The Shop > Tools

The Sajo mill is here

<< < (25/32) > >>

Trion:
Thanks for the kind words guys :)

To answer some of the more technical questions:
- The bearings and the internals of the entire gearbox are only lubricated by grease. Recommended lubrication on the grease nipples are once a day in full time production, that's why I figured it might be a good idea to lube them up at once. The main bearing seems to come short on the daily lubrication, therefore I am extra carefull to get this one greased up before assembly.
- I have checked, the gear still needs to be hammered to slide on the shaft, even though the key is not fitted, so the internal diameter of the gear is a bit too small.
- I believe I have not explained the assembly of the head thurhoughly enough, will have to take more pictures as they say more than wat I am ever going to be able to explain. Briefly, the main bearing is tightened against a flat ball bearing. Both bearings sit in the lower part of the head, and the main bearing is tightened by turning the big threaded ring sitting beneath it. The flat ball bearing has one side facing the main bearing, the other side faces the lower part of the housing. The main bearing may therefore be tightened without the upper (regular roller bearing) ever being mounted, as the entire tightening is done in the lower part of the housing. The top bearing is a roller bearing as said, but it has no lip to take axial forces. In other words, The inner ring and the rollers may be pushed out of the outer ring only by the force applied by one finger. I believe this is made that way to allow for movement, when tightening the gear adjustment screw.
- I like the idea about lapping the inside of the gear to make it a tight sliding fit. This would ease assembly, disassembly and tightening. But then I would have to learn how to lap first ::) Input is much appreciated! :nrocks:

Trion:
Made some more slow but steady progress :)

Sanded down the housings and started masking them




Here's the main spindle assembly, hopefully my explainations about how it is assembled makes more sense now ::)


The flat ball bearing is located where the grease comes out. The ring with a bigger OD above it is laying against the inside of the spindle housing


Somewhere in here :poke:


Both housings and a cover sanded down, washed and ready for paint. Yup that's an original Porsche 944 desktop paper I'm using as bench protection, old rubbish.. If it only were nissan ::)


Here the housings have all gotten their first coat of paint :)


Then I turned my attention to the gear which had a very tight press fit on the main shaft. Since I know little about lapping and how to get about increasing the internal diameter of the gear, I decided to reduce the diameter of the shaft instead. I though about turning it, but when I chucked it up in the lathe I got minimum 4/100mm of runout on the surface to be turned. This was very far away from the chuck, much closer to the tailstock, and I don't know how to adjust runout when something is aligned on the live centre. Considering that I only wanted to remove about 1-2 hundreds, I started looking for a better(?) solution
I decided to chuck the shaft in the lathe, and to sand down the surface in question, but first those new bearings needed to be protected from dust and such..


I used 120grit paper and WD-40


After many attempts I finally reached a tight sliding fit on both the bearing and the gear (with the key also fitted)


Now a few coats of paint remain, then it's off to the assembly line :D

cidrontmg:
You sure go to some lengths with the rebuild. It will be (and look) better than new when you´ve put it together again.  It´s a nice mill, although in my shop, it would fill the entire floorspace, and would have to be operated from out of doors   :)

Trion:
Thanks! :)
I see what you mean, when I'm buying/building myself a house, there is no way around having a proper size garage! ::)

I was just out and applied the third coat of paint just now. I thought I'd get a better surface using a roller brush, but instead I ended up with loads of small hairs in the paint :bang: If it looks too bad, I'm going to sand it down and apply another coat with the trusty old brush. After all, painting this is not something I plan on doing again the next 20 years..

Trion:
Beware, many pictures to follow :borg:

Here are the housings after three coats of paint


I used a fluffy roller brush on the last coat, and unfortunately it lost many of it's hairs to the paint :bang:


But, I was anxious to get it assembled, so I removed the paint masking


Cleaned all the parts and lined them up


Outgoing side of angular housing assembled. What worries me is that the bearings of this shaft have no means of additional lubrication as the machine is being used, while the other two shafts have grease nipples that lead grease in to the middle between the bearings :scratch:


Then I put the housing on wooden blocks and assembled the ingoing shaft as well


Next up was the main spindle assembly. I had gotten hold of some more grease and lubed up the bearings before assembly


Then I laid in the gear, before I put the shaft in, slid the gear onto the shaft and was able to start tightening the spindle bearing nut


Here you see the gear lurking inside its housing :borg:


Here's a view from the top, without the top bearing in place


Before continuing with the assembly of the main spindle, I had to put the two housings together


Then I found the top bearing and cleaned of the hard oil with some wd40. I hope this picture explains what I mean about roller bearing without a locating edge.


