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M42 toolbits

I'm new to machining & tools.

I have a myford lathe that I bought a couple of yrs ago and I've been playing occasionally. I now need to make a 'real' part to fix the mower. Basically a rod with threads on each end, one is a LH thread. Yep I could buy a new part, but that would be to easy!

So I went to local tool store, who didn't have much of anything let alone things I thought I wanted ( I thought I wanted some of those carbide tipped tools). But I did buy 2 x M42 1/4 x 2.5" 8% cobalt toolbits which where the only toolbits they had (OK not much of a tool shop I know, but it was sat morning & it was best I could find.)

To cut my thread I know I need to make a 60deg tool. But these toolbits I bought seem to good & sharp for me to start grinding them!

So before I do, I'm wondering, are they designed & made to be used "as is"? Should I be making my 60deg tool out of some HSS I got with the 2nd hand lathe? or should I just buy some of those carbide replacement tip tools from ebay & save the M42's for something else later on?

Thanks for any help getting a begineer started.

Reply to
dot
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Grinding them yourself is the usual way.

It will likely take you a bit of time to get the 60 deg. you want even if you have a decent grinder.

Also, best if you have one of those 60 deg center gages to make sure you have your 60 deg. and not 58 or...

If you don't fancy grinding the blanks yourself, check ebay. They often have small lots of them for sale. Luck of the draw says that you will end up having to grind some of them to the shape you want though.

There are also a variety of threading toolholders that you can buy. They can make life easier but you run up the cost and ruin the learning experience.

Hope that helps.

DOC

Reply to
DOC

Go for it. THe M42 will be more forgiving than carbide, easier to grind, easier to get a real sharp edge.

Nothing like the sound of a ten-dollar carbide insert going "snap" or "rumble" as it makes the transition toward uselessness...

at dot wrote:

Reply to
Mark

I'd suggest you need a good textbook on how to machine. I'd heartily reccomend my shop text from 20 years ago. it was also used when my son went for his machine shop degree.

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"Machine Tool Practices" has a great section on how to grind your own tool bits, lots of pictures. There will be another section on how to thread on a lathe.

I'd just buy a used book. Use the money you save to buy more tooling.

Good Luck

Karl

Reply to
Karl Townsend

You need to know more about grinding tool bits before you start in on threading bits. They are somewhat more finicky, what with the clearance angles required. The coarser the thread and the smaller the diameter, the more you have to worry. And, a bit for LH threads is different from one for RH threads.

It's more complicated than just grinding a 60 degree point.

You can buy tool bits ground ready for use or with just the end ground to a square bevel. You'll have to decide which you have.

John Martin

Reply to
John Martin

A 2" diameter M42 end mill contacting a vise jaw has that sound beat by a mile ;-)

Indexable tooling is a wondrous thing.

Reply to
Tim Killian

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