making rotary broaches

[kd0afk]

First off, I'd like to know why a 10 cent piece of drill rod comes to be $50 when it's made into a rotary broach.
Second, I would like to be able to make my own bits and save $49.90. I could see charging that much for an endmill but these things are pretty simple looking. For a hex broach, after set up, it's basically six passes at the same setting and a notch on the shank maybe it hit with a ball end mill on the end.
*end of rant*
Anyway, I don't have a mill so I am having to cobble something to do these. Does anyone make a dovetail cutter that only cuts a 2 degree dovetail?
If no dovetail what would be a safe way to hold a collet block at a 2 degree angle on the lathe?
They sell bits with a 2degree taper but that won't work.

 

[Tin Falcon]

First off, I'd like to know why a 10 cent piece of drill rod comes to be $50 when it's made into a rotary broach.
Second, I would like to be able to make my own bits and save $49.90.

You are correct doable . easy on a mill. there are tapered mill cutters for mold makers but the tapers are in the opposite direction of a dovetail .


you could use a lathe as a mill if needed.

Just use a hex collet block in a vise set a stop and lift the back end to create a 2 degree taper. just do the math like setting a sine bar.
Tin

 

[kd0afk]

I'm looking at getting a cnc spindle and mounting it so I can mill on the lathe. I think that is what's called for here. I'll get it going once all the pieces are in place.

 

[polygon]

We manufacture rotary broach tools and I know what you mean about cost. However, the cost of business these days requires these prices to cover all the expenses. You mentioned the material, manufacturing, equipment, etc. and there's also the quality systems to insure consistency, packaging etc. - that added value adds some cost. Also, to stay in business requires being able to make lots of special modifications and shipments which takes some of the one-time set-up ideas out of the picture. Everybody wants something a little bit custom these days.

If it helps, we have experimented with modifying some tolerances of the broaches and offer those tools on ebay at a reduced rate. It's been pretty successful for those just getting started or not able to invest in the premium system. Hope that helps, *great rant*.

 

[kd0afk]

We manufacture rotary broach tools and I know what you mean about cost. However, the cost of business these days requires these prices to cover all the expenses. You mentioned the material, manufacturing, equipment, etc. and there's also the quality systems to insure consistency, packaging etc. - that added value adds some cost. Also, to stay in business requires being able to make lots of special modifications and shipments which takes some of the one-time set-up ideas out of the picture. Everybody wants something a little bit custom these days.

If it helps, we have experimented with modifying some tolerances of the broaches and offer those tools on ebay at a reduced rate. It's been pretty successful for those just getting started or not able to invest in the premium system. Hope that helps, *great rant*.

I don't buy your theory. Milling cutters have more machining, are held to tighter tolerances and I'm sure are quite a bit more involved than a rotary broach cutter. If they based the cost on your logic, a dovetail cutter would cost $5000.

 

[kd0afk]

You are correct doable . easy on a mill. there are tapered mill cutters for mold makers but the tapers are in the opposite direction of a dovetail .

you could use a lathe as a mill if needed.

Just use a hex collet block in a vise set a stop and lift the back end to create a 2 degree taper. just do the math like setting a sine bar.
Tin

In order to do all that I will need to devise a milling platform. If I have a jig that I word like to have made that will replace the tool post and have a 2 degree slope to it and a lip on the front edge for the stop. It will also have sides to register the block left and right. Clamping the block would be accomplished by a block that screws down over the block. The're is also an adjustment for height.
I will take machining on a mill to really do it right and anyone around here that has a mill I guess wants me to pay off their mortgage.
I could rig something that will work with clamps and shims and all but I want a fixture that will allow me to conveniently make a new cutter without an hour of set-up.

 

[Krutch]

Get a 3D printer!

 

[kd0afk]

Get a 3D printer!

And use it for what?

 

[Krutch]

And use it for what?

I should have been more specific.
If you don't like to do set-ups, the 3D printer is what you want. But then again, you have to make sure there is enough raw material for it to work, too.

 

[kd0afk]

I've decided to save my money and get a milling attachment.

 

[barnesrickw]

I've decided to save my money and get a milling attachment.

The only thing that I don't like about my milling attachment is the available travel. I'm working around that with some precision mounting blocks, but I still hope to get a mill some day.

 

[kd0afk]

On page 412 there is a mill & drill table. Would that thing work mounted horizontally? It has way more travel than I need right now I'm just wondering if it wouldnt work as a milling attachment?

 

[barnesrickw]

On page 412 there is a mill & drill table. Would that thing work mounted horizontally? It has way more travel than I need right now I'm just wondering if it wouldnt work as a milling attachment?

I've been trying to use those mill drill tables with the Ajax type thread. They seem to have no even measurement per turn, like 20 turns per inch, so it's hard to set to make measured cuts. Depending on your lathe, there are milling attachments for many available.

 

[kd0afk]

They're too expensive