Milling a helix

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

Moderators: Harold_V, GlennW

Harold_V
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Re: Milling a helix

Post by Harold_V » Thu Jun 07, 2018 3:22 pm

Multiple start, or very large diameter. In any case, it requires a degree of skill (to avoid a crash) that most likely is beyond my level, especially now, as I'm no "spring chicken". The one saving grace might be that the worm has ample clearance on both sides, so pulling out at the appropriate moment wouldn't be an issue as it was when I created a 3 pitch auger for my wife's wheat grinder several years ago. In that instance, I had to start in a groove, and pull out at the prescribed moment. A very taxing operation, especially considering the huge amount of tool in contact with the part. Pulled it off, though.
Here's a picture.
Auger5.JPG
Part was made of 17-4PH and heat treated to H900 after machining, thus the color.

A milling attachment for such a large thread would likely be to advantage, assuming it could be set at the helix angle. Without that ability, it really couldn't be used unless one emulated what I'll do (not use a side cutter)---keeping the cutter dead on center, so the desired form isn't altered.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

RSG
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Re: Milling a helix

Post by RSG » Thu Jun 07, 2018 4:36 pm

Harold_V wrote:
Mon Jun 04, 2018 11:52 pm
RSG wrote:
Mon Jun 04, 2018 9:27 am
Lets see more pics Harold!
Anything particular? I'm happy to comply, but I didn't want to post a bunch of things that others might not find of interest.
H
Nothing particular, just the whole set up :lol: I'm sure no one here will find it boring.....maybe the milling in action, perhaps a short video of it cutting would be lovely....if you are so incline :wink:
Vision is not seeing things as they are, but as they will be.

K. Brouwers
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Re: Milling a helix

Post by K. Brouwers » Sat Jun 09, 2018 3:21 am

Hello Harold,
I think you have the facilities to generate a accurate angle block sitting on your shop floor. :wink: I would think your CNC would be accurate to cut any angle you might need. simply cut a plate of what you have laying around set it on your mill and align with your indicator. I did the same a few years ago wondering how to get close in a setup when it finally dawned on me that I had the solution on my floor too.. :lol: :lol:
Cheers Karel
PS thank you very much for your efforts on the board...

Harold_V
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Re: Milling a helix

Post by Harold_V » Sat Jun 09, 2018 5:06 am

Karel,
A heavy sigh!

Just yesterday, for reasons I can't address, I thought I'd fire up my CNC, just to see it run, as it hasn't been operated for more than a year. I was shocked to find it DOA. After a little exploration, I found two blown fuses, and two indicator lights lighted, telling me I need to call for service.

The indicator lights tell me that there's a problem with a voltage spike, which I now fear is related to the induction furnace blowing a fuse on the primary line, leaving the CNC single phasing. While it wasn't turned on, the main power switch was on, so the power supply must have been receiving at least some voltage. Now I must face the possibility of a repair that is beyond my financial ability----one of the reasons I had hesitated to get involved with CNC equipment. I'll give Haas a call in the near future and try to determine where I stand.

So then, while you're suggestion may have born fruit, it won't help me right now, but then the setup I'm building looks very promising, and will serve the purpose just fine. A little playing with the angle and all should be good, and I'm retired, so time means little to me anymore, so long as I'm engaged in something I'm enjoying, and this project fits that bill quite nicely. Just wish I still had the keen edge I had when I was actively machining those many years ago.

Thanks for your comments! They're appreciated.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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GlennW
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Re: Milling a helix

Post by GlennW » Sat Jun 09, 2018 6:12 am

I've found mine DOA any time it sits unused for any extended period of time.

The new deal is to run it at least every couple of weeks, even if only to run it through it's start up cycle.

The start up cycle is one that I created where you give a few pulls on the lube plunger, reference the axes, and then run a quick program that takes it through it's travel limits and then parks with the spindle over the vise datum or other pre-determined location.

