[hoss2006]

Hoss, that mod to get the 3/4" inch... you just bring that boss down to even with the front web? Nice, I like easy! I've got just the monster file for the job too. LOL...

Any other travel hacks to gain a little here and there without anything too complicated for a newb?

Sure , these for travels.
http://www.hossmachine.info/X2_Travel_Increases.html

these for rigidity.
http://www.hossmachine.info/Shop_Info.html#x2%20column

When it's back together, check the tram.
http://www.hossmachine.info/Shop_Info.html#tramming
Hoss

[TroyO]

Thanks Hoss! There's sooo much info on your site, half the battle is finding it (And debating whether or not I *really* have the skill to pull it off.. LOL)

My immediate list, during the initial build...

Cleaning

More cleaning

Way smoothing

Gib polish

The 3/4" boss Y Mod (That's within my abilities)

Epoxy column fill.

Back support plate. I may upgrade that to the bolt on style later.

Full tramming out of the column to base and spindle to column.


After build:

Belt drive, using Hoss's plans. I have an 8x12 lathe and a pile of round AL stock I got at 2$ a pound.
I am considering using a 1/4" motor mount plate and some washers to fill the gap between the mounting plate and the motor where the bolts are... it just seems easier to make since I don't know how to do that recessed hole with the tools I have.
For the base plate I'm thinking I can cut the big hole just using a hole saw.. it won't be exact but "close enough".

Maybe buy a spare base (I think I read somewhere that you can order a spare base for $20 and $10 shipping...) and try some of those more advanced travel mods on one I can "wreck" and not have the machine down if I screw it up.

[TroyO]

Hmmm, that air spring upgrade seems pretty reasonably priced.

If I understand correctly, it's a better balance for the head and also extends the travel? How important is that manual use, or is it primarilly a CNC thing?

[thudson]

Hmmm, that air spring upgrade seems pretty reasonably priced.

If I understand correctly, it's a better balance for the head and also extends the travel? How important is that manual use, or is it primarilly a CNC thing?

I've been debating that. Hoss's counter weight is cheaper and probably does more to balance things. I was thinking about using a lead counter weight. Check out your local tire shop for discarded lead pieces from tire balancing. At worst I can buy big lead fishing weights for pretty cheap.

But yeah, the stock scheme is pretty weak.

I picked up some great home/limit switches from Allied Electronics for cheap. I may try to install these before re-assembling things. They are snap switches with rollers and SPDT, so they can be wired up NC or NO.

Tomy

[sansbury]

I've been debating that. Hoss's counter weight is cheaper and probably does more to balance things. I was thinking about using a lead counter weight.

I have an X2 running a Hoss-based conversion with 425oz motors, and I have not found a counterweight to be necessary. I can safely run the Z up and down at 18IPM and get basically zero backlash. The Hoss plans call for a 2:1 belt reduction on the Z so there is plenty of torque to go around.

My opinion is that you not really bother with any of the "secondary" mods until you have the basic conversion running. I say this because just getting the basics going took me about three times as long as I expected. The one exception might be the Y-axis travel mods since these require pretty much a total teardown.

[TroyO]

Thanks Bob! I knew I had seen a great tutorial on the epoxy fill somewhere, but I hadn't book marked it!

http://www.cnccookbook.com/CCMillEpoxyFill.htm

The link wasn't showing right in your post... fixed it.

From what I get on the Mini-Mill, the epoxy in this case is just for support of the rear wall of the column in the first few inches... there's no "bottom" on the column and so the tube collapses several thou if pressure is put on it. By filling it up a little past the point where the bolt goes through you can support that back wall of the column and reduce the flex at that particular point. It keeps the mounting bolt from "squishing" the column.

A full epoxy granite fill could always be done later, for dampening and such. (And probably will be.. LOL.)

I may not ever go CNC... but a 15-20% difference? It may have to go on the short list of mods instead of the "someday" list.

[knudsen]

While not requiring a teardown, I tossed the torsion bar and hardware, skipped the air lift, and used this: http://lmscnc.com/1486 The result is a good foot of Z-axis. Currently running with no assist, but bought weights to make a counterweight with a pully and cable. As I recall, the head is about 30 lbs. You can get weight lifting weights. I bought a 25lb, 5 lb and a 2 1/2 lb. I already have some 1 1/2 lb weights left from PT. 25 + 5 will get you close, might have a slight negative weight, good or bad. Actually works really well with no counter weight, and a copper shim on the gibs making it on the stiff side.

