New mill is on the way

Hi Peter,
Most people put the 3rd axis on the knee and use a cheap scale on the quill.

I have been watching this thread, nice mill and that DRO will make a hue difference.

Dave

Hi Peter,
Dave is correct. I have my 3rd axis scale on the knee and the small modified caliper reader on the spindle. I have 18 inches of travel on the knee so it was more useful to have the 3rd one mounted there. The kit will give you any sized scales you want.
The Y axis was a little more difficult to install than the X axis, not so much for the scale but attaching the brackets for the reader head. They supply you a variety of angle brackets with the kit but one issue I had with them is they have the full thickness of the bracket (.375) where there are existing holes and slots, the other areas are thinned down to half that thickness so if you have to move screws around you have to get a little inventive for mounting. The reader head has a recommended way of mounting which is on the bottom with 4-4mm screws. On the side of the reader head are 2-5mm tapped holes that can also be used. They show it being mounted by the latter holes in the instructions but tell you to use the 4mm holes. ???
I had to make an adjustable base plate to mount the brackets as the surface for mounting was irregular. I made it out of a piece of aluminum with 2 mounting screws and 4 set screws to get it plumbed before I started mounting the remaining brackets. Here are a couple of shots of the finished setup.
gbritnell

As I said the 3rd scale was mounted for the knee. This involved making a spacer block to mount the scale as the machine is cast with a tapered column. I mounted the base for the scale at the bottom and then plumbed it to get a dimension for the aluminum block at the top. I cut the block a little thinner than needed as I could jack it out with the set screws to get it plumbed. Once this was fairly plumb I mounted the scale and started indicating it. With that done I started modifying the angle plates to get the reader head in place. With this setup I had to mount the first plate and then add a piece of aluminum plate to get high enough to mount the second plate. This reader head also had to be mounted with the 5mm threaded holes in the side.
All in all it came out good and is working very well. The readout box has a myriad of functions, absolute/incremental, bolt hole circle, positional memories, bolt holes at an angle, etc. etc.
It does have one feature that I have been using quite a bit. It's a center reading. You touch off both sides of your job and then hit the 1/2 button and then the desired axis and it gives you -0- for that axis center. It saves some calculator math.
The hardest thing to get used to is the tenths digit on the reader. I purchased the 2 tenths scales and when you're moving the axis you have to creep up on the reading.
gbritnell

I use the 1/2 feature more than any other.

A use I found for the abs/inc was to set it to 0,0 at the vise fixed jaw + vise stop. So as long as I leave the vise and stop in place, I have a zero point without needing to measure. The inc setting I use for everything else.

Great to see you got the mill and it all worked out OK.

I know I am really enjoying working with mine, such a difference to the mini mill. I have been looking to fit a DRO so its really great to see your pictures of that too. I like the way you sorted out the Y axis tram too, simple and effective. I had been thinking about doing something similar as mine is a couple of thou out over 6".

Do you mind if I ask what length scales you went for in the end?

gbritnell said:

Well the mill is in place.
When my buddy and I took it out of the crate we moved what we could down to the basement. The 2 remaining pieces, the base and the column would need an appliance truck to get them down the stairs.
Saturday my sons came over and we started out by moving the aforementioned heavy pieces down to the shop. I had already measured everything and put some tape on the floor as a guide to locating the base. Everything went great. We got the base in place, mounted the column with the bolts lightly snugged until the knee went on. This way I could drop the knee to the bottom to get the column located back to it's original position. The parts drawing showed 2 dowel pins along with the 6 bolts but there were no dowels. The column had 2 tapped holes which corresponded to 2 reamed holes in the base. I used a couple of metric allen screws to get everything close.
The knee was next. I had removed the gib plate to facilitate dismantling so with a coat of way oil it was re-inserted and adjusted.
Next came the saddle followed by the table. The gibs were inserted and adjusted.
Man that thing moves smoothly!
The ram and base were located on top of the column and bolted down.
Now came the awkward piece, the spindle casting with belt housing and wiring. We put some 2x4 pieces of lumber on the table so that we could carry it in and set it on the wood. Once sitting there the knee was cranked up and the head was located onto the ram and bolted. The final big piece was the motor. It was located on the belt housing, the belt was put back on and snugged up.
From start to finish we had about 3 hours of assembly.
The boys were dismissed from their labors and I finished cleaning up the remaining spots of cosmolene, adjusting handles, gibs and what have you.
The next day I ran over to the local home store and picked up the required electrical items. An hour of stripping wires and assembling plugs and it was time for the test. E-stop button turned out, main power on and turn up the variable speed knob. Everything worked just as it was supposed to.
I trammed the head, x axis was dialed in to -0- in 8 inches but the y axis was out -.001 in the rear and +.0017 in the front. (in an 8 inch sweep) I loosened the turret and rotated it back and forth just to make sure there was nothing under it. I reindicated and got the same results. I wish it was closer out of the box but I knew how to fix it. I loosened the turret again, put a piece of wood on the table, cranked the knee up until it just lifted the turret/ram and inserted a couple of pieces of .002 shim on either side of the front fixing bolt. I lowered the knee, tightened the turret bolts and reindicated. I now have -0- in x, -0- in the back and +.0006 in the front. I can live with that.
All that's left to do is mount the vise and make some trial cuts.
I'll keep you notified on the progress.
Here's a couple of pictures. One of the machine and one with it's so far happy owner.
gbritnell

