Reducing Mini-Mill Column Flex (and Column Y-Axis Alignment)

zoltan said:

Between shimming the solid column and modifying the gibs I was able to get rid of the droop. The turnbuckles are there to adjust it that fine 0.001-0.002" that I can't get rid of with shims.

If you have a mini lathe (or any lathe with a reverse) there's no to be afraid of doing LH threads.

Click to expand...

Honestly I've never tried LH threads. But I guess it would work the same way. Threading was the first thing I taught myself on my mini-lathe. But I also have yet to try internal threading. For that I normally use a tap. After learning about "fast spiral" taps, I fell in love with them and never looked back. Now I hate using a regular tap.

Nice work, Fabrickator!

Rudydubya (and all), great thread!

So, I recently purchased the Harbor Freight 4491 Seig X2 mini mill. I am going to outfit it with the mod in this thread.

I am looking for a 1/2" x 4" x 10" steel plate like what has been recommended in this thread and I am struggling to say the least here..

The closest I have found is here: http://www.ebay.com/itm/Cold-Rolled...148?pt=LH_DefaultDomain_0&hash=item27b9b1938c

and then at speedy metals I found like this: http://www.speedymetals.com/pc-2684-8244-00478-cold-rolled-steel-sheet.aspx

Both items I would have to cut down to size. I ideally would like a sheet in the exact dimensions I am looking for.

Does anybody have any ideas about where I should look for this?

Thanks in advance for any replies! Great site and thread!

Try this here: http://www.onlinemetals.com/merchant.cfm?pid=7511&step=4&showunits=inches&id=199&top_cat=197

You can specify a 10" length.

Todd

Or you can try this:

http://www.industrialmetalsales.com...1-2-x-4-x-12-1840-CF1018SteelFlat500x4x12.htm

If you email or call them they will cut it to any length you like. In fact they will sell you pretty much any dimension of the metals they carry. They are in Mount Clemens, Michigan.

I've ordered several times from either of these 2 companies and would recommend them.

If you hunt around you can find company's that will flame cut the plate from large sheets for you, they will even grind each side for you if you desire. They use black plate, so grinding will remove the scale, this is how we always ordered steel plate at work, sizes up to 100mm thick were regular orders.

These company's are usually happy to do a small job for cash, gives them some pocket money.

Paul.

Bison9, congratulations on your new mill. As for the 1/2" x 4" x 10" steel, here it is at Speedy Metals, you can buy it by the inch if you don't need a foot.
http://www.speedymetals.com/pc-481-8213-12-x-4-cold-finished-1018.aspx

Have fun,
Rudy

Bison9 said:

Rudydubya (and all), great thread!

So, I recently purchased the Harbor Freight 4491 Seig X2 mini mill. I am going to outfit it with the mod in this thread.

I am looking for a 1/2" x 4" x 10" steel plate like what has been recommended in this thread and I am struggling to say the least here..

The closest I have found is here: http://www.ebay.com/itm/Cold-Rolled...148?pt=LH_DefaultDomain_0&hash=item27b9b1938c

and then at speedy metals I found like this: http://www.speedymetals.com/pc-2684-8244-00478-cold-rolled-steel-sheet.aspx

Both items I would have to cut down to size. I ideally would like a sheet in the exact dimensions I am looking for.

Does anybody have any ideas about where I should look for this?

Thanks in advance for any replies! Great site and thread!

Click to expand...

If you can at all afford it, buy the solid column upgrade from Little Machine Shop. It works better than any column stiffening setup, and it's much, much harder to knock out a tram.

Hey all, so I got stoooooopid busy right after this post I made above right around the 4th of July and literally dropped any work whatsoever on my mini mill I just recently picked it back up again. I did the belt drive conversion on my mill the other night. I used this one:

http://www.littlemachineshop.com/products/product_view.php?ProductID=2560

As a totally side note, after this belt drive conversion, it looks like my machine in general has some pretty crazy runout. Actually though, the bolt end of the drawbar looks worse in terms of runout than the actual chuck side, but it looks like runout to me just eyeing it even without any measuring tools. Anybody see this at all ever with this?

I didn't have the drawbar cover off from before the conversion when I was running it without the Belt Drive. So I have no comparison here really from before the conversion to now after the conversion. So, anybody know what is an acceptable amount of runout on that mill spindle? I am hoping it is the chuck and not the mill that has the runout but I am a newbie at all this still (even after like 30 hours of reading online about all this stuff!). I will be actually measuring the runout on it soon anyways with a Dial Indicator so we shall see soon!

So, down to the business at hand:

Rudydubya, thanks for the link above!

Zoltan, great post too! You have me curious now also... Do you have a link to this column mod then from littlemachineshop? I will look at that site again to see if I can find it.

Thanks everybody for your responses. I am going to be scratching out these 80% lowers that have been collecting dust for a year and a half now. I hope to be taking cut number 1 sooner than later!

