[1HobbyMachinist]

Hi everyone, I'm Mike. I am 34 years old. I got into machining a few years ago when I bought an X2 from HF. I bought it when I realized my HD drill press just wasn't accurate enough for the project I was working on. Since then I have made lots of chips and done a bit of upgrading to the mill. I converted to belt drive, lapped the ways to DEATH, (GOD I wish I never read about that CRAP!!!) and I filled the base and column with steel bits and JB Weld (I'd use epoxy-granite if I could do it over, and I will when it's time to work on the 45)

My hobby shifted to rifle building, and I moved to a larger mill, an Enco RF45. With this new work envelope, I decided to do some of the upgrades to my X2 that I had read about. I wanted to stiffen the column mount, and CNC the little mill. I bought roller taper bearings for the spindle, hatched a hair-brained idea for running an oil bath over the spindle bearings and started working on my column. Now I think I'll look into those nifty angular contact bearings and the Kluber (sp?) grease.

I now realize my idea for stiffening the column was flawed. Here is what I did: Mill the back of the base square, mill the column mounting point slightly angled forward, attach a thick piece of steel to the back of the column and allow the big bolt to go through it plus additional supporting bolts. Then the big idea was to use a carefully machined spacer between the base and that piece of steel to pull the column back into alignment. Then the column would be under tension (or something) and should be more rigid for it. But I never could get it to tram out right, and frankly I gave up for several years. My 45 ran good, trammed out decently and made lots of chips.

My problem was simple, I was not a machinist. I did not know what precision was or how to attain it. I still am not, and most probably do not, but now I have a clue. A few months ago, by accident, I discovered scraping. The more I read about it, the more the wheels started turning in my head. It couldn't have come at a better time for me either, because I had grown bored of building rifles, and I needed a new hobby.

So I bought a lot of stuff;
24 x 36 AA granite surface plate
8 x 12 granite 4 face right angle - thingy
18" PMC Squaremaster
Anderson Bros tube type scraper and carbide blades
Accu-Finish series one to sharpen the damn carbide blades! :drowning: It is a nice tool though...
Plus I milled up a nifty little fixture that will (somewhat) accurately cut from a 1" to a 6" radius on the blades.
Book and DVD from Micheal Morgan plus his straight edge casting
Machine Tool Reconditioning by Connelly
Several different indicators, but the only one I trust a little is a digital .0001 x .5 I picked up on Ebay, and I only trust it over short distances...
A pretty nice square gauge block set to the tenth (Of course it's more accurate than that, but tenths is as deep a water I intend to swim in )
A good bit of class 40 cast iron for making gibs and straight edges and such
I already had a heat treating kiln, so stress relieving the castings is no problem

So now I'm working on the old X2. I figure it's a good little project to learn on, and if I screw it up - well I wasn't using it anyway...
Now that I'm looking at the X2 with a bit of knowledge, WOW! It's a wonder I ever cut anything with this POS. Seriously, this thing has a lot of issues. Now some of this might have been caused by my exuberant application of lapping compound before I knew better, but not all of it.

Based on what I read, I needed a datum point to base all my other measurements on. I also needed to practice scraping, so I decided to scrape the bottom of the base casting. The reason was simply because I can put it on my surface plate, and so I can just pile things on top of that and get accurate, repeatable measurements.

After a quick rough scraping and debur, I put the base on the surface plate, and it rocked! :facepalm: Once I realized scraping isn't too hard, and my bearing surface started showing up, I decided to check the height of the ways. I figured it would be easier to cut the bottom down than the ways.
Turns out they were off 3 thou left to right. Now this by itself probably doesn't matter, I doubt Seig uses the base of the machine as a datum point (I don't know how else they could do it, but whatever) The problem is that each way was tilted. One was off 1 thou front to back, the other was off 3 thou but in the other direction. It was twisted I guess. To top it off, one of the ways was not completely machined. There was a ridge approx 10 thou x 10 thou at the most inside point of the bottom left way. As I did the saddle, I noticed the impression left by this ridge (my lapping probably helped to cut that depression) So far I have only measured the tops and bottoms of the ways, I'm still working on tooling to do the dovetails properly, so who knows what I'll find there.

As far as the saddle, it was both twisted and warped. It rocked on the surface plate too. I don't remember how far out it was because it was the first one I did after the bottom of the base, and I just sort of jumped into it.

Now the table was just ridiculous. It was a twisted banana. The top was concave by 5 thou! I have the top pretty flat now, but I'm waiting on some new tooling to make the angled straight edge I'll need to do the dovetail.