On the epoxy, search for potting compound. It's made to settle in and fill voids. Very dense. Might have to seal the cavity with silicone or regular epoxy first. I would mix some lead shot with it. Again, I have not done this yet. Not had mine apart. It's only 5 years old... all in due time

[thudson]

I say this because just getting the basics going took me about three times as long as I expected.

This is what I am finding out. I am just about finished with tear down and cleaning, but my gibs and some of the dovetail surfaces don't look so good.

I spent most today polishing the z-axis gib. It looked warped and was only polishing up on the ends. Some of the ways had been painted. The surface finish on important areas wouldn't pass muster for non-critical areas where I have worked.

After all my work I reassembled the z-axis and the movement was noticeably improved.

I still don't think I did that good of job on the dovetails, now that my gibs are parallel and mirror finish I may try lapping the dovetails.

I'm beginning to realize what you're really buying is all the raw materials to make a mill. It's up to you to actually make it one.

BW, thanks for that link, I may go ahead and do that for dampening, since I already have epoxy on hand. While I am at it I might do the base as well.

I am aware of the potential allergic reactions. I know some people that had to give up boat building because of the reaction. You don't ever want the stuff wet or dry touching your skin (and if you're sanding it, you need a mask and good dust collection). After my initial fears I became an epoxy nut. It is the solution to *everything* .

TroyO, plan on doubling your estimates for time spent getting the machine ready. I'm pretty sure I won't be cutting chips for another two or three weeks. Of course I tend to go OCD on tool accuracy, I even have a DRO on my table saw.

Tearing it down completely has been a good exercise. Every step shows me another potential area for adjustment.

[degreaser]

I picked up some great home/limit switches from Allied Electronics for cheap. I may try to install these before re-assembling things. They are snap switches with rollers and SPDT, so they can be wired up NC or NO.

Tomy

Take a look at this limit switch installation. I plan to use something similar in my rebuild. Best I've seen...

http://www.cnczone.com/forums/showpo...7&postcount=45

[thudson]

Take a look at this limit switch installation. I plan to use something similar in my rebuild. Best I've seen...

http://www.cnczone.com/forums/showpo...7&postcount=45

That's sweet, good idea.

[Bluedog]

Definately do not overlook the last part of Hoss's tramming section with this link:

http://homemodelenginemachinist.com/...p?topic=6007.0

This made a world of difference in the accuracy of my mill.

[thudson]

Definately do not overlook the last part of Hoss's tramming section with this link:

http://homemodelenginemachinist.com/...p?topic=6007.0

This made a world of difference in the accuracy of my mill.

Wow. I am a constant reader of Hoss's site. I haven't seen this though. Thanks!

[TroyO]

LOL, yep I'm sure it will take a while. I'm somewhat less OCD about the tool accuracy.... but maybe not by much. I dropped $200 on a Incra cross cut sled so I could set angles to within .01 degree.. LOL...

A tip, if I may... start with a file on the jibs and dovetails. On my 8x12 lathe I started with sandpaper and after an hour gave up and jumped to a file to get them close. Actually, I think I even used the belt sander, then the file, then sandpaper. Glue the gibs down with hot melt and you can file/grind on them better.

I was also considering sacrificing a diamond hone and cutting one side to the compliment of the 55 degree dovetails. Maybe it would go faster?

[thudson]

I dropped $200 on a Incra cross cut sled so I could set angles to within .01 degree.. LOL...

Yeah I love Incra stuff, I have the router fence, made quite a few 'double-double-through-double-dovetails' LOL

A tip, if I may... start with a file on the jibs and dovetails. On my 8x12 lathe I started with sandpaper and after an hour gave up and jumped to a file to get them close. Actually, I think I even used the belt sander, then the file, then sandpaper. Glue the gibs down with hot melt and you can file/grind on them better.

Yeah, my mistake. I thought I was dealing with some precision gibs and the thought of taking a file to them horrified me. Honestly I could have started with a course grinder.