The Shop > Tools
The Sajo mill is here
Artie:
Before I made any decisions regarding the fate of the machine Id find out exactly what, if anything, is wrong with it. It may well be 'normal' for the beast. Mine annoys the hell outta me but I know that many of its type do it and I also know that quality bearings will make it much quieter..one day...
Do you know of any repair or service company that has experience with this brand? Maybe they would be willing to talk to you about whats good and whats not. Talks to sales companies they may be able to point you in the direction of others who can help. Is it easy to have a look inside the heads?
Only once you know what the cost is going to be can you determine if cutting your losses is acceptable and move to another machine as opposed to repair this one.
Good luuck... that looks like a nice machine... I hope its got life left in it yet... :thumbup:
Rob t
Artie:
You say that you cant feel any bearing wear so you are afraid its on the gears.... in my experience, for a bearing to be noisey it doesnt need to exhibit wear or free play. Its often impossible to check a bearing in situ.... but they can usually be felt as bad things when in the hand... dont discount a simple (relatively) cheap fix yet... :D
dsquire:
Trion
After thinking about this for a bit. :doh:
I have a feeling that it is in the bearings where most of the noise and excess play is coming from. Worn gears might give you some backlash but not side to side. The rumbling that you hear may well be some square balls in the bearing from a bearing breaking down. I would be tempted to put an end mill in and make it do some hard work for a few minutes while listening to it and watching how it acts before I started tearing it apart. Weather its bearings or gears I don't think a minutes hard work is going to make any difference but it may help you pin point the problem. I hope that this is of some help. :D :D
Cheers :beer:
Don
Trion:
dsquire: I've been thinking a bit about it too. If only thetable is moving straight in all directions, then I can replace the bearings in both gearbox and head and use the machine. The gears might still make some noise, but it won't affect the accuracy of the milling, right!? Considering that the machine is going to be used rarely and only under hobby-load, I believe the gears will last many years to come. By the time they let go, I might even have a dividing head and a module cutter laying around ::) Or who knows, maybe they still sell spare parts for this machine?
Selling the machine as it is, I'm either not going to get any money for it, or I would have to fool some poor guy. But I like my wallet thick and my concience being good, so it seems my only option is rebuilding :dremel:
Bernd: The play in the bearings of the angled head is very noticeable. At first I noticed it with my hand, and guessed it was about 2mm. I was amazed to find it was only 0,7mm.
Artie: That is what I'm thinking too. Find out all the bad things and make a decision. There was a repair/spare part company called sajoservice, but they seem to be out of business. :doh:
Having a look inside the heads is going to be a bit of work, but I'm sure it's going to be worth it. Once open, I'm going to replace all the bearings I can find in there ::)
Next up: Making a new pair of t-slot studs and try a bit of milling. Maybe also try measuring the table wear.
Trion:
I have not yet purchased any more milling tooling, so i have not been able to test the mill fully. Althoug i redrilled a pair of brake discs a couple of weeks ago, using the quill head. I only ran at about 300rpm so everything was running nice and quiet, and the drilling was no problem.
Therefore I have decided that the quill head is in best shape and may stay on the machine until the other head is rebuilt.
Here's a picture of the head already slightly disassembled
In order to get the spindle out of the head, first the bearing tightening screw has to be removed
Then the spindle bearing block may be turned out of the housing
But then a problem reveals itself. The gear which drives the spindle is a 45degree helical gear that sits on the shaft with a press fit and uses a key to secure rotation. This gear is too big to exit the housing still mounted on the shaft, and therefore the shaft has to be pressed of the gear and the gear is then to be removed out through the hole which the picture is taken through. Sort of ::)
The shaft may be removed as far as this, but then the gear is stopping it
Big gear vs. small hole :bang:
I tried pushing it out like this, but the "clamp" was just slipping on the bolts I mounted. Will have to improve this fixture to try to remove it again. I really hope the gear doesn't damage the inside of the housing when being pressed off!
After many attemps to remove the gear, i went on to disassemble the the other part of the head
This part of the head uses angular contact ball bearings on each shaft and an adjustment nut to tighten them. The bearings felt quite good, but I figured I should replace them while being at it. It is hard to feel if a bearing is worn without having it in your hand anyways. Here's the housing for the outgoing shaft.
Housing and ingoing shaft
Disassembled
But the inner ring of one bearing kept to the shaft, so I had to think out of the box to get it off
Voila :)
Now off to the garage to try removing the bad gear again :dremel:
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