So, doing a simple google search, I think this is the mod?:

http://littlemachineshop.com/products/product_view.php?ProductID=4483&category=1311958022

Now, it says at the bottom of this link:

The Solid Column Conversion Kit can be used with older (X2) mini mills with the addition of one part: the Y-axis Feed Screw. Be sure to choose the correct one for you mini mill. Micro-Mark mills need the 20 TPI Y-axis Feed Screw, while mini mills from Grizzly, Harbor Freight and other suppliers need the 16 TPI Y-axis Feed Screw.

So, that Y axis feed screw is here:

http://littlemachineshop.com/4031

So Question for you all then: Do I need to get this feed screw new at this link in order to use this conversion? Or can I use the one on my current mill now with this column mod upgrade and just swap it out with this new base?

Other questions I have too then:

1.) Can I use my existing Z and Y axis gibs on this new column in the mod then?

2.) What if my X axis tram is off on this new column? Will these directions possibly include how to adjust the X and Y axis tram then if it needs it?

Sorry for the questions, I want to know if dumping $200 into this is worth it. It definitely has tweaked my interest!

Hi,i have just bought a fixed column model with belt drive and so
avoided all the expense and hassle.I dont understand why they
still make the swivel column ????

Yeah, I would have totally done this too had I known...

I found a crap to of info here also:

http://www.cnczone.com/forums/benchtop-machines/159839-lms-solid-column-conversion-kit-make-big.html

Pretty much answers all of my questions... I am assuming with the fixed base you would use shims if you were out of whack on the tram in either the X or Y axises...

Had I known, I would have gone right to the solid base model and then upgraded to the large table right away too... That is also up there on the littlemachine shop here as well:

http://littlemachineshop.com/products/product_view.php?ProductID=3677&category=-269978449

I thought I had literally researched everything on the topic of mini mills but alas, I am learning more!

After reading for the past hour or so already, I will most likely end up going with the Column sturdying mod. You then do, in fact, need to buy the new Y axis lead screw (per the link I posted above - that's if you are doing like me and fitting this all to the X2 Harbor Freight mill - model 44991). And then, I am thinking strongly about the air spring conversion and the large table because after all, go big, or go home is my motto.... All in all, I paid $500.00 for my new 44991 X2 Harbor Freight Mill back in May and I will be paying upwards of this at least if I go in to what I just listed...

I am a complete newbie though yet when it comes to all this stuff. But I don't do projects and stuff like this without quality machinery and quality knowledge of what I am doing... When I say newbie though, I have never drilled and tapped before either. I am learning this as I go as well. I have some beautiful IGaging DROs all ready to go for this mini mill and have to learn how to drill and tap and whatnot to even put these on.... I have literally been all over town trying to find scrap pieces of cast iron like the one on my mini mill to practice drilling and tapping with absolutely no luck whatsoever finding this.

All I know about machining at the moment is from the 30 hours or so I have read on the matter online. It is all theory in my brain at the moment. Past this, I know 0 so this whole experience has been very eye opening for me...

Now if I ditch the old stuff on my Harbor Freight X2 and go with these mods I discussed above, I now have the scraps I want for testing so that's a plus. Honestly, $500.00 here to basically teach myself stuff... That's basically like paying for a couple credits at some college to learn so go me I guess

***The thing that really bothers me at the moment however on my whole setup is the perceived runout I think I have on the spindle/quill of this machine that I only noticed when the drawbar cover is removed from the top of the mill head (as you remove this cover doing the belt drive conversion)...

Its like I can see the runout on the bolt side of the drawbar and not so much on the chuck side (this is good I would think!). It drives me nuts though watching that bolt and seeing like what looks like runout and not a true spin...

Can somebody address this for me? I sure hope it isn't the belt drive conversion giving me this... I guess only time will tell as I will be testing the runout soon anyways with an actual dial indicator... I just don't want to drop another $500.00 here only to find that my main issue is .1" runout at the spindle LOL :fan::rant:

I see drawbar runout too, but it has nothing to do with the chuck/spindle. That's the "business side" of the mill.

LMS High Torque

Let me see if I can answer your questions.

1. Yes, that's the kit. It's an amazing deal for the price.

2. You don't NEED the new Y leadscrew, but if you don't have it then you can't run the table all the way to the column.
2a. If you buy the large table upgrade (it's a nice mod but not necessary) then it comes with the longer Y leadscrew.

3. You reuse your gibs.

4. To tram the column you use shims. Personally I buy cheap sets of feeler gauges and then cut them up as necessary to make shims; cheap, easy, and accurate. I usually use feeler gauges side by side to get max coverage on the mating surfaces.
4a. I also upgraded the mounting bolts from the stock ones to longer socket cap bolts. The more threads you can engage in the base (without bottoming in the hole) the better.