I created it mainly to spread lube on the ways but it's good exercise for the machine!
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

K. Brouwers
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Location: Philippines

Re: Milling a helix

Post by K. Brouwers » Sat Jun 09, 2018 7:05 am

Ouch,
It's painful to hear about a dead CNC. I used to have a Fanuc GN5 comtrol built in 1977 an old dinosaur for sure on my router and had the battery go dead because of its being in storage for a while,I replaced the original very small battery with ordinary rechargeable cells of the same voltage they they hold much more charge. The problem was reloading the parameters luckily I had all the documentation. perhaps it might be only the blown fuses and a dead battery hopefully.
I think I can't reply cheers here. But does good luck sound OK?
Karel

John Hasler
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Re: Milling a helix

Post by John Hasler » Sat Jun 09, 2018 7:53 am

Single phasing with no motors running should not have harmed the electronics but the spike may have. It's possible that the fuses did their job and protected the machine from further damage. I'd determine what the fuses protected, inspect for visible damage, and if I found none replace the fuses and try again. Are the fuses in the AC side? Do you have documentation?

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Richard_W
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Re: Milling a helix

Post by Richard_W » Sun Jun 10, 2018 11:18 am

Harold_V wrote:
Thu Jun 07, 2018 3:22 pm
Multiple start, or very large diameter. In any case, it requires a degree of skill (to avoid a crash) that most likely is beyond my level, especially now, as I'm no "spring chicken". The one saving grace might be that the worm has ample clearance on both sides, so pulling out at the appropriate moment wouldn't be an issue as it was when I created a 3 pitch auger for my wife's wheat grinder several years ago. In that instance, I had to start in a groove, and pull out at the prescribed moment. A very taxing operation, especially considering the huge amount of tool in contact with the part. Pulled it off, though.
Here's a picture.

Auger5.JPG

Part was made of 17-4PH and heat treated to H900 after machining, thus the color.

A milling attachment for such a large thread would likely be to advantage, assuming it could be set at the helix angle. Without that ability, it really couldn't be used unless one emulated what I'll do (not use a side cutter)---keeping the cutter dead on center, so the desired form isn't altered.

H
I have not had the opportunity to cut multiple starts that have a lead of several inches on a lathe. With that being said one of the guys I worked with did just that. He was doing it on a 20" swing German built Martin lathe. He told me that when doing diametrical pitch that instead of the spindle turning the lead screw, the lead screw turned the spindle on that lathe. He was a retired navy chief in charge of ships machine shop and had done a lot of things over the years. That being said couldn't you reduce the motor speed on your lathe using a frequency drive inverter? This would slow the spindle down to manageable speeds to engage and disengage the half nut. Or is my thinking off on this.

Richard W.

Harold_V
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Re: Milling a helix

Post by Harold_V » Sun Jun 10, 2018 3:26 pm

K. Brouwers wrote:
Sat Jun 09, 2018 7:05 am
Ouch,
It's painful to hear about a dead CNC. I used to have a Fanuc GN5 comtrol built in 1977 an old dinosaur for sure on my router and had the battery go dead because of its being in storage for a while,I replaced the original very small battery with ordinary rechargeable cells of the same voltage they they hold much more charge. The problem was reloading the parameters luckily I had all the documentation. perhaps it might be only the blown fuses and a dead battery hopefully.
I think I can't reply cheers here. But does good luck sound OK?
Karel
Anyone's kind thoughts are welcome, and comforting.
Two fuses were blown, so I tried replacing them. The first one replaced held, but when the second one was replaced, both blew again. I am now down to only one spare, all of which were included in the machine near the position in which they are used. I'll have to buy new fuses when I begin the process of trying to determine where the problem lies.

I expect I'll need a little luck---I'm not a technician, but I am one hard headed, determined individual, and fully intend to get this machine back in operation (or i's out of here. It's taking up a large piece of shop space), although I am not in a hurry.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Harold_V
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Re: Milling a helix

Post by Harold_V » Sun Jun 10, 2018 3:31 pm

GlennW wrote:
Sat Jun 09, 2018 6:12 am
I've found mine DOA any time it sits unused for any extended period of time.