That's as far as I've gotten. I have most of the flat horizontal surfaces flat to + or - 3 tenths. Those last couple of tenths are a pain! I think I'll leave the column and head alone until I get the base, saddle and table done so I don't get overwhelmed. It is an exhausting amount of work, but it is fun too. I like the idea that I can check my tooling to see if it is accurate (at least to a tenth anyway) instead of just relying on a name brand and hoping the machinist didn't sneeze

Anyway, thanks for reading all that (or at least for skimming down to the bottom) I fully intend to CNC this little mill if for no other reason than to gain experience for when it's time to work on the 45. I am sure I'll have lots of questions, so thanks in advance for the help.

In fact, here is my first question:

I am a little irritated by the gib system on the X2. I am playing with the idea of machining a new saddle that is a little wider on both sides to allow me to install a tapered gib. What are your thoughts on this idea? What kind of material should I use? Right now I'm looking at class 40 cast iron or 4140 which I can heat treat. I'm not set in stone to do this, but after all the effort I'm putting into this little mill, I think it would be a shame to use these "open air" gibs :boxing:

Mike

[LUCKY13]

I really like your right up, and its full of info that so many of use go through on the learning curves with this hobby ( atleast the ones that really dig into the subject).



Your aproach to your little X2 is good IMO. There is a lot to getting any machine to be accurate. and the truth is there is probably not a Asian hobby class desktop machine out there that are really accurate.



YOu have to start from the base so your going in the right dirrection. After all it what all measurements respond to. On your saddle I would go with the class40 iron, the other will work find but the iron willl be easier to work, plus it should give more vibration dampening ( cast iron controlling vibrations is mainly why machines are built from it). Today with better tech in weldments and such we do see many machine not made of iron but they are normally very high tech and expeincive. Then there is the epoxy granite route.


These benchtop machines all go through a seasoning of the casting. This can cause the warping/bending of all the parts even if they where straight to begin with. So heat treating/stress relieving even more will be good. Heck if you dare, or can afford, cyro treating could be a extreeme step to take ( the dovetails & gibs would wear much better then). ABit overkill, but thats what taking it to the next level is about. And by all means go with a tappered gib setup if you go this far, and allow anough room to make the gibs thick enough to hold up and not bend.

Many of the machines get the bases warped/bend from the mounting used when bolted to a bench. Once you get your base fixed make sure you dont kill it again with improper mounting(I am not saying you killed it the first time). Also any improvments you can do to stiffen the castings should be done before cutting & scraping ( epoxy fills, cross supports, added plates and such).


You will learn a lot on this project. And if you get it right you will see just how much a good bearing surface ( scraped ways) really adds to the performance and accuracy of a machine. I giggle when I see machines sold with what they call frosting to add oil retention, and the buyer goes on about how the machine is factory scraped (not). Both are important, but a bunch of random half moons on a way is not scraping. A properly scraped way and saddle will move like it is riding on fluid. It will also have much more stability and accuracy if they are straight. So the performance and speed when CNCed will be much better. Once you master the X2, the RF-45's are just begging for someone to make them into a real machine. My RF-45 is 12 years old and it set for 10 years before even being used. Right from the get go it has problems much like your X2 just from the casting settling/seasoning, and not being setup properly on a bench (it was just stored)

Years ago when I was racing we use to take old engines blocks and throw them out in the weather for a few years. The blocks would change and season at whcih time we would remachine them. They always made for a much stronger, more stable engine after doing such. Its just the nature of cast iron, you either do it to the part through treatments and such, or you let it happen naturally. EIther way the part will always hold its structure much better.


I will be looking forward to seeing how you come on this project, should be interesting.


Jess

[TroyO]

Heh, what a familiar story....

I have the scraping vid, and have ordered the recent series of articles in The Home Shop Machinist which inspired me to start down the scraping path myself. The first project of which will be....... you guessed it. the X2, LOL.

I just bought a base casting, and I have ordered a saddle and table. I intend to use my existing mill to machine the new parts and hand scrape to perfect those first, and when everything moves and fits to my satisfaction it will get ballscrews and hopefully become my X-Y base for the CNC coversion.

Carbide scrapers have been made, shaped and lapped. Huge block of cast iron (12x3x2) has been rough milled on one side for the scraping process to start.

I have the newer base casting with the open back... it will get a redesign to extend the Y and get rid of the tilting column entirely.

Some of it will need to be able to be machined which precludes including gravel/sand/rocks in it, but some parts of it may get a JBGranite fill.

Do-Over I may have ordered the extended Y base from LMS for $66 (The standard base from HF was only $20) I would still do the extended travel way extension on it... but the end travel would be about an inch more... 7.5 instead of 6.5 Ohh well, hindsight 20/20.

LittleMachineShop.com - Base

I will be following your thread with much interest since it sounds like I will be just a littlle behind, LOL!

