MetalworkingFun Forum

Hi,
Just wondering does anyone have one? If so do you use it much?

DaveH

Huh, ..............

DaveH

Dave,

I have one. I use it to pick my nose. Actually, I have 8 of them. My thumbs don't fit.

Ed

I knew it was just to sophisticated for you lot in the Northern Hemisphere.


DaveH

I do not have one, but I have used them. The two companies here who sell products I've used are Slater Tool and Genieve Swiss. There are a few more, but those two seem to have the major market share in the US.

I'd be interested in making one, but not motivated to the point that I'd try drawing a rotary broach body. I could probably make the broach tools themselves without drawings, but you can buy them cheaper than you could buy high end tool steel, turn the blanks, heat treat, and finish grind them.

Ken ....... my hero to the rescue
I'm thinking along the same lines, need a drawing or two. I'm not sure about the 'wobbly bit'. The broaching tools I can make, it is just the holder I'm not too sure about.
I was thinking if someone had one they perhaps wouldn't mind taking a few dimensions.

This is one by Mike Cox http://mikesworkshop.weebly.com/rotary-broaching.html


DaveH

One thing I do remember is the tool is 'off axis' by 1 degree.
The reason I remember that is there use to be a TV ad for Phensic (I think) headache tablet, the ad went something like " Feeling one degree under - take a Phensic"
I amaze myself sometimes

No idea how the achieve the 1 degree off axis.

Anyway I'll go on talking to myself you just read

The title was a little misleading so I've amended it.

DaveH

I have found a drawing - Some of you may know him "Ken I" he's a member of HMEM.
And he's from Cape Town - just down the road .

DaveH

Hi Dave,
I dont think it *has* to be 1 degree, as long as the broach has enough clearance to prevent the cutting edge rubbing, iirc 7 - 10 degrees, and as long as there's some cutting edge rake (what I remember seeing is "dishing" the front face with a.small dremelloid grinding wheel, poss after hardening?)

Most homebrew ones seem to fit in the tailstock ram and have the bearing seats set at an angle to the Morse taper and offset slightly to get the cutting edges on centre, ok but means the bits need to be accurately made to the same lengths, if I get the necessary tuits I'll make.mine to go on the qctp, that'll allow easy adjustments to get the cutting face on centre and adjust the off-axis angle if required for different materials?

Hi Dave,
You are correct the 1 degree is not the broaching tool (bit) clearance, it's the holder, that holds the tool bit off axis by 1 degree. (I think ) causes the 'wobble'.

All the ones I have used fitted in the tail stock or the capstan.
Some needed a bit of hefty force as well, the maximum size I'm thinking will be 6mm (1/4") square or hex.

DaveH