Thread: Rossi Universal Mill

Originally Posted by Toggy

The Lambo/Maser has just turned into a clapped out Alpha.

Hey, I'll have you know my clapped out alfa now has a new V6 engine.... so there!

As far as the repair goes, forget the loctite... a proper repair is what's needed. How big is the part?

The reason I ask is that we are soon going to get some cast iron castings done over in Ballarat, if you can get a pattern sorted it would be a better fix.

You already have all the machinery needed to make a new part.

Regards
Ray

Hi Ken,
Thats bad news. Is the gear in the first pic damaged? I would get it welded too, as long as there is enough of the original break left to ensure correct alignment.
At least its not full of rust.

Cheers,
Ew

Ray,

Broken housing is currently bathing in the kero tank.

It is about 130H X 130W X 180L. Not only is the transfer "case" for the 3 power feeds; it also houses the leadscrew nut and off the right side is an extension housing that the power shaft for the cross & vertical feeds runs.


Ewan.

That pinion top tooth is chipped. About 1/3 of the outer surface is gone. They appear to be hardened fine toothed helical bevel gears; most likely module. I don't like my chances of finding such beasts. During the rebuild stage I may have to make up some hardened spacers and surface grind them to close up the tolerances and gear mesh. The bottom crown wheel has a few rough teeth I have seen after its bath. Comes from bouncing around on its pinion as they are in separate parts of the housing. They should clean up with a slip stone.

As to the chipped tooth; I think that with the correct gear mesh there should be enough contact area. It has to be OK as it operated the way it was.

Ken

Hi Ken,

How hard would it be to make a pattern, and would it need complex cores? If nothing else, casting a new one is another option.

Regards
Ray

Ray,

If I was to go that route I wouldn't bother with cores. Probably cheaper without the complexities.

Ken

Originally Posted by Toggy

Ray,

Broken housing is currently bathing in the kero tank.

It is about 130H X 130W X 180L. Not only is the transfer "case" for the 3 power feeds; it also houses the leadscrew nut and off the right side is an extension housing that the power shaft for the cross & vertical feeds runs.


Ewan.

That pinion top tooth is chipped. About 1/3 of the outer surface is gone. They appear to be hardened fine toothed helical bevel gears; most likely module. I don't like my chances of finding such beasts. During the rebuild stage I may have to make up some hardened spacers and surface grind them to close up the tolerances and gear mesh. The bottom crown wheel has a few rough teeth I have seen after its bath. Comes from bouncing around on its pinion as they are in separate parts of the housing. They should clean up with a slip stone.

As to the chipped tooth; I think that with the correct gear mesh there should be enough contact area. It has to be OK as it operated the way it was.

Ken

Hi after your tooth clean up might be possible to lap them in by running the gears together with lapping compound of course avoiding any in the bearings.being a rare machine one would think replacements be non existent and if so prohibitive cost. they will be hard as and like car final drives they are lapped in a dedicated machine.There used to be a place in Richmond vic that would lap gears but trail long gone and maybe them too. There is another fellow Ivan Albins in Ballarat who makes dedicated sp bevel gears.should be on the net web site. Don't forget to allow back lash when finally assembling maybe run in for a while and reset. just a little constructive input I hope John.ps larger gears we give 003-005'' back lash that is with ep oil.

If all else fails would a pair of off-the-shelf straight cut bevels be a replacement option?

Wow; how time flies.

I have been working steadily (I am not as quick as Ewan or Josh) on the mill. Stripped it apart and started building another from the kit.

The Italian Stallion quickly turned into a gelding with that knackered casting and now the wife calls it my Italian mistress because I spend so much time with it.

Over the last few weeks I have been plugging away at the repair. Basically had to re-engineer the assembly from the bits. I eventually machined back the larger block of the casting which had flat reference surfaces milled on it from original. I then made a new base out of steel which was a slow process as the only piece I had of suitable size was a block of Bohler M200 which is a heat treated/pre-hardened toolsteel for plastic injection moulds. To complicate things there are oil galleries within this base.
I didn't realize that threaded holes were so costly; $75.00 for 15 of them. Well that's what the 4 new HSS taps cost. I wasn't going to chance breaking an old tap after all the hours spent machining. Most of the bearings have been replaced with the biggest culture shock being 2 angluar contacts on the knee. Quoted $217 ea plus postage here. Finally got 2 SKF from the States for about $120 the pair delivered. That is a huge saving.

Today I dry fitted the lot into the mill so that I could mark out the fixing bolt holes. Mounting holes drilled and tapped and oil galleries drilled. There are 3 sets of bevel gears held within this assembly and it has ground spacers to set backlash. Several of the spacers will have to be ground and at least 1 new one made. Funnily enough this is to allow for wear; not my rebuilding.

Now to find somebody locally to TIG weld some chipped gears. They are hardened; so I am thinking of using 316 SS. Harder than MS.

Some pics of the repair parts.

KenP1010281.jpgP1010282.jpgP1010283.jpg

Hi Ken,
Very nice work. I think what you have done is probably the best way out of the problem, but it must have been hard work with that block of m200, that stuff is tough.
Off the shelf bevel gears may still be cheaper than getting the others welded. I wouldn't be to worried about having straight cut gears in the knee. I don't know if you have a surface grinder? If you need anything done i still feel i owe you one, i'm only a 500g satchel away......
The Vernier was the same with bearings, most were in the $10-30 range, then one in the uni head was $400+another $80 or something for the race!