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Just curious after three years of use how is the mill holding up? Also, how tall are you? I'm six foot five and I am trying to see how the height will work for me. Thanks

After 3 years the mill is doing great. I'm 5' 11" so for you there would be a lot of bending but even with something larger like a Bridgeport or Bridgeport clone you would still be bending.
Here are a couple of things that are bothersome about the new mill.
1. With the height of the machine the speed control box is mounted in such a way that when working from certain angles it's just plain in the way. The only cure would be to make a bracket and move it up about 8 inches.
2. The same goes for the fine down feed handwheel but there's no moving it.
3. It has a one step oiling system, pull the handle and all the axis get oiled. The problem is the oiling points with the shortest lines get an overabundance of oil while the farthest (knee points) get only a little. I guess the simplest fix would be to pull the lines and put some type of restrictor in place. Usually what I do is pull the handle until the X axis weeps oil and then oil the knee by hand. It's not that the knee is continually going up and down like the other 2 axis so as long as it has a good coat of oil everything is fine.
After 3 years when I periodically check the tram it's still as good as when I first set it up. That's not meaning that it doesn't move or when I choose to move it it just means that it can be brought back to the original numbers. X- .000, x+ .000, Y- -.0005, Y+ +.001. That's using an 12 inch indicator arc
4. I fought with the knee trying to resolve the accuracy difference when moving it up and down. Let me explain. With the head trammed I set up a known true angle plate on the table (8"). I then set an indicator in the spindle and against the angle plate. With the gibs adjusted to what I thought were proper I would get a difference of .005 when going from up to down. Hmmm! So naturally I tightened the gibs up. This only amplified the problem Hmmm! And by tightening the gibs it made the knee very jerky (sticky) so I stopped to sort out what was going on. Even if the knee was sticky it should have resolved the dimensional error but it didn't so I started going the other way (loosening the gibs). Actually by loosening them I got the vertical error down to about .0015 and the stiction was gone but I felt the gibs were too loose. With this adjustment I have no machining problems and the only thing I do is make sure that when I make my initial setups I have the knee leadscrew loaded (cranked up) and then if I move it up or down I do the same thing, crank it down to where I want to go then turn the handle to take the backlash out, lock the knee and I'm good to go. It will repeat within .0005 by doing it this way.
That's about it. I love the variable speed control and I really like the reverse for tapping.
If a person has the floor space and ability to move a larger machine I would recommend a machine like a Bridgeport only for the fact that there are so many of them out there (depending where you live) and that a nice one can be had for about the same money as I paid for my machine.
gbritnell

The system for oiling uses restrictors, either at the manifold or at the finial end, and they are each a different quantity. Check the numbers on them and maybe swap some around, its not the length of the lines, its the restrictor installed.

gbritnell said:

After 3 years... I really like the reverse for tapping.
If a person has the floor space and ability to move a larger machine I would recommend a machine like a Bridgeport only for the fact that there are so many of them out there (depending where you live) and that a nice one can be had for about the same money as I paid for my machine.
gbritnell

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I'm about to pull the trigger on this machine, just want to verify when power tapping, you can just throw the reverse switch to back out the tap WITHOUT NEEDING TO SLOW DOWN THE SPINDLE? This of course assumes tapping at a reasonably slow speed to begin with.