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Deckel FP2 Gib Wear

Nigel Tudor

Plastic
Joined
Aug 6, 2018
Last fall I was fortunate enough to buy a Deckel FP2 (serial number 8800). As has been recommended several times on this forum, I disassembled the table/saddle to make sure that no one ever pumped grease into the oil lubrication ports. Luckily it appears that my machine was never given grease in the oil ports.

The way surfaces on my machine appear to generally be in good condition. The major exception is the gibs that bolt to the back of the table. Measuring on the “unworn” part at the ends to the center, there is about .0008” (.002mm) of wear on the table back gibs. The mating surface to these gibs on the knee still has some scraping marks in the center and is worn .0001” (.0025mm) lower on the operator side and .0002” (.005mm) lower on the side away from the operator. I think the previous operator just gave it a couple of squirts of oil and didn’t fill up the sight glass. Luckily there is no galling.

I have a surface grinder (6 x 18) and plan on grinding and rescraping the back gibs. Here are my questions:

1.)I have read that the gibs are made of steel and not cast iron. Can you use a 5 degree negative (like cast iron)to scrape these gibs or should you use a positive cutting edge? Do you have an angle recommendation?
2.)At a minimum I am going to restore the back gibs.
3.)Is the wear on the saddle side low enough that I can leave it be or should I scrape it parallel to the front side (which appears to have minimum wear).
4.)What clearance would you recommend for this gib?
5.)The scraping is not particularly deep .0002"-.0003"(.005 -.007mm). It appears to be the half crescent or "Moore Style" scraping pattern. I don't know how to "Moore Pattern" scrape. I would checker board scrape the surfaces as I learned from Richard King. If I rescape these surfaces is just the scraping sufficient or should I also frost one side (probably the saddle side)?

Here are the gibs sitting on my surface plate:
deckel-fp2--table-back-gib.jpg

Here is the back of the saddle:
Deckel-FP2-Back-of-Saddle.jpg

It was hard to get a picture of the back of the gibs that go on the back of the z-axis column ways. There is only .0001" wear on the upper side of these gibs. On my machine the way surface sit .0029" (.073mm) higher than the ground surface that mates with the saddle.
Deckel-FP2-Saddle-Back-Gibs.jpg
 
I figured while the mill was apart I would scrape the way surface that mates to the worn gibs in the above post. This way surface which is only 15mm wide (.600”) holds back against the leverage exerted by the work and attachments that are placed on the mill table. The way on the opposite side sees very little force and was in top condition. I used a micrometer with a .200” croblox as a scrapers block (to bridge the high points on the front face) and mapped out the wear and checked my progress as I scraped.

Deckel-Saddle-Way-Measurement.jpg

When the surface was within a .0001 (.0025mm) of being parallel to the front way, had decent points per inch and good coverage I decided to stop. Here is the end result:

Deckel-Saddle-Scraping.jpg

Here is a picture of my mill before I disassembled the saddle/ knee.

Deckel-Before-Disassembly.jpg

If anyone could answer my question of the correct clearance to leave on this box way (the gib is scraped to give the correct clearance and is not otherwise adjustable)? Also are these gibs steel ( I believe I read that somewhere on this forum)? Does anyone have a recommended scraper angle (angle of dress on the carbide scraper) that they have found works well on these gibs?

Thanks,
Nigel
 
Nigel, when I redid these on my FP2, I first had them surface ground to the right offset step and then brought them to Franz Singer. One of his scrapers then scraped oil grooves into them, it took about 15 minutes for him. I don't know what the blade angle was, but he dipped the blade into mineral spirits before each cut because he said it kept the blade from skidding. Photos are in my long FP2 support clean-out thread.

(By the way, these steel backing plates are harder than the cast iron that they rub against. You might think that this would lead to wear of the softer cast iron. But it's the opposite: abrasives embed in the cast iron and lap the harder steel backing plates!)
 
If anyone could answer my question of the correct clearance to leave on this box way (the gib is scraped to give the correct clearance and is not otherwise adjustable)? Also are these gibs steel ( I believe I read that somewhere on this forum)? Does anyone have a recommended scraper angle (angle of dress on the carbide scraper) that they have found works well on these gibs?

I've read that a positive rake is used, 20-30 degrees like a woodworking chisel. Good tip about dipping the scraper. Wanna try that.

EDIT; link to Richard Kings input on this:
https://www.practicalmachinist.com/...eel-what-angles-do-i-need-251951/#post1872423
 
Bruce,

Thanks for your reply. I went back an reviewed your teardown thread (which I had previously read when I bought my mill).

Were they flaking the ground gibs at Singer? Were they hitting the ½ moons in by hand? Thanks for the tip on the mineral spirits.

For the clearance I think I will use gauge blocks to check the unworn part at the end and go up .0001” (0.0025mm) at a time to figure out what the clearance should be. I will post my results so people in the future will know what this clearance ought to be.

I ended up rescraping the saddle side while I had it apart. You can see a picture of the result above.

Thanks for your help,
Nigel
 
Lucky,

Other than this gib and its mating surface there is minimal wear on my machine. The scraping marks were barley visible only in the center of the saddle side and gone on the gib side. Without a place for oil this would lead to stiction and eventually galling. By rescraping the saddle side and restoring the gibs, I hopefully will be restoring the original accuracy of the machine. This wear translated to a .001 droop at the table edge (probably actually .0015 -.002 as the edge of the table should be high) in most of the travel but would lift up at the very ends. Before I took the mill apart I thought possibly someone had stoned a “hole” into the table but once I saw the worn gibs, I knew what the true story was. Lastly I must admit I am a bit of a perfectionist.

