thoughts after six months

[altaic]

I've had my IH manual mill for about six months now, so I figured I'd write about my experience thus far. Firstly and foremost, this was my first mill and I have no idea how I got along without one before. It's just so useful!

So, the good:

It's a pretty huge machine as far as home shop machines go. It's work envelope is large enough to handle basically whatever ideas I might conjure up. Furthermore it's pretty damn rigid. I haven't had to re-tram the thing since I got it; throughout all of my mistakes and abuse the thing has never gone out of tram (according to my ez-tram and 0.0001" mititutoyo digital indicator). It makes me feel a little better about pushing the machine as hard as I do.

Speaking of, my x-axis power feed just started acting up and it sounds like it's on it's last coil; it rapids at like 5 ipm now. What is this doing in the "good" section, you ask? Because Gene@IH told me to just pack it up and ship it back to them for warrantee replacement. It's all about the service.

Now, room for improvement:

The aforementioned rigidity (and any sort of precision) is highly dependent on tightening the crap out of every gib, gib lock, quill lock, you name it, but obviously you can't tighten everything-- otherwise you wouldn't be able to move the piece to be machined. So you tighten almost everything and what's left is backlash, and plenty of it. To name a few places: each axis' leadscrew/nut (0.01"), x-axis leadscrew bearing (0.005"), quill (0.01"), quill shaft key (0.01"), quill microfeed shaft key (0.005"), quill microfeed worm (0.01"). I'm sure the column z-axis has backlash, too, but I always remeasure after moving and locking the head, so it's of no consequence to me.

I first fixed the quill shaft key and microfeed shaft key backlash, since it was a simple matter of wrapping the shafts/keys with 0.001" shim stock. The leadscrew bearing I also fixed with a shim, because I was worried about wear (in retrospect I don't think it mattered much, but it was nice to have less backlash, for sure). I'm currently figuring out what to do about the quill backlash, since it appears that I'd have to buy some new gears. That might also help with spindle runout when the quill's unlocked (pretty nasty compared to the spot-on runout when it's locked). I've been doing a lot of boring lately and the quill has been getting on my nerves.

Anyhow, I also took the quill microfeed entirely apart because there was a sort of notchy sticky feel, and I was thinking I'd have to replace the bearings or something. Well, what I found was it wasn't bad bearings, it was that blue paint! It appears that painting is the last step of manufacture, because they'd painted over the bearings, grease and all. This was sort of a relief, since I just had to soak the bearings in paint thinner and repack them, but I admit it was a little shocking-- bearings are the sort of things that should under no circumstances encounter paint.

So, the next thing that caught my attention was the fact that the gib locks cause the table to move as much as 0.02" in the x-axis and sometimes up to 0.005" in the y-axis. I took the gibs out to inspect and decided to get new ones, although I haven't yet. I suspect that'll happen just about when I replace the leadscrews with ballscrews (soon).

That reminds me, the gib lock set screws came with a nut on them, I guess to keep them from falling out; however, when the set screws are tightened to lock the gibs, the nut doesn't have enough threads to stay on. The easy fix was to replace those wimpy set screws with hex bolts of the proper length.

And lets see, that's pretty much it, except for little niceties:

I've added a few bits and pieces on the mill column like a hook to have a 3/4"&5/8" box wrench handy, a Uni-max Coolubricator microdrop lube gadget (works nicely and I'm still on the sample bottle they send with the unit; it does so much with so little). I've also welded up a vice table (mounts on the mill stand) which sits behind the mill table to the right of the column. I raised the mill a bit with some nice vibration isolating hockey pucks and then stuck a tool chest (holds all of my mill tooling) to the left of the mill so the mill table passes over it. I also just recently replaced all the cheesy, slippery plastic hand wheels with polished cast iron ones made by Jergins (was on sale at MSC for $7 for a 4" one, and $15 for 6" ones). They are actually really nice looking, with the added benefit that I can grip them without a perpendicular handle. This is particularly nice because my y-axis handwheel no longer has a handle on it to jab me in the balls every freaking five seconds.

Well there you have it. This machine has been great, despite my (constructive) criticism above. I've milled (and turned!) all sorts of materials with it, from exotic wood to tough stainless, and it has fulfilled it's duty with valor.

[ruawake]

Thanks, that was very helpful for a newbie like myself. I am impressed with this machine. I just wonder why geared servo motors, 0 backlash just not possible......

