Thread: A question for the Shapeanisters out there

Odd....i normally get a line like that on the other end of the piece. Unless your return is so fast that the tool is bouncing of the trailing edge and landing in that spot.
Can you try lifting tool manually at the end of the cut and putting it down at the start? 16m/m is pretty slow, even by the Queens standards....I try to run at 100fpm, but invariably i end up in 3rd gear mostly.

Could be a flaw in the material you're machining?

Jordan

Hi Michael,
Did you try to see what happened if you change the speed?
Are the marks where the crossfeed starts?

That tool looks like its 90degs out for what I understand a shear tool.

Stuart

HI,

I get the same even using aluminium, I thought it may have been due to not having enough clearance at the end of the stroke (before the tool head starts its return run).

Ben.

Originally Posted by bwal74

HI,

I get the same even using aluminium, I thought it may have been due to not having enough clearance at the end of the stroke (before the tool head starts its return run).

Ben.

Agree with Ben.
Lengthen your return stroke by the a distance the chatter marks are off the edge of your block.
Goodluck.

Stroke length - I have 1/4" over at the front and 1/2" at the back. I would have thought that was ample - it's usually the recommended stroke in most shaper texts.
Speed - yes, it is slow - it should probably be about twice that, but then I lose that mesmerising action (and as well as that I don't want the shaper getting too excited - it sits on feet and is not bolted down).
Shear tool - I thought that was what it was called but I could be wrong. It produces a nice finish anyway. The tool is feeding from photo right to photo left.
Cross feed is on the return stroke.
Material flaw - possible but unlikely. This piece is cut from a bar and I've machined other pieces from the same bar without issue.

I'll try changing stroke length and see what happens but I'm not sure that it is that simple.

Michael

Micheal I feel that the radius at the leading edge of the cut may be telling you that you have
a bit of a tool bounce happening there, tool geometry, probably wants a smaller radius and a
bit more back rake ? But then what would I know, my shaper is gathering dust still

john

Originally Posted by Michael G

Shear tool - I thought that was what it was called but I could be wrong. It produces a nice finish anyway.

Well if its working then there is no problem then . Just the ones I have seen have more "rake"?
Did you see this video from RC?
https://www.woodworkforums.com/f65/sh...ishing-145554/

Originally Posted by Michael G

Cross feed is on the return stroke.

Yeah but its normally late in the stroke. If you feed by hand you can hold off until the tool is clear of the work... if you still get the mark then thats not the problem.

Staurt

Hi Michael,
Have you tried putting a chamfer on the leading edge, the edge the tool hits first when cutting. It used to be standard practice. Also make sure the clapper is seating properly. Sometimes oil between the clapper and its seat can cause that mark.

Phil

Had a bit more of a play today (sorry - I mean a serious scientific investigation). All cuts were approx 20 thou.
Firstly the tool. As I said it seems to give a reasonable finish. The back relief is around 60 degrees.
P1010560 (Medium).JPGP1010561 (Medium).JPG
I checked the clapper both for play (none felt) and for oil behind it - a little so it was cleaned. It didn't make the clapper feel very much different.
I tried a longer stroke and the marks disappeared but a 6" stroke to machine a 3" part seems very wasteful. I changed it back and then the marks were not present.
Changing speed - this one is odd. When I went slower, I got this -
P1010562 (Medium).JPG
The marks had moved from around 1/2' from the leading edge to around 2" and were not as uniformly placed. I then went to top speed. A little scarey, but I survived. Te results were as below
P1010563 (Medium).JPG
As you can see I've gone from a roundish mark to a dash. That would be the back of the cutting edge of the tool as the relief is too great for the rear of the tool to contact. While the marks look in a line, the cross feed is around 5 thou/ stroke so in reality it is bounce from separate strokes.

Michael
(still mystified)

If all else fails, it might be time to try a gooseneck tool holder.
For me, it transformed a chatter prone job to a smooth one straight away.

Jordan

Michael
Is the Gib adjustment at the front, near the table good. I had at one time a similar patten and it was traced to wear in the ram surface over about the first 1/4 or a bit less of its length. By adjusting the Gib's as best as one could to compensate it was passable. Does a straight edge on the work piece indicate any drop off where the tool first contacts the material. Alan.

Hi Michael,
Thats not a sheer tool as I understand it. Turn it 90 degrees anti-clockwise and it will be closer to what I think of as a sheer tool.(but thats besides the point)

That edge looks blunt.(but pictures can be tricky things)

I'd make sure the tool is sharp and be tempted to try limiting how far the clapper can swing up(though you might just move the marks lol).

Stuart

Stuart, the tool feels sharp, so I think (for the moment anyway) that's not an issue

C-47 (Alan?), there is a radiusing of the leading edge on the piece - you may just be able to see it on the photos in the first post. This machine was ex TAFE. Apart from a prang or two I was told that it hadn't done much work. Looks like strip down is on the list (there's always something...)

Thanks,
Michael