[Johann ohnesorg]

am a little irritated by the gib system on the X2. I am playing with the idea of machining a new saddle that is a little wider on both sides to allow me to install a tapered gib. What are your thoughts on this idea? What kind of material should I use? Right now I'm looking at class 40 cast iron or 4140 which I can heat treat. I'm not set in stone to do this, but after all the effort I'm putting into this little mill, I think it would be a shame to use these "open air" gibs

Hope you haven´t started jet on the ways. Blue them up, see where they bear. It´s a joke. The Sieg ways have three angles, not one. The gib itself flexes wherever it wants so even with these bad ways, these machines do surprisingly accurate work. Get a 60° milling cutter, remill both saddle and table plus the base to 60° dovetail angle instead of the 55° you have now. This gives you 1/8" more gib thickness due to milled away material and a straight and parallel way to start scraping from if you do it in one setup on your RF45. Be careful not to bend the castings with holddowns and excessive force, it´s done far easier than one thinks it could happen. After milling them parallel and deepening the cutouts in the dovetails Vee scraping them to 10 bearing points per square inch is a breeze. Don´t overdo it, more won´t help since the soft cast iron will always wear, it´s a bad material due to bad processing in China and lots of small gas inclusions. Just compare it to a piece of normal grade american made cast iron and you´ll see what I mean. New gibs should be made of gun metal, brass or cast iron and scraped to fit. Cast iron is the material of choice here, use brass or gunmetal if on hand anyhow I´ve never seen a hardened gib so far but heared a lot of people with no clue talk that this would be the best. :bs: Stay away from it...
A last thought: Whenever you mill a way parallel throw in a normal endmill afterwards and mill a strip on the castings side, this makes setup for a second way around far easier and helps with measuring later on. Or it could be a mounting surfaxce for a glass scale or a digital calipher for your DRO. A straight and parallel mounting surface surely helps a lot. There´s one thread here about reworking a X2, without scraping but with stretched travel and a lot of milling, especially in Y. Read it before you start.

Cheers,
Johann

Ps.: Seasoning a cast iron engine block after it was already used is worthless, it travels in a far wider temperature regime due to use than it will ever see in a shed or out in the open. That one only works on new castings. It is better to heat up a casting to elevated temperatures, hold it for a few hours and let it cool with a specified drop of temperature per time to get rid of residual stress. There´s a fairly good paper out there on this topic by the navy research institute from the 1940ies.

[1HobbyMachinist]

Thanks for the very thoughtful replies guys. I'm sorry I haven't replied in kind, but frankly, you guys are just too articulate for me!

I've tried a couple times already to write some well thought out replies, but I keep overthinking them and deleting. Suffice it to say that I appreciate the help, and I am definitely using the info!!

I haven't gotten much done lately, been feeling a little sick plus I was a little confused as what I should do next. Johann's advice on remilling the dovetails helped a lot. I still am going to make a new saddle, as there are more problems with it than I have mentioned, and cutting the dovetails will make one even worse, but now that I know I am going to cut the dovetails I was able to move to the next step.
Today I hand scraped the front face of the casting. My goal was to scrape it square to the bottoms of the ways on the casting (there has GOT to be a term for these things!) The reason is two-fold: First, I want the back of the casting truly square (where I milled it "square"). This of course is because I am going to use that surface to strengthen the z-axis, and I don't want it to tweak my tram when I tighten it up. Secondly, and this may actually be a non issue, but I thought it would be a good idea to have the front face as square as possible for the ball screws. I figure I might be able to run a tighter backlash tolerance if the ball screw is square to the ways within a few tenths.

As far as the scraping, it went like this; after the initial rough scraping to remove machine marks, and the semi-finish scraping to get a decent bearing, I put the base on my surface plate face down. Then I indicated along the bottom way with my squaremaster (which had already been calibrated to a tenth over 12") I found that the way was off about 7 thou from bottom to top (with the base upright) After a couple hours of work, it was square to a tenth. I wish I could have stopped there, but I had not developed the bearing surface to my liking, (particularly the area where the y-axis will be mounted) so I made a few more light passes just to develop the bearing. With any luck, it will still be at a tenth or two of squareness to the ways when I am happy with the surface.

Sorry there are no pics, but the scraping is enough work by itself. If I stopped to take pics every step of the way, I'd never get anything done!

[TroyO]

I'd say if you are chasing tenths already you've been saving your articulation for the shop, where it belongs.... LOL.

I think I get what you are doing RE: the front and ways. (And the back square being square, etc. I haven't started going at mine in anger yet but I intend to do something similar. Keep at it!

I'm kind of stuck myself... most of my stuff has been AL which is easy to cut with woodworking tools but now I have huge 1" thick chunks of steel to cut which is a PITA, LOL. I have a dual cut saw, which will do it, but not very cleanly... same with a sawzall but not cleanly and not as fast. Tried milling it out but chunked (2) 1/4 end mills....

Yep, I need a Horiz/Vert metal cutting bandsaw. Must have, not optional... well, not that I'll admit to, anyway.

Now, I'm just figuring out how to sell it to SWMBO (She Who Must Be Obeyed)........ :argue:

(Hey, I have a coupon... that should help., right?