[DarkStarMedia]

So... I wanted to start a separate thread to document the re-build of this IH mill I got. I also plan on using this as a log to remind myself what I did and why I did it, so forgive a bit of rambling...

Lets start with a bit of history.

I purchased this mill (a 2005 model) used. It has very little wear.

As purchased it had the R8 spindle and stock tapered roller bearings. It also came with the NT30 spindle that was sold in the past for $65and a 2HP VFD drive through the gearbox.

My planned eventual upgrades include the following:

One shot oiling for the ways and ball screws
Tool changer
2 speed Belt drive
Max spindle RPM 6000-9000 (no gearbox)

But first tings first get it up and running and making money.

As purchased it had the following obvious issues.... first, a couple of the Z axis limit switches are broken and I could not rotate the spindle with my hand and it seemed rough with a wrench.

That last item might be due to low use but I don't know.

First item: Swap the spindle and bearings.

Instead of simply replacing the bearings with another set of tapered roller I decided to go to AC (angular contact) bearings. This will allow me to get into my 6000-9000RPM range once I swap to belt drive.

Taking the quill out of the head is fairly simple. There is one catch though... there is a set screw that limits the downward movement of the quill. You have to remove it but there is a second set screw below the first set screw (thank you Tommy).

Also, another issue I ran into is that the spanner nut on top of the spindle that holds everything together is different from the R8 spindle to the NT30 spindle. The R8 has a 1.5mm pitch while the NT30 has a 1.25mm pitch.

Another call to Tommy indicates that this is no longer the case.... off to MSC.

I wanted to take a moment to comment about IH support. I do much of my work during off hours as I have to keep a day job till things pick up. Every time I have run into an issue and have had to call IH, Tommy has picked up the phone or called me back in minutes... on Saturdays and Sundays.

I know some have had issues with service at IH but I have not. And lets remember that I have never purchased anything from them. The mill was originally a manual mill that an IH kit was put on.

I have tried to purchase something from Tommy (limit switches) only to be told to send him and email and he would give me part numbers for the parts he uses.


That is all for now!

Richard

[DarkStarMedia]

The plot thickens.... the nut is either 20TPI or 1.25mm pitch.

The problem is in metric or inch there is no standard thread in the size range that includes the diameter.

I figure it's either a 30mm or a 1 1/8 thread. I measured the threads and the best i can tell the minor diameter is 1.120-1.125in and the major diameter is right near 1.150 in.

I think I might have to have a custom nut made....

This doesn't make sense... I am fairly sure that IH didn't have this thing custom made... anyone have a contact with the old owner?

Richard

[RustedOut]

The nut is called a bearing nut or precision lock nut and they all have special threads. McMaster carries them in the American National Special or Unified Special thread sizes. The latter link provided threading information, but there are other thread sizes as well, just look around but I think you'd be interested in the sizes linked and it relates to the PN series of nuts.

Whittet-Higgins web site has a lot of info on these type of products, but I'm not too sure you can order from them. I just found what I needed there and asked them where I could buy their products local and got a good answer.

I found my ER32 collet spanner wrench fits the original IH R8 nut and the new nut I bought for my belt drive conversion.

Bob

[DarkStarMedia]

The nut is called a bearing nut or precision lock nut and they all have special threads. McMaster carries them in the American National Special or Unified Special thread sizes. The latter link provided threading information, but there are other thread sizes as well, just look around but I think you'd be interested in the sizes linked and it relates to the PN series of nuts.

Whittet-Higgins web site has a lot of info on these type of products, but I'm not too sure you can order from them. I just found what I needed there and asked them where I could buy their products local and got a good answer.

I found my ER32 collet spanner wrench fits the original IH R8 nut and the new nut I bought for my belt drive conversion.

Bob

thank you for that... Unfortunately none of them seem to be available in 20tpi or 1.25mm pitch.

that does give me a very good lead though.

Richard

EDT: I did find that Porsche used a m30 x 1.25 nut in one of their trannys... I am going to order one on Monday to see if it fits.

[RustedOut]

You don't say what state you reside in, but Motion Industries is in a lot of them. That's where I got the nut I bought. Take you spindle in there if you have one local and they most likely can accommodate you.

Bob

[DarkStarMedia]

I am in southern Arizona... near Tucson for much of the year.

Richard

[DarkStarMedia]

Well... Just an update, I ended up just getting a new 30 taper spindle from IH.