The new deal is to run it at least every couple of weeks, even if only to run it through it's start up cycle.

The start up cycle is one that I created where you give a few pulls on the lube plunger, reference the axes, and then run a quick program that takes it through it's travel limits and then parks with the spindle over the vise datum or other pre-determined location.

I created it mainly to spread lube on the ways but it's good exercise for the machine!
The Haas TM-1 has only four lube points, all of which are grease fittings. Unusual construction, intended to be fully renewable, and seems to be up to the task. No plunger to pull (I use a grease gun) with lubrication intervals with quite widely spread. As for a start up cycle, the machine has one, and it knows if it hasn't been operated. Takes about 20 minutes to execute, as I recall (it's been a long time since it was last operated).

Interesting that your machine doesn't run if not operated regularly. What does it do, Glenn? Mine simply did nothing at all!

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Harold_V
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Joined: Fri Dec 20, 2002 11:02 pm
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Re: Milling a helix

Post by Harold_V » Sun Jun 10, 2018 3:41 pm

Richard_W wrote:
Sun Jun 10, 2018 11:18 am
I have not had the opportunity to cut multiple starts that have a lead of several inches on a lathe. With that being said one of the guys I worked with did just that. He was doing it on a 20" swing German built Martin lathe. He told me that when doing diametrical pitch that instead of the spindle turning the lead screw, the lead screw turned the spindle on that lathe. He was a retired navy chief in charge of ships machine shop and had done a lot of things over the years. That being said couldn't you reduce the motor speed on your lathe using a frequency drive inverter? This would slow the spindle down to manageable speeds to engage and disengage the half nut. Or is my thinking off on this.
I spent almost my entire machining career operating small machines, as my specialty was small work (I have a lot of patience when operating a machine tool, unlike the balance of things I do in life). That said, while I've operated larger equipment, I don't have a lot of experience doing so.

I am familiar with the concept of driving the machine through the lead screw, which most likely would be a solution to the problem, but on small machines like mine, the ratios required are not necessarily at one's disposal. I had to alter the gearing on the Graziano to create the three pitch lead I needed for the auger for the wheat grinder, which was the maximum lead I could create. The original auger had a much greater lead, but the three pitch seems to work just fine, especially now that I power the hand driven wheat grinder by using the Graziano. It's easy to turn, but the repetitive action gets old in a hurry.

As far as powering the lead screw, that would be a difficult task to accomplish on the Graziano, although certainly not beyond possibility.

A VFD might offer a solution, although getting the machine to run slow enough, even if I could create the necessary lead, would likely result in reduced oil pressure, causing the machine to quit operating. It has a pressure switch that prevents operation under low oil condition, and I expect that the reduced pump speed would result in lowering of pressure. The machine already has a two speed motor (not common for the Sag 12, but I ordered mine with a two speed motor, which they gladly provided, although at additional cost), and it's obvious that the pump runs slower. Much more pleasant sound than at full speed.

Thanks for your thoughts, Richard.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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GlennW
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Re: Milling a helix

Post by GlennW » Sun Jun 10, 2018 3:47 pm

Harold_V wrote:
Sun Jun 10, 2018 3:31 pm
Interesting that your machine doesn't run if not operated regularly. What does it do, Glenn? Mine simply did nothing at all!
It seems to have various issues. The most recent, nothing on the control panel would operate and the coolant pump started running as soon as power was applied. Before that, the processor board failed. One other time one of the servo amps failed. Once the display failed.

1995 era electronics in a hot and humid environment.

It's great fun!

I'm kind of in the same boat as you, as it becomes an expensive pile of scrap iron if you don't keep putting money into it...

Mine has an automatic way oil lube system that incorporates a manual plunger.

Glenn
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

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