Where Can I Get Thread Grinding Wheels?

[Wreck™Wreck]

The OP wanted to thread to a shoulder. A grinding wheel would have to be set at an angle to match the pitch of the thread. That wouldn't get to the shoulder.

Not really, thread milling is done with tools that are 90 Degrees to the work much like a lathe tool, relief angles are required.
The helix angle changes with thread lead and diameter, a thread lead of 10 TPI has a different helix angle at different diameters.

You will notice that one cutter will cut multiple leads as seen here.
https://www.mscdirect.com/product/details/40232878?fromRR=Y

 

[chips&more]

I did some thread milling. I remember it taking a very long time to set-up in my shop with what I have. But it did work out. All I have to show is the cutter. The job went to a friend. My recommendation is to find another way to do it. Sorry, but thread milling is not for everyone. It’s good to talk about and learn though.

 

[Downunder Bob]

Reverse threading will still require a thread relief or just the opposite action as pulling out while disengaging the half-nuts. I can't see diving into a spinning part to a precise point while the tool is traversing as practical. If you can use a relief instead of a close pullout, then conventional direction cutting is probably going to get you better results. besides, practice is good.

I agree.....everyone who has done much manual threading has had their share of crashes. The idea is that they get fewer as you go. Don't be afraid, it's happened to all of us. It's how we learned.

Exactly, the person who said they never made a mistake, never made anything.

 

[Tozguy]

Just a vote for turning the lathe by hand for tricky one-off threading jobs. First, your arm can go a lot slower than the motor.
Second, it is a lot easier to turn the spindle than you might imagine. You can feel the cut and adjust the d.o.c. or anything else to get a 'good' feel.
Third, no need for panic pills or other personal stress relieving procedures.

Actually, I recommend doing a threading job by hand early in the learning curve if only for the insights it might provide..

 

[4GSR]

For threading all the way to a shoulder. Imagine threading something with a really coarse thread, like this:

View attachment 211687

Maybe you have the lightning fast reflexes to disengage the half nut and back out the cutter before it crashes into the shoulder, but I don't have the confidence to try it. I'd much rather set my spindle on the lowest speed possible and engage the backgear, so the spindle rotates super slow while another tool (tool post grinder) does all the work.

I know your thread is focused on thread grinding on the lathe I presume.
My question is, Are you trying to go in and "doctor up" the thread on the spindle in your picture to clean up the buger marks? Or are you fixing to make a new spindle for your lathe?

 

[strantor]

I know your thread is focused on thread grinding on the lathe I presume.
My question is, Are you trying to go in and "doctor up" the thread on the spindle in your picture to clean up the buger marks? Or are you fixing to make a new spindle for your lathe?

I was asking myself the same question when I started getting alerts on this thread. "What the heck was I trying to do?" I don't remember. It was over a year ago; not that long ago, I should remember, but I don't.

 

[woodchucker]

I considered that, but it seems to me that if you can so easily form the grinding wheel, the grinding wheel will quickly unform itself when you start using it. So I was looking for a diamond brazed type wheel that doesn't wear away (as much).

No my plans are for the lathe. A tool post grinder angled to the thread pitch.

Quite often taps are ground with their threads, so it is very doable . Whether the hobbiest can afford the equipment is another question. I would expect CBN disks to be the choice due to the fine point on the stone breaking down too quickly. A cbn disk would stand up to more abuse. I would think they have a multiple wheels, coarse and fine to grind the taps.

 

[woodchucker]

I was asking myself the same question when I started getting alerts on this thread. "What the heck was I trying to do?" I don't remember. It was over a year ago; not that long ago, I should remember, but I don't.

Geez, I know the feeling.

 

[Ebel440]

Just reading this and remembered an old machinists handbook had some information about how to crush dress wheels for grinding. I don't remember what edition but it had a wartime supplement to the handbook so that should narrow it down. I cant remember much about what it said but I figured I'd put it in here in case anyone was looking for information.

 

[Downunder Bob]

Just reading this and remembered an old machinists handbook had some information about how to crush dress wheels for grinding. I don't remember what edition but it had a wartime supplement to the handbook so that should narrow it down. I cant remember much about what it said but I figured I'd put it in here in case anyone was looking for information.

From what I remember of crush dressing it requires a dressing wheel that is the mirror image of the profile required on the grinding wheel, in other words the same profile as the finished product. The dressing wheel is to a degree sacrificial as it will wear and will require replacement, but the process is quick, and therefor justified in high volume production. It requires some expensive and heavy equipment, and is generally only used when large production runs can justify the cost.

The only method I'm aware of that is applicable to hobby work is to use a single point tool, preferably diamond, to the dress the wheel as previously described.