Need assistance with a M60x3 spindle protector/nut

[lSherlockl]

Have a old grizzly 12x36 lathe

wanting to use a collet closer setup on it and need a nut/thread protector to protect spindle threads (DIN 800 spec) and help pop the mt5 collet adapter out when needed.

thinking a 46MM ID opening at the front of nut (have enough clearance on the mt5 taper on the collet adapter have 37mm of threads and collar some external grooving or index hole to mount a wrench or something to provide some force.

should be fairly basic, I know i could probably make one but i don't have the tooling for a 3mm thread much less internal with a stop at the front is a little spooky for my skillset.

 

[Alexander McGilton]

A little something like this?

Hardest part is not making the product itself, but the go no-go gauge to calibrate ones machine to. Example is for an M47x4 thread.

 

[WobblyHand]

Have a old grizzly 12x36 lathe

wanting to use a collet closer setup on it and need a nut/thread protector to protect spindle threads (DIN 800 spec) and help pop the mt5 collet adapter out when needed.

thinking a 46MM ID opening at the front of nut (have enough clearance on the mt5 taper on the collet adapter have 37mm of threads and collar some external grooving or index hole to mount a wrench or something to provide some force.

should be fairly basic, I know i could probably make one but i don't have the tooling for a 3mm thread much less internal with a stop at the front is a little spooky for my skillset.

Recommend threading away from the chuck. Then the pucker factor is greatly reduced. You would need to use a left hand tool, or use a right hand tool upside down. A 3mm thread is just under 8 TPI, so things move along quickly. All the more reason for threading away from the chuck. Remember, with nearly all metric threading you cannot disengage the half nuts, or you will loose sync. So the half nuts need to be engaged the entire time. (If you loose sync, it's a slight pain to resync, but not terrible.). Since the part is relatively short, you could retract the tool and turn the spindle by hand until you are at the start of the thread groove. Then put the tool in the cutting position, and turn on the lathe so the tool cuts while the carriage is going towards the tail stock. Once the pass is done, turn off the motor and repeat the process. After a while you are done.

It's not as hard as it seems. Even I can do it. I only started at machining three years ago. I made a back plate for my lathe out of a raw piece of cast iron, including the 8 TPI threads. Just run the lathe at the slowest RPM, do some air cuts to get an idea of the process, and then jump in, head first! Honestly, it really is the only way to learn - by doing. By the way, that back plate came out just fine - even though it was scary and half the time I was doubting I could do it. Just take care, take good measurements, and things should go well!

Here's something similar in nature, a spider I made. Inside threading, metric, M39x1.5, away from the chuck. Same thread gutter, same technique as mentioned above. Left hand bar, top notch insert. A little smaller than what you have, but the same idea. Done on a Grizzly G0752Z/G0602 10x22. Spider mounted on the 10x22. Made the brass tipped screws as well (not in this picture). You can thread, just about anyone can. It takes a little practice, but then it becomes second nature.

 

[Ischgl99]

I can make it for you, but it would be a lot cheaper for you to buy the tooling and try yourself. I would need to make a go/no-go gage, that would significantly increase the price, you could use your spindle nose to test the fit by removing the chuck and trying the workpiece on the spindle threads without removing it from the chuck.

 

[lSherlockl]

Recommend threading away from the chuck. Then the pucker factor is greatly reduced. You would need to use a left hand tool, or use a right hand tool upside down. A 3mm thread is just under 8 TPI, so things move along quickly. All the more reason for threading away from the chuck. Remember, with nearly all metric threading you cannot disengage the half nuts, or you will loose sync. So the half nuts need to be engaged the entire time. (If you loose sync, it's a slight pain to resync, but not terrible.). Since the part is relatively short, you could retract the tool and turn the spindle by hand until you are at the start of the thread groove. Then put the tool in the cutting position, and turn on the lathe so the tool cuts while the carriage is going towards the tail stock. Once the pass is done, turn off the motor and repeat the process. After a while you are done.

It's not as hard as it seems. Even I can do it. I only started at machining three years ago. I made a back plate for my lathe out of a raw piece of cast iron, including the 8 TPI threads. Just run the lathe at the slowest RPM, do some air cuts to get an idea of the process, and then jump in, head first! Honestly, it really is the only way to learn - by doing. By the way, that back plate came out just fine - even though it was scary and half the time I was doubting I could do it. Just take care, take good measurements, and things should go well!

