Tos FN22 milling machine (Deckel clone)

[roofman]

Such a complicated machine this one...great job getting your head around it

 

[Brad93]

How will you ensure you do not change the alignment/geometry of the vertical ways? To the x and the y axis?

 

[Pete.]

How will you ensure you do not change the alignment/geometry of the vertical ways? To the x and the y axis?

Well, firstly there is so little wear that it shouldn't be a problem for the flat ways. Any scraping I do will be done across the whole plane to bring it all down to the bottom of the wear so geometry whould be maintained.

For checking there is that huge flat machined face on the front. It's inconceivable that the ways would not have been machined separately to that bit so all I have to do is setup a beefy dial stand on the face and take readings up and down the ways. These are comparative readings not absolute so the actual reading doesn't matter just the amount it changes I expect that it wil show wear in the bottom half of the flat ways and the top half of the angled ways because of the way the console and table's weight hang on the front.

Once the flat ways are scraped in I can make a jig to measure the wear in the angled ways which will identify the wear in theose and where to scrape. I can also use a precision square clamped to the front ways and a large surface gauge on the top ways to check them for being perpendicular to each other.

 

[Pete.]

Last night I dragged out the wobbly Wellsaw and started cutting up some old channel I recovered from a demolition job some years back. I wnted to make a frame that would hold the main body of the mill for scraping more comfortably than working vertically.



I unbolted the body from the base and turned it around so I could fix the frame to the existing holes.



This evening I finished it off and dragged it over onto it's stand so it's now being very sturdily held at 40 degrees tilted back.



Here it is stuck in the corner where I can get good access both sides for scraping and it's not in the way too much.



Once the frame was out of the way I scraped all of the gunge out of the base and stood it against the wall. Seems to be quite happy just standing there

 

[Pete.]

I did some quick evaluation on the machine starting with stoning the flat face on the front of the machine to get rid of any dings and burrs. The ways look pretty good just from a clean.



I have a ground flat stone for doing this so it can take off any high spots without affecting the main flat face. You can see a great example of how a flat stone works here where I've used it to take off some dings in the edge of the way. I stopped to take this photo because if I had took it all down with the stone it would not have shown it so well.



Then I used a half-tenths reading digital gauge on a chunky comparator stand to see what state the ways were in compared to the front flat. Yuo really need a sturdy stand to do this properly you can get away with a surface gauge type stand but it's easier with a heavy one if you have the room for it.









Remember these are comparative measurements they are checking the difference between the front flat and the working ways - they should have been machined at the same time and the flat front should be flat and straight because it's done no work at all but you can't take that for granted.

So the ways look at first to have about 2.5 thou of wear towards the bottom and most of it in the bottom half with very little in the top half. This makes sense when you think that the console and table hangs on these ways. The weight will tend to pull the top away from the ways, so you would expect the flat ways to be worn at the bottom and the angled ways to be more worn at the top.



I will have to do more checking on the state of the ways before I commit to any scraping. I will check the flat front and the ways themselves with a straight edge and if they all check out I'll start to work on scraping out the small amount of wear.

 

[RichardM]

The stand reminds me on Papa Lazarou

 

[dobbslc]

Dave?

 

[Seadog]

She's my wife now...

 

[Pete.]

I've had to work both days this weekend but I've managed to get a couple of hours of scraping in. I got the z axis/console slide stripped down which was a bit of a trial in itself during the week and did enough cleaning so that I could evaluate the flat ways. First thing to notice is that just like the y-axis ways there is a significant centre dip scraped into the ways. As metioned before this is done deliberately so that as the ways wear they wear 'in' not 'out' in other words as the ends of the ways wear (they are always the bits that wear fist) it doesn't start rocking on the centre section because it's already lower han the ends. It's possible that there may also be the benefit that the centre will hold oil in the scraping pockets which again will keep overall wear to a minimum but that is just conjecture on my part.



My 18" x 12" surface plate is a good fit for printing so I'm using that to blue the part for scraping. First print shows contct in only 3 places. Some heavy scraping required.



Here's the progress gained from a 2-3 rounds of heavy hand-scraping between each pic taken.





These pictures were over a span of an just over an hour and a half so even though there wasn't too much contact at first it didn't take a whole lot of work to really bring the bearing in well. I have a bit more work to do on it but I won't be scraping it so much that it prints right across, I'drather presrve that low spot in the middle seeing as how it appears to be working so well.

 

[roofman]

Very surprised how a lateral moving part can wear so much over time..guess the secrete to longevity is oil,oil,oil on the ways.

 

[daedalusminos]

Are they shaper tooling marks in the recess?

 

[Pete.]

Very surprised how a lateral moving part can wear so much over time..guess the secrete to longevity is oil,oil,oil on the ways.

You need oil but you also need somewhere for the oil to be. In the first pics you can see that the blue is smeared out thin and the faces top and bottom very shiny. The same happens to the oil, the shiny smooth face squeezes oil out very quickly which is not very desirable - you want the oil to stay where it's doing good. That's why scraping and oil flaking is good for a moving way, it leaves tiny pockets for the oil to sit in and lubricate the way as it passes. The way is a combination of oil pockets and bearing surface.

Are they shaper tooling marks in the recess?

Shaper or planer yes.

 

[Pete.]

