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noyloj
11-01-2017, 08:01 PM
Hi there

Does anyone know if it's possible to manually cut a M10x1.5 thread into Chinese C7 1605 ballscrew with a die?

I haven't tried yet but it looks like super hard steel...

Otherwise I'm going to need to find a friendly machinist here in froggy land... rare indeed I should imagine in these mountains!

Ta

Jo

Neale
11-01-2017, 08:12 PM
Typically, the outside of these ballscrews is very hard, but the hardness is just a skin and the core is relatively soft. If you are talking about putting a thread on a plain end of a ready-machined ballscrew, then that would probably be OK (tough-ish steel but machinable) but I wonder why you would do this? Usually, this is where the pulley goes and you want that to be a close sliding fit on the ballscrew. A thread is most definitely not a good surface to bear on, and a thread cut by a die is very, very unlikely to be square to the shaft. OK for simple nut-and-bolt type work, but not if you are looking for accuracy/parallelism/concentricity, etc.

Some people talk about being able to turn the end of ballscrews with carbide tools and get under the hard skin; others soften the end first before machining. However, that is to turn the end down to the nominal 10mm or whatever, and if you are doing that then you would also be in a position to screwcut the thread on a lathe. A machine that justifies ballscrews justifies decent machining of those ballscrews or you are just throwing away accuracy.

But maybe you have something else in mind? Not sure what the real requirement is here.

Clive S
11-01-2017, 08:15 PM
Good luck with that. They can be done on a lathe. If you put a wet rag near the end and anneal it you just might do it. I am not sure without checking I thought they were M12x1

John S
11-01-2017, 08:17 PM
They can be screwcut with tipped tooling but I wouldn't fancy my chances with a die.

noyloj
11-01-2017, 08:27 PM
Thanks for the quick response...

I am doing a CNC conversion on a Warco WM16 and I'm following Hoss's design (more or less) I've had the screws machined in China but they neglected to put a thread for the Ballscrew retaining nuts on the Y axis... with this plan the 1605 screw is reduced to 10mm for bearings and then tapped at M10 x1.5 and finally reduced to take the motor coupler...

Hadn't even considered squareness to shaft...

noyloj
11-01-2017, 08:37 PM
Is squareness going to be a massive issue in this case the nuts only serve to retain the ballscrew in the fixed bearing holder?

Ta

njhussey
11-01-2017, 09:02 PM
the nuts only serve to retain the ballscrew in the fixed bearing holder?

Only?? Its what gives the ballscrew its rigidity and stops backlash etc. etc....needs to be square and true to put equal pressure all round on the bearing race.

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Neale
11-01-2017, 09:19 PM
Is squareness going to be a massive issue in this case the nuts only serve to retain the ballscrew in the fixed bearing holder?

Ta
As the man says, squareness is absolutely important. The bearings typically come with a retaining nut with an accurately (one hopes...) machined face specifically for this purpose. From memory, the nuts on mine didn't look like standard M10 - aren't they a much finer thread (like 1mm pitch, not 1.5?). Might be interesting to find a die of that size.

noyloj
11-01-2017, 10:13 PM
As the man says, squareness is absolutely important. The bearings typically come with a retaining nut with an accurately (one hopes...) machined face specifically for this purpose. From memory, the nuts on mine didn't look like standard M10 - aren't they a much finer thread (like 1mm pitch, not 1.5?). Might be interesting to find a die of that size.

Ok, though Hoss's plans don't specify any machining of the nuts in so far as I can see. I think he must rely on single point of contact being adequate to prevent axial travel since the bearings are held captive radially by the housing, but point taken the squarer the better!

Neil I agree... 1mm pitch would be much better as less material would be removed meaning easier cutting hopefully and I could buy lock/jam nuts specifically, good idea!

Perhaps if I set up my rotary table in the vertical position I could work out some way to hold the die somehow with the tailstock and allow it to slide forward as I turn the ballscrew in the chuck? Crazy or totally crazy?

komatias
11-01-2017, 10:36 PM
Ok, though Hoss's plans don't specify any machining of the nuts in so far as I can see. I think he must rely on single point of contact being adequate to prevent axial travel since the bearings are held captive radially by the housing, but point taken the squarer the better!

Neil I agree... 1mm pitch would be much better as less material would be removed meaning easier cutting hopefully and I could buy lock/jam nuts specifically, good idea!