It came with the nut (same as the R8) and went in just fine. I am now back from my cousins wedding and am getting back to it.

I ran into some drive issues but I now have the machine moving and will be squaring it up and getting it ready.

Hopefully I should be making some chips this weekend.

Richard

[DarkStarMedia]

So... as usual just when you think you are almost there... you get kicked in the face..

Well, I got my drive issues figured out... mostly. I contacted Artsoft about getting the license transferred to my name (as opposed to the PO) only to find out that the licenses are not transferable.. grr. So, I made sure it was in demo mode. I care about these things.

I was planning to purchase a license for Mach3 but I am having second thoughts as I think the non-transferable policy is somewhat unreasonable.

I may try LinuxCNC\EMC2... haven't decided yet.

Other things on the list to fix is the control was built with the fault line on the Gecko shorted to the 5v line for the encoder. I have to figure out to get those working and signaling the computer.

None of those are show stoppers... but....

While squaring the head the z axis motor started stalling and I noticed the ball screw was jumping up and down as the drive continually re-set.

This was caused by a problem with the gib not staying where it should... and now I have to pull the head to see what up. The slide is an older style that doesn't have a retaining screw on the bottom to retain the gib.

So what happened is the head moved up but the gib didn't and that bound up the head.

in this version I think the gib is supposed to have a slot that the upper screw rides in, but the top of the gib broken off.

Given that the bottom of the slide casting is broken off (meaning only the two side bolts hold the head from rotating). I talked with Tommy at IH, who called me back on Labor day (Thanx again Tommy), and he said that he might have a replacement slide casting (newer style) lying around and he would check today.

Richard

:banana:

[DarkStarMedia]

So... I figured an update might be in order.

I got a new style head and slide (wide style) from tommy (again great support from him) and was able to install both on my current column.

I had the slide milled for oiling grooves and I drilled out the ball oilers (which were painted over) and and tapped 1/8 npt for Legirs fittings.

Because the distance from the back of the slide changed a bit, not much but enough to bind the ballscrew at the top. So I rotated the ballscrew mount 90 degrees so that the motor is behind the column and re-drilled and tapped new holes.

It works marvelously.

I also installed a belt drive from Dave (arizonavideo) and it is well worth it.

So the Z axis is nicely buttoned up.

While I was squaring the head I started measuring runout. I have about half a thou runout in the spindle (how average is that for this machine?). I am not sure there is anything I can do about it.... I already have AC bearings.

When I put a shars ER40 NTMB30 tool holder this jumped to about 1.5 thou. A little disappointing for a collet holder. I will be sending an email to Shars about it.

I am thinking about trying to get at least one high end tool holder to see if it's any better.

On a sadder note I found that the y axis has too much backlash. I narrowed it down to a lousy ballnut mount. I am going to have to take it apart and machine the bottom of the saddle and do it right.

The current ballnut mount is only held on by 2 screws and the other side hangs over the back side of the saddle so it is flexing.

This likely wasn't a big issue for the PO because he set the gibbs looser than I want so there was less stress on the ballnut mount.

Anyone know how the ball nut is affixed to the ballnut mount?

Richard

[Mike Nash]

From the instructions for Y-axis assembly from waaay back:

Locktite the ballnut, a few drops only.
Although the tip is green, it is equivalent to Locktite "Blue"
Tighten it up.
Put in the setscrew.

[DarkStarMedia]

From the instructions for Y-axis assembly from waaay back:

Locktite the ballnut, a few drops only.
Although the tip is green, it is equivalent to Locktite "Blue"
Tighten it up.
Put in the setscrew.

So the outside of the ballnut is threaded and it just unscrews after removing the set screw?

Thanx! any thoughts on what normal spindle runout is?

Richard

[Mike Nash]

If it was the Aaron Moss kit yes, I believe so. However, it was supposed to have Locktite on the threads and be tightened with Vise-Grips before installing the setscrew. I have the manual mill, but I don't have the kit.

And no idea on runout.

[Runner4404spd]

your spindle runout should be less than .001 on the taper. most companies that build precision spindles will regrind the taper once the bearings are installed and the spindle housing installed in its assembly.

[DarkStarMedia]

Another update is in order... I have it mostly running but I am dealing with some backlash issues.

also, I am having trouble configuring the pulley ratios in mach... It seems that changing the ratio box in the pulley config screen does nothing I have no idea why.

for now I am going set the motor tuning so it is accurate in low speed and leave it there so I can use it.