Thanks
ruawake

[sharpshooter90]

Originally Posted by altaic I've had my IH manual mill for about six months now, so I figured I'd write about my experience thus far. Now, room for improvement: The aforementioned rigidity (and any sort of precision) is highly dependent on tightening the crap out of every gib, gib lock, quill lock, you name it, but obviously you can't tighten everything-- otherwise you wouldn't be able to move the piece to be machined. So you tighten almost everything and what's left is backlash, and plenty of it. To name a few places: each axis' leadscrew/nut (0.01"), x-axis leadscrew bearing (0.005"), quill (0.01"), quill shaft key (0.01"), quill microfeed shaft key (0.005"), quill microfeed worm (0.01"). I'm sure the column z-axis has backlash, too, but I always remeasure after moving and locking the head, so it's of no consequence to me. I first fixed the quill shaft key and microfeed shaft key backlash, since it was a simple matter of wrapping the shafts/keys with 0.001" shim stock. The leadscrew bearing I also fixed with a shim, because I was worried about wear (in retrospect I don't think it mattered much, but it was nice to have less backlash, for sure). I'm currently figuring out what to do about the quill backlash, since it appears that I'd have to buy some new gears. That might also help with spindle runout when the quill's unlocked (pretty nasty compared to the spot-on runout when it's locked). I've been doing a lot of boring lately and the quill has been getting on my nerves. Anyhow, I also took the quill microfeed entirely apart because there was a sort of notchy sticky feel, and I was thinking I'd have to replace the bearings or something. Well, what I found was it wasn't bad bearings, it was that blue paint! It appears that painting is the last step of manufacture, because they'd painted over the bearings, grease and all. This was sort of a relief, since I just had to soak the bearings in paint thinner and repack them, but I admit it was a little shocking-- bearings are the sort of things that should under no circumstances encounter paint. So, the next thing that caught my attention was the fact that the gib locks cause the table to move as much as 0.02" in the x-axis and sometimes up to 0.005" in the y-axis. I took the gibs out to inspect and decided to get new ones, although I haven't yet. I suspect that'll happen just about when I replace the leadscrews with ballscrews (soon). That reminds me, the gib lock set screws came with a nut on them, I guess to keep them from falling out; however, when the set screws are tightened to lock the gibs, the nut doesn't have enough threads to stay on. The easy fix was to replace those wimpy set screws with hex bolts of the proper length. And lets see, that's pretty much it

That sounds pretty much like the typical off the shelf Chinese machine. I thought that IH claim to fame was that they brought these machines in from China and then completely re-worked them here.

[EvanVH]

Originally Posted by sharpshooter90 That sounds pretty much like the typical off the shelf Chinese machine. I thought that IH claim to fame was that they brought these machines in from China and then completely re-worked them here.

That is a manual machine. (?) I think you are talking about the cnc version.


Altic

Those gibs can't go bad in six months. If the gib still wedges into the saddle then it is not bad.

If you approach in the same direction that you approached when you set zero then backlash is not a problem.



Evan

[altaic]

Originally Posted by EvanVH Those gibs can't go bad in six months. If the gib still wedges into the saddle then it is not bad. If you approach in the same direction that you approached when you set zero then backlash is not a problem.

Hi Evan, I actually have a dro, so it's not a problem insofar as losing calibration/zero; it's more of a nuisance when making small adjustments or when pocket milling. I'm not sure what's up with the gibs; they looked alright to my eye (I didn't attempt to measure the flatness), but they definitely cause the table to move when I tighten the locking screws.

[altaic]

I'm sorry, I just realized something: when I said gib locking screws, I meant slide locking screws. Gib adjustment isn't a problem, and the gibs aren't worn away or anything. It's when I tighten the slide locks that the table kicks over a couple hundredths.

[madman]

Could be more trouble when running cnc as it would move more and wear so quickly?? Is this a machine that requires daily gib adjustment?? Unusual? But it sounds like a nice unit with a good work envelope. Point being if you have to rweak it constantly to keep accuracy what good is it really? Not Much in my opinion?

