condition and I can you tell you straight that I am green with envy , but I reckon also that maybe it wouldn't hurt to move your ram out to the end of the cut and put an indicator under it, give it a bit of a lift and see how much play it has.
cheers, shed
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31st Jul 2017, 11:38 PM #13Most Valued Member
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Greg I tried to check out your work piece and I can't see it to well but I think that I can see a line along the start of the cut end, maybe?
It looks like the tool is contacting the job and then lifting, If you check with a straight edge you may find the edge at the start of the cut is slightly tapered down, maybe?
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1st Aug 2017, 06:33 AM #14
Hello Greg,
Looking at your pictures of the toolbit, it seems/appears that the leading edge is slightly burred, and I think that a little more top rake might help as well. Imagine the tool as though it were a lathe tool, the angles, feeds and speeds would be similar, I think.Best Regards:
Baron J.
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1st Aug 2017, 09:21 AM #15Golden Member
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Shed/Baron, thank you.
Shed - I suspect the same. And I believe what you see at the start-of-cut end is indeed that. Some spring there. I'll do the lift test to see if there is play - it is possible that the gibs might not be snug enough. There is some wear there.
The workpiece has some small overhang past the ends of the vice - which might cause some spring. And add to that, the vice is not exactly a precision tool - it is shop made from castings and rests on a shop made swivel plate. Ive been calling it 'viceosaurus'.
I'll likely not get time in the next couple of days but I'll do some tests as soon as I can.
Baron, I'll revisit the tool geometry thanks. I actually cleaned it up a bit before the pics. I'll switch to some HSS - I've no idea how old this one might be so it may not even be HSS.
re the condition of the machine. yes, it is in pretty good nick. A bit worn here and there yes, but not too bad. I did a nut-and-bolt on it and replaced bearings/bushings and got rid of years of muck. I'd post a link to a re-build pic thread but photobucket no longer shows the images in the thread. I've got to pay $399 US / per year for that privilege now. Darn eh.
Thanks again.
Greg.
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