5. Don't worry about the percieved runout from the top of the drawbar. It's not a precision piece and it's normal.

I know a lot of people will say upgrading an X2 isn't worth it. I see their point, but for me it was worth every penny. I don't have the space for a larger machine, and the work I do is usually rather small. So for me spending some money to make my mill nicer to use was definitely worth it, and my mods really do make it a much more enjoyable experience for me. You may want to check out my blog to see the other mods I've done, there are a couple in there I think you'd like: http://benchtopmachineshop.blogspot.com/

Also, if you haven't done it yet, doing the TouchDRO upgrade is by far the best bang for your buck. You essentially mate cheap iGaging digital scales to an Android tablet to create a very powerful and easy to use DRO for your mill. More info here: http://www.yuriystoys.com/

Thanks Zoltan!

I just got done ordering the Solid Column Kit from LMS. Can't wait till it gets here!

Have try a overarm
This will stop most flex in mills

Bison9 said:

Thanks Zoltan!

I just got done ordering the Solid Column Kit from LMS. Can't wait till it gets here!

Click to expand...

Has it arrived yet?

It did. And it did!

She has arrived and I pretty much converted the necessary parts of my X2 to this Solid Column.

A couple notes on this:

1.) Dang, the thing is way more sturdy than the X2 column. Its just beefier.

2.) I followed pretty much what this guy did: http://robertsprojects.blogspot.com/2013/04/mini-mill-solid-column-conversion.html to convert my X2 over to this Solid Column. All went pretty well except for the below:

3.) I put the Air Spring conversion for the X2 (https://littlemachineshop.com/products/product_view.php?ProductID=2258&category= ) on this Solid Column kit... I tried the recommendation on the 4th post at this link for where to put the air spring hole on the back of the column: http://www.homemodelenginemachinist.com/showthread.php?t=6416&page=3 DO NOT FOLLOW THIS. It is just false. This method put my hole at about the 12 inch mark on the back of the column. However, the directions right from LMS with the air spring say to put the hole 15 inches down. My first hole (done by following the link) came out not allowing the head of the mill to go down even close to where it should be at the lower limit. The 15 inch hole that LMS recommended was correct and I have full motion now with the air spring. The reason I didn't go with the LMS directions at first for this hole is because I wasn't sure if this Solid Column kit was a different dimension than the X2 column... But alas, it was.. what did one guy call it? Mindless hand wringing here... Stick with the 15 inch recommendation from LMS on this for that Air Spring hole in the column...

4.) I was out .004 on my X axis tram right away when I tested it... I have another thread going here on this: http://www.homemodelenginemachinist.com/showthread.php?t=23631. The interesting note here on this is: I first put in a .002 shim on the base to column mating surface (half the distance I was out of tram) and this left me with a .002 difference still on my next tram test. I went up to the .004 shim and I am dead on now with my tram. I did this out to the ends of the table and then took the tram so my sweep only went the length of the column (so like 4 inches between tram points) and I was spot on here as well. So, methinks the whole idea of putting in a shim half the size of the amount you are out of tram is a complete falsity to be honest... The tramming method I used was this one: http://www.machinistblog.com/how-i-tram-my-mini-mill/. But, what I did is take a 3/4" rod, put a 1/2" hole in it, and put a 1/2" x 8" cross bar in that hole to hold my dial indictor. I locked this bar down with a set screw like from the link. I tried with the cross bar the guy had in this article and the thing just moved too much in the whole system and I did not like this in the least. So, this bracket I made instead with a fixed 1/2" rod is kick arse - my Dial Indicator is fixtured basically to the end of the 1/2" rod and makes a very nice tramming bracket... There is literally 0 movement in the tramming bracket as a whole and gives the accuracy I was looking for.

5.) **A possible concern I still have is that the whole reason I went with this solid column kit is because of all the not favorable stuff I read about the column not being rigid on the X2's swivel base. I had read guys being out on their Y tram .003 - .006 right out the box with the X2 column. And hence, you see all these column firming mods going on and whatnot to remedy this... Well... The funny thing is I did a quick Y tram (Pitch) test last night on this new Solid Column setup and it looks like I am out .003 on this dawg as well out the box (and yes, I did the spindle to column tramming as well before all this and the differences there were negligible and I didn't make any adjustments). On that little X2 table that's .003 over like 2 inches on the Y side of things... So, into head scratching mode I went again... I can push my finger on that column and can move it as well like guys report with the X2 column so not real sure. I am going to throw an appropriate shim in on the Y side of things, 0 it all out, and crash into these AR15 80% lowers very, very soon. But, it still looks like there could be flex with this setup too unfortunately... Will it matter for an AR15 80% lower? Most likely not from what I have read...

That's where life stands with me on this mill at the present time!

Thanks for all the replies!

There is flex is ANY mill. Going with the solid column only reduced it, not eliminated it.

I had to tram my column in both X and Y. Also, don't forget you need to tram the mill's head first.

There is also some play in the gibs as they're configured from the factory. On my mill I marked all the gib locations using set screws turned to points, then I milled a 55* flat at each location. I then reassembled everything using cup point set screws. I threw away the locking nuts on the set screws and used green Loctite instead (it's designed for set screws). This setup eliminated almost all the play in the gibs and also allows them to slide with less friction.