What is it?

[Captain Jerry]

I'll tell you what it was. It was a very big, very hard, very rusty bolt. The diameter of the remaining head 1.5" so there is a lot of weight there. If you look very closely, you will find that it is NOT! what you thought it was. Its not what I thought it was going to be either.

Prize for the best answer.

Jerry

 

[bearcar1]

A boring head or flycutter.. ??? ???


)left handed nostril inhaler( :big:


BC1
Jim

 

[Captain Jerry]

Sorry Bearcar1, neither boring head nor flycutter. Your third answer was closer.

Jerry

 

[dsquire]

Jerry

Is it some sort of an impeller for a pump? Just guessing.

Cheers

Don

 

[Captain Jerry]

Dsquire,

No impeller, no pump.

Hint #1. It's a mistake.

Jerry

 

[Captain Jerry]

Time's up. No winners.

What is it? Its a reminder that when you are making a tool holder for single point gear cutting, you should keep spindle rotation in mind. In this case, left handed don't cut it. RATS! But then I get to keep the prize for myself.

Jerry

 

[Blogwitch]

But Jerry, if you had carried on the slot all the way across, the other side would be in the correct position.

So all is not lost.

John

 

[dsquire]

Jerry

So in the clue that Jim gave as one of his guesses, "left handed" was the clue. I used "nostril inhaler" as the clue hence the guess as an impeller for a pump. I should have said fancy paper weight or anchor for small boat. :bow:

Cheers
Don

 

[don-tucker]

I protest,thats not fair,cos it looks like its made of copper or PB ,and you dont make tooling out of copper.I want my money back :big:
Don

 

[Captain Jerry]

Due to the huge number of protest (Don), all entries will be returned.

Left handed was the clue. Maybe I should give it to my wife, she has all kinds of special tools to help with her affliction, left handed scissors, left handed potato peelers, etc.

Bogs, there is a reason that I did not carry the slot right across. When the bit makes contact with the workpiece, there is a moment of force that attempts to drive the bit into the slot. Grub screws may hold it but these are small screws. During the cutting of a 60 tooth gear, there may be upwards of 50,000 impacts on the bit. You almost have to expect some movement and any movement lessens the grip of the screw, leading to further problems. I want the cutter to butt against the end of the cut for improved rigidity and transfer of cutting forces.

To fix this one, I will take the slot right across and then drill and set a post in the slot to provide the buttress. There is enough meat in this head to do that. May not be in a smaller tool. It should work out.

Jerry

 

[cfellows]

Can you turn the cutting bit over and spin it the other way? My mill will run either direction...

Chuck

 

[radfordc]

To fix this one, I will take the slot right across and then drill and set a post in the slot to provide the buttress. There is enough meat in this head to do that. May not be in a smaller tool. It should work out.

Jerry

Jerry, after reading your and Rupert's threads on gear cutting and having made a tool like this myself, I immediately recognized the "error". My tool is slotted all the way across and I depend on the 6-32 grub screws to hold the cutter. I've only used it to make some plastic gears so don't know if I will have a problem with the cutter creeping in use or not, but if I do I will remember the post idea.

Charlie

 

[lee9966]

Why not carry the slot across and make a stop? A simple block that fits tightly in the slot so it won't rotate and a bolt into the body of the tool.

 

[Captain Jerry]

Saved!

Extended the slot and added a threaded post for a stop. The post is 1/4" and the slot is 3/16" so the post does not depend on the threads to take the thrust. Instead of grub screws set square to the slot, I decided to try a single wedge screw set at about 30 degrees from the slot. Dramatic increase in holding power.

The smaller holder on the right is the one I used on the donkey gears. The new one is about 5 times the mass. Should be a little more stable.

The bit that I had used before is not long enough to reach the post in this larger diameter head. The single screw seemed to hold so well that I decided to give it a try. I didn't bother to set up the RT, just put a block of aluminum in the vise. made several cuts across a 3/8 face with no movement. Five slots, cut to full tooth depth and all goes great so I changed the aluminum for a bock of steel that I picked up in the scrap yard yesterday. One attempted pass and the cutter retracted like it was swimming in cold water. I think the post would have stopped that but it was really hard steel. Tomorrow I'll grind a new cutter that will be long enough to bear against the stop and give it another test.

Jerry

 

[kf2qd]

Cut a cross slot and put a bar across with a push screw to adjust the cutter.

 

[Captain Jerry]

Cut a cross slot and put a bar across with a push screw to adjust the cutter.

An adjustment screw is a good idea. The post that I put in the slot could be drilled and tapped #4-40.

Thanks, jerry