[Cruiser]

If your getting .02" movement when cinching the side snubs then you are not running the gibs tight enough. If you have steel balls or use the end of the bolt or set screw in the side snubs then you are also deforming your gibs. There may be plastic or nylon plugs in the snubs, then you won't deform the gib but you will destroy the plugs if overtightened.
In the (any) manual machine there is going to be slop in the screw and nut assy as well the drive end at crank. It is very difficult if not impossible to get rid of this slop.
I have a cnc old 10" model and took out the side snubs for all the gibs. Won't use them, period ! If you have the newer machine with the ground slides and gibs then you should be able to adj the gibs to very near zero play easily and experience no grabbing.
I don't know what your experience level is with machinery but I'd suspect that your a virtual rookie. The key to running these machines is knowing how to properly setup and adjust it from one end to the other.
If your using an oil with a low shear then you will have a much higher resistance to movements than if you used a quality machine oil which has a super strong film or surface tension, which is quite sticky and will not get squeezed out of the run area and allow easier moves.
Six months is not a reasonable time frame for allowing the machine to be run in either, As the slide ways all mate together and show signs of wear It will be able to be tightened up some more and yet move easier, Assuming of course proper oil is used !
A trick to getting slippery slides and gibs is to take some Moly eng assy lube, which has a very high content of molybdenum disulphide, and rub it against all the slides till you can see the moly turning the iron dark. You don't want to leave the grease behind, you want to permeate the surface with the moly, then oil the slide ways and run the machine to the other extent of travel and do that part of machine. you can apply it to any iron to iron surface and it will decrease the friction and allow tighter running. I washed my iron with a strong solvent before rubbing in on my machine and it did make a huge difference, just don't leave the grease behind to attract and hold chips and fines.

[Runner4404spd]

also one thing i noticed on my machine is that the gibbs were too narrow to fit and wedge properly. so i added a .005 shim on one axis and a .010 shim on the other axis. this allowed the gibb to fit tighter and then the gibb adjustment screw didn't bottom on it thread. so now i could actually run the gibbs tighter and not have to use the axis locking screws as adjusting points.

[Cruiser]

I forgot all about the shimming of the gibs on the older lapped in ways. I used .009" on mine to get them where they needed to be. Good point to bring up !
Of course this is not at all needed on the newer ground machines. Or so I presume.

[Runner4404spd]

it may or may not be needed. but ultimately it doesn't hurt to put it in, to make sure you can properly adjust the gibbs. if your adjusting the gibbs with the lock screws than thats not right no matter what and chances are good you need a shim.

[altaic]

Originally Posted by Cruiser If your getting .02" movement when cinching the side snubs then you are not running the gibs tight enough. If you have steel balls or use the end of the bolt or set screw in the side snubs then you are also deforming your gibs. There may be plastic or nylon plugs in the snubs, then you won't deform the gib but you will destroy the plugs if overtightened.

Interesting. I was considering using soft tip set screws, but I thought it probably didn't matter since the screws that IH packages with the machine are standard cup tip. However, I replaced the screws that came with the machine with oval tips. Could that deformation while tightening the side snubs cause the table to move slightly?

I'm running the gibs pretty tight, but I'm worried about my x-axis powerfeed. Any tighter, and the powerfeed audibly changes-- I've already had one powerfeed die on me, which Gene@IH kindly and promptly replaced.

Originally Posted by Cruiser In the (any) manual machine there is going to be slop in the screw and nut assy as well the drive end at crank. It is very difficult if not impossible to get rid of this slop.

Oh yes, but it sure feels nicer when most of the slop is eliminated. The one place slop is really a problem for me is in the quill, which is still a real pain. This being a CNC forum, I realize that many people here lock the quill and never unlock it, just using the z-axis. Unfortunately that doesn't work so well for my manual machine :/

Originally Posted by Cruiser A trick to getting slippery slides and gibs is to take some Moly eng assy lube, which has a very high content of molybdenum disulphide, and rub it against all the slides till you can see the moly turning the iron dark. You don't want to leave the grease behind, you want to permeate the surface with the moly, then oil the slide ways and run the machine to the other extent of travel and do that part of machine. you can apply it to any iron to iron surface and it will decrease the friction and allow tighter running. I washed my iron with a strong solvent before rubbing in on my machine and it did make a huge difference, just don't leave the grease behind to attract and hold chips and fines.

Nice trick! What kind of solvent did you use? Acetone, or perhaps brake cleaner? I've used brake cleaner on a towel immediately followed by an oiled towel (otherwise rust forms lickidy-split) for some engine parts.

Originally Posted by Runner4404spd also one thing i noticed on my machine is that the gibbs were too narrow to fit and wedge properly. so i added a .005 shim on one axis and a .010 shim on the other axis. this allowed the gibb to fit tighter and then the gibb adjustment screw didn't bottom on it thread. so now i could actually run the gibbs tighter and not have to use the axis locking screws as adjusting points.

I'm having a bit of trouble visualizing where you shimmed. Was it on the length of the gib?