I have the one shot setup without flow valves so it is a bit of a mess and I have to over oil some areas to be sure everything gets oil but it will get me running.

I still need to find some workbench mat material for way covers...

richard

[DarkStarMedia]

yes... It has a variable speed motor.... Are you asking a question?

richard

EDT: I guess the post got deleted...

[saabman]

What I suggest is that you set your VFD at 60 hz when setting the pulley ratio. Get yourself an rpm scan tool and put a marker on the top of the spindle.

Once you have the VFD set, you should be able to put 6 pulley sizes in Mach. Mach uses the pulley size as a baseline mapping between the voltage/pwm it is sending to get the VFD to run at 60 and the speed pulley rpm you are calibrating it to.

Now pick a gear and sync the pulley setting in mach. Go to the spindle control, bump the RPM up 50% and observe your VFD freq. It should be 90 hz (or there about). Bump it down 50%, the hz should be 30.

The last thing is to use the scan tool to verify the spindle speed mach is commanding with the actual speed of the spindle.

I went as far as to adjust one of Machs tables to get very nearly linear response from mach and the VFD.

[DarkStarMedia]

What I suggest is that you set your VFD at 60 hz when setting the pulley ratio. Get yourself an rpm scan tool and put a marker on the top of the spindle.

Once you have the VFD set, you should be able to put 6 pulley sizes in Mach. Mach uses the pulley size as a baseline mapping between the voltage/pwm it is sending to get the VFD to run at 60 and the speed pulley rpm you are calibrating it to.

Now pick a gear and sync the pulley setting in mach. Go to the spindle control, bump the RPM up 50% and observe your VFD freq. It should be 90 hz (or there about). Bump it down 50%, the hz should be 30.

The last thing is to use the scan tool to verify the spindle speed mach is commanding with the actual speed of the spindle.

I went as far as to adjust one of Machs tables to get very nearly linear response from mach and the VFD.

So, the procedure I tried is as follows...

I have reflective tape on both the motor shaft and the spindle nose.

I set pulley number one to the right ratio and went into the motor tuning dialog and adjusted the "Steps Per" box so that when I put "M3 S3000" in the MDI the spindle ran at 3000 rpm. (the VFD readout at this point was around 23 Hz)

I issued the M5 command to stop the spindle and physically changed the belt to low speed pulley.

I then went to set up the second pulley ratio and put in the correct ratio and went back to the MDI.

When I entered "M3 S3000" it seemed to ignore the ratio in the second pulley dialog and the VFD still read about 23Hz. I tried changing the pulley ratio to widely varying settings but it is not adjusting the commanded output to compensate for a different pulley ratio.

It seems to be completely ignoring the pulley section... I don't get it... I must be missing something...

Richard

[saabman]

Opps, did not read the whole thread to see you had done a belt drive conversion my bad.

I still suggest 60 hz.

You can compute motor RPM at 60hz from the nameplate on the motor. Then compute pulley ratio for pulley 1. Adjusts your pulses to get the the VFD to 60 hz. This should result in a spindle speed of motor base RPM x pulley ratio.

Once you have dialed in pulley 1, pulley two is a snap. Just compute the ratio and plug it in. The calibration done on pulley 1 should make pulley 2 spot on out of the box.

[saabman]

OOps, key thing you are not describing is switching pulleys on the main mach screen. The config dialog for the ratios simply sets them. You must switch between the pulleys manually.

[DarkStarMedia]

Opps, did not read the whole thread to see you had done a belt drive conversion my bad.

I still suggest 60 hz.

You can compute motor RPM at 60hz from the nameplate on the motor. Then compute pulley ratio for pulley 1. Adjusts your pulses to get the the VFD to 60 hz. This should result in a spindle speed of motor base RPM x pulley ratio.

Once you have dialed in pulley 1, pulley two is a snap. Just compute the ratio and plug it in. The calibration done on pulley 1 should make pulley 2 spot on out of the box.

See... that is the problem.... plugging in the pulley ratio has no effect... I can set the pulley ratio to 10 or .1 or 5 or anything it it does not have any effect.

Richard

EDT: when you say "adjusts your pulses" I am assuming you mean changing the "Steps Per" in the motor tuning dialog... right?