Here's something similar in nature, a spider I made. Inside threading, metric, M39x1.5, away from the chuck. Same thread gutter, same technique as mentioned above. Left hand bar, top notch insert. A little smaller than what you have, but the same idea. Done on a Grizzly G0752Z/G0602 10x22. Spider mounted on the 10x22. Made the brass tipped screws as well (not in this picture). You can thread, just about anyone can. It takes a little practice, but then it becomes second nature.
View attachment 504205View attachment 504209View attachment 504210

I can make it for you, but it would be a lot cheaper for you to buy the tooling and try yourself. I would need to make a go/no-go gage, that would significantly increase the price, you could use your spindle nose to test the fit by removing the chuck and trying the workpiece on the spindle threads without removing it from the chuck.

could either of you direct me to what tooling or term I should be looking for, to cut those internal threads? i know it should be a 60 deg thread taper and 3mm spacing. but i cant find any well "more beefy" thread cutters in my searching so i guess im looking for the wrong thing. and all i got is a muuuuuuch tooo small internal thread cutting bar

 

[SWIGIN]

For internal threading I always used an old school boring bar with HSS on the 90 degree end.

 

[Ischgl99]

There are several options, a boring bar with a ground HSS tool as swigin mentions is probably the cheapest way to go. You can also get brazed carbide threading tools to use in boring bars if you are not good at grinding an accurate angle on the tool. Something like this https://www.micro100.com/products/brazed---threading-tools---er-style. You may need to grind a radius on the under side of these tools to get them to fit in the internal hole without rubbing and cut down the shank to fit your hole.

A lot of people here like using carbide inserts. The most common types are laydown inserts and the Kennametal Top Notch style insert. The attached documents show the laydown style bars and inserts. If you are threading conventionally from right to left, for an internal thread, you would need a bar with the part number starting SIR. If you are threading in reverse, you need the left hand bar with part number starting SIL. I would get the largest bar your toolholders can use, that will get you the most rigidity. The 16 size insert can cut a large number of thread sizes when using the AG partial profile style and can do your 3mm thread down to 0.5mm. If you can use a maximum bar size of 1/2” for example, the left hand threading bar would be SIL0500M16. The 0500 is the bar size and M16 is the bar length and insert size.

I’m not as familiar with the Top Notch system, someone else here that uses it can give you the details on that, but in general it is the same thing. You will need to select an insert that is big enough for your 3mm thread, and then find the tool holder that fits. You would need a left hand tool if you are threading away from the chuck just like with the laydown inserts described above.

Another option is a ground carbide tool. These are a bit pricey, but very good and rigid. The downside is they are easy to break. If you chip it, or are careless and hit a shoulder, you’ll need to buy another one. Micro100 makes excellent tools. You can select the size you need on this page. https://www.micro100.com/products/standard---threading-tools---un-threads---single-point---left-hand They also make brazed carbide versions of these, I haven’t used them, but would expect them to work well and wouldn’t be as fragile as the solid carbide type, but the tip can still be easily chipped.

 

[WobblyHand]

I've made a boring bar/threading tool out of a steel rod. I then cross drilled it through. Then installed a set screw. I bought some 3/16" HSS and ground the tool to threading profile. The nice thing about the tool was that I could make it a right hand or left hand tool simply by removing the HSS and installing it from the other side. The bar is easy enough to make so one could make multiple sizes (diameters) with appropriate scaling. All steels have the same rigidity, so you can make it out of nearly whatever you can source. What matters for a bar is it's diameter. Hardness can be desirable, but hardness is not the same as rigidity. For a boring bar it's all about rigidity, the ability to resist bending.

I also have a left hand Kennametal threading bar, it's 3/4" in diameter. It fits in an AXA boring bar holder. Think it is a A12NEL2. The "L" denotes a left hand tool. I bought it used off eBay. You will need to get some threading inserts to match the bar. To maintain rigidity, you should use the largest bar that fits in the hole and has enough clearance. Using a skinny undersized bar can lead to chatter in your threads, I have learned this the hard way.

Hope this helps some. Not so long ago, I had many of the same questions.

One last thing. On this site, there are several excellent threads on these kinds of things, a wealth of knowledge here on Hobby Machinist. It's worth spending a couple of hours reading them. I can especially recommend Mikey's threads on grinding High Speed Steel (HSS) tools and on Boring. Mikey (RIP) was a class act and really tried to help beginners. I learned a lot from him.

 

[Alexander McGilton]

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

This tool should be good for the thread. If not buying it. Simply copy the design off of the demiensioned drawing by grinding a 1/2 inch HSS blank tool.

 

[WobblyHand]

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

This tool should be good for the thread. If not buying it. Simply copy the design off of the demiensioned drawing by grinding a 1/2 inch HSS blank tool.

That's a right hand tool. It can be used for threading away from the chuck if turned upside down.