So, back in post #345 I took some measurements that suggested there was 2.5 thou wear in the ways at the bottom, but there were a couple of things that were bothering me whilst doing the checks. The slides have oiling grooves cut straight along the ways. Machines these days have angled oiling grooves because the straight ones leave a ridge down the way. With 2.5 thou of wear there should be a very pronounced ridge towards the middle of the normal travel however running the DTI over the barely visible ridge it was only raised a tenth or two of a thou. The same goes for the edge of the ways, the slide doesn't quite reach the edge on one side so that bit should never see wear and so 2.5 thou of wear should leave a 2.5 thou ridge but it didn't. Another thng that I noticed was that wherever the reading changed on the working section of the way, it also changed on the un-worn section of the tiny ridges. This could only mean oneof two things - either the entire way was out of flat or the part that the DTI base was sliding on wasn't flat.

Well, today I got my 4 foot straight edge out and did some checks. I keep this very nice heavy pattern Windley straight edge only for checking other straight edges or the odd job like this because I got it completely un-worn and want to keep it as a good reference.



I put the straight edge on the way and it prints blue at both ends and in the middle, so the way MUST be straight. There's not much transfer but enough to tell a story.



So I turn my attention to the flat face that I was taking measurements from. This also tells a story - that face is certainly not straight.



Now I'm wondering if having the casting leaned back on my stand is affecting it. Doubtful but you gotta know so I stood it up and checked again.



The face is definitely out of whack so I blued up a small surface plate and printed the top then the bottom half separately.





So there you go - it wasn't wear in the ways I was measuring - it was the front face being miles out of flat. Good news for me because I have a lot less scraping work to do.

 

[Pete.]

How will you ensure you do not change the alignment/geometry of the vertical ways? To the x and the y axis?

I also this evening jigged up a setup to check the Z and Y axis relationship. There are 2 things to consider when doing this - that the Z axis travel is exactly perpendicular to the Y axis travel and that the table top when loaded is exactly parallel to the y axis travel. Here's my setup for checking the ways are perpendicular. This is the easier part because the ways are fixed and all you have to do is make sure that they ARE exactly perpendicular. The second is not so easy because the more weight you put on the table the more it will droop so you just have to scrape-in an allowance and take a happy medium. Thankfully the (comparatively) massive ways on this machine mean that it's very stout so droop should be minimal.

I already know from the checks above that the ways are pretty damn straight so I set my 48" straight edge on the way and put a small bolt to hold it in place just in case I knock it. Then I took a granit square and rested it on the Y-axis way with a mag base for a backstop. I also put some tiny neo magnets on the casting coz I was paranoid about knocking the granite square off and smashing it.



I got a surface gauge which has the sliding pins in it and fitted it up with a tenth-reading Tesatest indicator.





Using the pins is very important for getting a consistant reading when doing something like this. I did try it a few times just free-hand but the reading just wasn't as steady. If you have ever seen one of these with the pins fitted (or holes) now you know what they are for



And here is the result. Not even a tenth of deviation over 150mm (which is nearly half the Z travel. Can't complain about that.

Dropbox

www.dropbox.com

I will have to check the alignment again for both sides as I scrape the ways in to make sure I am not turning the ways, but TBH it's unlikely with the small amount of scraping I'm going to have to do.

 

[Pete.]

I've been scraping the main slideways, really got stuck into them this weekend. I'd made the lean-back frame to make measuring and scraping the ways easier but I was still struggling when scraping diagonally 'downwards' on one side, the awkward body position made it difficult to keep the Biax scraper held at the right angle and I kept gouging the metal with the edge of the blade, plus the effort of holding the straight edge at the angle eventually made me pull a muscle in my back, hence the lack of updates.
So I modified the frame with an extra leg that allowed me to tilt the casting right up horizontal and also welded some channel to my bench edge to hold the wonderful 30" straight edge made by @pressbrake1 and got on with it.

Whilst it was on it's feet I had rough-scraped both sides:



Then after I got it up on the flat I could make a proper job on the RH side. Got a nice even spread of blue spots



Here's a few shots of the finished work







I've started on the LH way already should have that done today then on to the angled ways.

 

[awemawson]

It'll be better than new when you've finished Pete,

I hope that the back recovers.

 

[Pete.]

It'll be better than new when you've finished Pete,

I hope that the back recovers.

I dunno about that Andrew but I'll do the best I can. It'll at least be a fine working machine.

I really want to scrape that front face too but I don't relish the work involved as it'a alarge area and it''s quite badly out of shape. It sure would make for a nice reference surface when setting up work or setting the 3-angle table though.

If it wasn't so damned difficult to move I'd take the whole casting over to @pressbrake1 and get him to indicate off the scraped ways and plane the front flat.

 

[Seadog]

 

[Milkybars]

@Pete. I am sure we could take it through the house

 

[Pete.]

Scraped the left hand side. At first I found that the straight edge was hinging in the middle, obviously had a slight hump in the middle which I had to get rid of first. I scraped the middle down a couple of times until it was bearing heavier more towards the ends. We are not talking about much here probably 0.0003" or so. In this pic you can see where it's printing lighter in the middle wher eI double-scraped it to get rid of the hump, heavier just either side of middle and the ends I've left rough-scraped so the pattern is not so good.



I worked my way towards the ends to get a nice even bearing. It's pretty good now, well about as good as I can achieve anyway. This whole way is now straight and flat to about 0.0002".



Here are both ways finished.



After dinner I am going to 1. check them for squareness to the y axis and 2. scrape in the slide that goes on them a lot better against a surface plate then 3. Use the scraped slide to check that these ways are still planar to each other. I don't expect it to be perfect but I don't expect it to be far off either.