Perhaps if I set up my rotary table in the vertical position I could work out some way to hold the die somehow with the tailstock and allow it to slide forward as I turn the ballscrew in the chuck? Crazy or totally crazy?

So if you are following the usual dimensions you will find the a M10x1.5 does not pass over the 8mm section. We typically use M10x1.0 as it also allows you to get a finer adjustment on the locking nut.

In answer to your original question, if you have rolled screws, then yes, you can use a die. I have done this with a M10x1.0 and as long as you are square on, you will be fine. You may need to use more lube than usual here.

noyloj
11-01-2017, 10:41 PM
So if you are following the usual dimensions you will find the a M10x1.5 does not pass over the 8mm section. We typically use M10x1.0 as it also allows you to get a finer adjustment on the locking nut.

In answer to your original question, if you have rolled screws, then yes, you can use a die. I have done this with a M10x1.0 and as long as you are square on, you will be fine. You may need to use more lube than usual here.


Thanks a lot! That's great news as I do have rolled ballscrews...

I knew if asked long enough someone would give me the answer I wanted!

Also my whack idea about the rotary table as screw cutting lathe ain't gonna work as the 2MT small end in the table is smaller than 16mm...

So carefully by hand with plenty of lube it is... sounds familiar!

Clive S
11-01-2017, 10:51 PM
I knew if asked long enough someone would give me the answer I wanted!
That's the trouble if you ask enough people you will eventually get the answer to want to hear.

noyloj
11-01-2017, 10:58 PM
That's the trouble if you ask enough people you will eventually get the answer to want to hear.

Well our man Komatias has actually done it... soooo.... I'm gonna have to give it a shot!

Thanks everyone I'll let you know how I get on in my build log if I ever manage to find a M10 x 1mm HSS die in the wilds here!

Jonathan
11-01-2017, 11:00 PM
Post it to me with the nut you want to use and I'll cut the thread on my lathe for the price of return postage.

Edit: Sorry I'm retracting that offer - I don't think this will help you as much as it might at first appear.

John S hit the nail on the head with "They can be screwcut with tipped tooling but I wouldn't fancy my chances with a die.".

John S
11-01-2017, 11:15 PM
Because John S has done it hundreds of times with his own compact design for mounting the motor, bearing, nut and coupling.

http://www.stevenson-engineers.co.uk/files/x3xaxis.jpg

Patented that is as well.

No sticking the motor on two plates and 4 pillars. Its a CNC machine not a fcuking clock.

komatias
12-01-2017, 07:50 AM
No sticking the motor on two plates and 4 pillars. Its a CNC machine not a fcuking clock.

AMEN!

Now, guys, remember, the conversion is done on the cheap and the expectations will be of the same order of magnitude.

Would I die cut again? Nah, I would just buy machined ballscrews and be done with it.

njhussey
12-01-2017, 08:18 AM
AMEN!

Now, guys, remember, the conversion is done on the cheap and the expectations will be of the same order of magnitude.

Would I die cut again? Nah, I would just buy machined ballscrews and be done with it.

In fairness to the OP he did say that the Chinese forgot to do the thread when they machined the ballscrew....he's just trying to fix it as cheaply as possible with the tools he has 😊



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noyloj
12-01-2017, 05:33 PM
Because John S has done it hundreds of times with his own compact design for mounting the motor, bearing, nut and coupling.


Patented that is as well.

No sticking the motor on two plates and 4 pillars. Its a CNC machine not a fcuking clock.

Yes, that is a thing of beauty! I was thinking of a couple of bits of machined 4" x 2" angle ally machined up to form a square pr possibly welding up a few plates into a box kinda like the Damon CNC solution... Buerk! Clumsy in comparison but hopefully enough to get me to a position where I can CNC machine a neater solution...

noyloj
12-01-2017, 05:35 PM
Post it to me with the nut you want to use and I'll cut the thread on my lathe for the price of return postage.

Edit: Sorry I'm retracting that offer - I don't think this will help you as much as it might at first appear.

John S hit the nail on the head with "They can be screwcut with tipped tooling but I wouldn't fancy my chances with a die.".

Thanks anyhow, but I've gone ahead and bought the die already on ebay... Looks like Old Skool rules for me!

fifa
22-02-2017, 09:05 PM
Depends how good you are.



Material is not a problem it is not "superhard", it peeled and rolled thread, typically St 52 , surface is hard due plastic deformation

Core is relatively soft. the best method would be to use the lathe, but it shall not be a problem to do it manually presuming you will use proper oil and non-chinese die ...

regards