I used the cut inner ring of the old bearing to carefully knock the new bearing in place, after having knocked the outer ring in first.


Quick trial fit of the assembled head :)


Then it was time to get the quill head of


A bit of fiddeling later, the new head was finally on


I managed to damage the paint a bit during the mounting as it is just at the limit of what I can lift by myself. :hammer:


Before doing anything more, I let the spindle run at 110rpm for a minute, then I tightened the top and bottom bearing nuts.


Out of interrest, I got the dial indicator out, to measure the runout of the spindle with the ER32 collet chuck mounted


On one full revolution I only had 0,01mm of runout, and that might also be from the outer surface of the chuck :beer:


I dug out the little MIG welder and tacked the previously broken T-slot bolts together again


Put them under the vise and dialed in to within 0,02mm. (The surface I measured on was not perfectly flat so it was difficult to get an accurate reading)



Then I figured I had to set the tram on the mill, so a tramming tool was needed. I found some random steel rod and put it in the lathe


After a bit of turning I had a shaft with a <10mm shank


I planned on cutting of another section of the same shaft and mill it, but I got too carried away, so I just put the newly turned part in the vise ::) I guess I'm not getting any awards for proper milling setup either :lol:


Just out of curiousity, I tried milling a flat on top of the bar, to aid in seeing how straight it was mounted and to get an idea of how the tram was


After having knocked the bar to a semi horizontal position (lacking parallells), I chucked up the centre drill in the collet chuck (lacking drill chuck) and drilled a hole for the dial indicator location.


Then I drilled the hole with a 7,5mm drill, before I stepped up to a 8mm drill to get close to the final size


Then I flipped it over, and again by eyesight measured that the new hole would be somewhat perpendicular to the previous one.


After having centre drilled the hole, I drilled it to 4,5mm to allow for good space around a M4 screw. I also made a relief cut with the hack saw, but it was so tilted I don't dare to show it here ::)
Since I had drilled the original bar, I had to turn up another one. I grinded it a bit on the end, making the parts ready for welding


The MIG welder was used again, and here's the result


I also welded a M4 nut to the back of the tool, as this was much easier than trying to tap the poor thing


And woila, the tramming tool was ready for use :)


It was a bit of a pain to tram the head as the tramming tool was offset from the centre of the boom and gravity only wanting the head to rotate in one direction.. But after some swearing, I managed to get it pretty close to straight. From what I could red of my dial indicator I was about 0,01mm of when I settled with it. But my table has a very rough surface so it was hard to measure accurately.


Now that everything seemed fine, I lobbed up a piece of odd shaped aluminium in the vise and felt ready for milling :D


My first chips (with the vertical head) :)
But I must admit, I'm a lazy bastard. I only turn the handwheels for positioning of the tool, then the auto feed does the rest of the job :coffee:


I cut the surface back and forth with no thought about climb milling or other stuff, just to see how the surface would look


It's a rough one. The depth of cut was definetely the largest to the right, where the marks also are the largest. There is a noticeable ridge between the paths where the tool has traveled. Not quite sure what the cause of this is



Previously I had tried to measure the table wear by putting the dial indicator on like this and then pushing/pulling at the end of the table (as to rotate it arond the vertical axis), and I got 0,48mm of indicator movement. I also tried putting the indicator on top of the table, lifting/leaning on the end of the table. The indicator traveled 0,50mm, accompanied by a squishing sound as from an oil film being broken :bugeye:


When doing this test, I had not locked the Y- and Z-axis (not that the Z-axis lock is working anymore anyways) so the measured movement probably comes a bit from each axis.
I thought about adjusting the table gibs, so I cranked (not really, I used the rapid power feed ::) ) the table to each end to look at the adjustment screws.
On the small end of the adjusment gib, the screw is unscrewed until it stands against the lubrication pump housing.


On the big end, is is adjusted as far in as possible. My only option seems to be shimming..



I thought it was time to try making some T-slot nuts, but only found a stainless plate in the suiting dimension. So I tried milling the top of it, before I called it a day.
I need to think out a way to make those nuts without having neither parallells nor a clamping kit :scratch:



Todays questions:
- Where can I buy a 0,20mm shim that is 400mm long?
- What can cause the ridge on the milled aluminium part?
- How can I make my mill table flat and shiny?

Navigation

[0] Message Index

[#] Next page

[*] Previous page