Thanks for your question,
Nigel
 
Were they flaking the ground gibs at Singer? Were they hitting the ½ moons in by hand?

Yes and yes.

For the clearance I think I will use gauge blocks to check the unworn part at the end and go up .0001” (0.0025mm) at a time to figure out what the clearance should be. I will post my results so people in the future will know what this clearance ought to be.

Personally I would aim for a clearance of just a few microns. Since it will be a scraped surface on a ground and scraped surface, if there are some high points that tend to bind they will be quickly worn away. Since you are an experienced scraper, if you get the clearance to tight you can just blue it up and knock off another few microns.
 
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Personally if i was going to the trouble of reworking the "Back Keeper Plate Gibs" on the "Z" i would seriously consider fitting Rulon or Turcite......
Advantage is ease of fitting up for good fit and reduced friction and wear....

Later manual and all the FP-NC's went this way....
Kits are available that have glue and hardener...
The sheet stock is available in various thickness.

Further i would also consider applying the Rulon to the top keeper plate gib as well.....

Rulon 142 | Linear Bearings and Slides | TriStar Plastics

Not difficult to work with (sort of fun actually) and it will improve the slide performance....

Cheers Ross
 
Ross,
Thanks for your input. Rulon or Turcite would be a good choice. I have only scraped a little Rulon/Turcite but it does cut like butter and is fun to work with.

The z axis "back keeper plate gibs" only had .0001" wear, so I have already put the saddle back on the machine.

At this time I am only redoing the top keeper plate gib (x-axis). Since I only have to grind off about .002"(.05mm), I think I will try grinding and flaking the top keeper gibs. If it doesn't work as well as I would like I will keep the Rulon option in my back pocket.

Thanks,
Nigel
 
It’s been awhile so, I thought I would post some pictures of the process I used to recondition these gibs and how they turned out. I used gauge block stack at the end of the table where the gibs were unworn to determine the original fit. It appeared that originally there was .0001 (2.5microns) clearance between the ways and the table.

Measuring-Gib-Fit.jpg

I ground the gibs on my surface grinder. There was some tension in these gibs so, I had to grind them on all sides to get them on all sides to get them flat. They went slightly curved after I ground the first side. Due to the length of these gibs and the fact that my surface grinder doesn’t have coolant I had to grind the gibs in passes taking only 20 millionths per pass (.5 micron). If I ground too heavy the gibs would lift up in the center and I ended up taking off too much in the center (coolant probably would have allowed me to grind these gibs more aggressively). I used a gauge block stack to comparatively measure the offset between where the gib clamps to the table and the way surface. Here are the gibs after I finished grinding them.

Finished-Ground-Gibs.jpg

I checked the fit with a gauge block stack that was the thickness of saddle way surface. The table side had .00005” (1.25micron) wear in the center but not on the ends. I kissed off the back of a 1-2-3 block (a sad looking auction item) and used it with 400 grit wet dry emery sand paper to sand down the ends slightly.

Sanding-Ways.jpg

It only took a little while to even up the table side ways. Now the gauge block stack the thickness of the saddle ways moves freely over the entire length of the table, a stack that is .0001” (2.5 micron) larger than the saddle ways moves with a slight drag with a couple freer areas but a gauge block stack .0002” (5 micron) larger than the saddle ways doesn’t fit in anywhere.

Now it was time to flake/frost the gibs. I practiced on cast iron with a Biax #30 blade with a 60mm radius. I held the gibs in a Moore jig borer vice to flake them. The steel didn’t flake as nicely as the cast iron did, but it still worked. I ended up putting a piece of rubber on the vice as I chipped the blade a little one time when the blade came off of the gib after hitting in a flake (something I didn’t want to repeat). Here is what the finished gibs looked like:

Finished-and-Flaked-Gibs.jpg

Flaking-on-Gibs.jpg

This took longer than I thought it would, but I am pleased how it turned out. It also didn’t help that I live and work on a farm, so with the arrival of spring, my free time to work in the shop is rather limited.
 
Nigel,

You did a nice job of this, thanks for posting the photos.

One comment: these parts should be called "backing plates" rather than "gibs", because gibs are adjustable elements whereas these backing plates are fixed.

I am curious about one other point. Your machine should have one or two tapered gibs along the X axis. Did you do any work on those, and the corresponding bearing surfaces? Or were they in good enough shape that it wasn't needed?

Cheers,
Bruce
 
Bruce,

The X-axis gibs look pretty good, so I am going to leave them alone for now. The top gib is the dovetail gib which has some wear in the X-axis lock area, probably from being used by someone who learned on a Bridgeport. The other gib has just a bit of wear at the tip of the operator side, probably from the ingress of dirt. I think the wear on the backing plates was largely from using the mill without adequate oil as that area runs out of oil first. Luckily there was no galling.

X-axis-gibs.jpg

As my machine shop is small I had been working on the mill in another building on my farm. I just moved it into my machine shop. I thought I would include this picture which you could title either “color coordinated equipment” or “moving a Bavarian mill with a Bavarian tractor. I moved the mill without the table on it, to minimize how much other equipment I had to move to get it into my machine shop. I am sure as I finish putting my Deckel back together, I will have other questions for this forum.

Moving-Deckel.jpg

Thanks,
Nigel
 
That's just a regular tractor to me, but I live in farm country. The smell of cow dung is everywhere now, that smell means it's spring and the farmers are fertilizing the fields.
 
The tractor is 120hp, which in the scheme of things is relatively small for a modern farm tractor. This brand of tractors make up to a 500hp tractor which uses the same size tire on the front as my tractor has on the rear. I am glad that I was able to use my tractor to safely move my FP2 into my machine shop.

Thanks,
Nigel
 








 
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