Your lucky your wife thinks you only have one mistress, mine thinks i have 5 or 6......

Cheers,
Ew

Hi Ken,

Nicely done

I think that approach, that is, of making a new part is the one that makes the most sense, rather than trying to weld CI, and the new part will be much stronger...

Did you get any further insights to what caused the crash, was it just some over feeding on the Y axis power feed in it's previous life?

Regards
Ray

Hello Ray.

As Josh pointed out there were 2 different repairs done to the casting. All 3 breaks at about the same weak point. Oh, to have CNC machines and the smarts to drive them. Would have been much quicker; though I have been able to almost exactly replicate the dimensions. Sneaking up on those .001mm I found hard.

I had the unit mostly stripped when Joe and Peter called in. By this time I had ascertained that the knee left screw is very long to gain the 18" lift. It is only a single stage screw and extends well below the base of the machine. I have read that in this case there are 2 options; raise the machine or drill a hole through the floor. As Peter said, it appears to have had the screw over a hole before as there was a rust mark on the lower part of it. Knocking a hole in the floor here is not an option because of occasional flooding and because the screw is on the lift point for the pallet trolley. Low roof excludes a fork lift; so sill make a trip over to Rich River and get some 100mm rhs. Will that mean she is tall & willowy instead of short & dumpy????

There is no evidence whatsoever of any other damage or bruising and there is 1 vertical adjustable travel stop missing. I am guessing that on fast travel the screw has slammed into the floor and trying to lift 2+ tonnes has done the damage. I think that the chipped gears have happened after the breaks and still trying to use the power feeds. I don't know yet if any of the travel stops are faulty; as I clean, repair/replace as needed each part then refit.

Ken

A bit more progress today.

Transfer gear assembly dry assembled and fitted into knee. Lead screw and drive shaft fitted to knee and repaired assembly. It is getting crowded in there.

There is clearance between the transfer assembly and the knee housing and gear. Repaired unit fitted to lower section of universal table. It has gone back in the same place, but the pinion gear is not meshing correctly. The pinion shaft fits in a set place within the drive gearbox; but if need be I will just have to make a replacement shaft to set the pinion over a tad. I found that some idiot had previously placed a locating dowel in the oil gallery. Then the leadscrew covers have been ditched no doubt to gain access for lube (used diesel oil).001.jpg002.jpg003.jpg007.jpg006.jpg

Those eagle eyed ones may have also noticed that the poor old girl is turning grey with age; after all she is nearly50. Another thing I found was that the lower section of the knee casting was filled with fine oily sand. After cleaning it out I found that the sandy area was unpainted. How did that casting sand stay there with all the machining operations. Obviously we just can't blame asian manufacturers for being slack.

Ken

Originally Posted by Ueee

Hi Ken,
Very nice work. I think what you have done is probably the best way out of the problem, but it must have been hard work with that block of m200, that stuff is tough.
Off the shelf bevel gears may still be cheaper than getting the others welded. I wouldn't be to worried about having straight cut gears in the knee. I don't know if you have a surface grinder? If you need anything done i still feel i owe you one, i'm only a 500g satchel away......
The Vernier was the same with bearings, most were in the $10-30 range, then one in the uni head was $400+another $80 or something for the race!

Your lucky your wife thinks you only have one mistress, mine thinks i have 5 or 6......

Cheers,
Ew

My Italian mistress[Diatto]wears expensive shoes 800 dollars each.6 four on the ground and two spares.Her proposed major surgery is on hold[2 piece crank] for a while.She's not bad to sleep with got soft pig skin upholstery.With a shed filled with unsatisfied ''tarts'' its never dull around here.A terminally ill sufferer of old car and machinery pox. John.

Originally Posted by Toggy

A bit more progress today.

Transfer gear assembly dry assembled and fitted into knee. Lead screw and drive shaft fitted to knee and repaired assembly. It is getting crowded in there.

There is clearance between the transfer assembly and the knee housing and gear. Repaired unit fitted to lower section of universal table. It has gone back in the same place, but the pinion gear is not meshing correctly. The pinion shaft fits in a set place within the drive gearbox; but if need be I will just have to make a replacement shaft to set the pinion over a tad. I found that some idiot had previously placed a locating dowel in the oil gallery. Then the leadscrew covers have been ditched no doubt to gain access for lube (used diesel oil).001.jpg002.jpg003.jpg007.jpg006.jpg

Those eagle eyed ones may have also noticed that the poor old girl is turning grey with age; after all she is nearly50. Another thing I found was that the lower section of the knee casting was filled with fine oily sand. After cleaning it out I found that the sandy area was unpainted. How did that casting sand stay there with all the machining operations. Obviously we just can't blame asian manufacturers for being slack.

Ken

Hi Ken,when you have your mesh of gears right any thoughts running them with a jury rig set up and re run them in with a lapping paste?the bearings could be isolated to avoid contamination A good 2 or 3 hours running wash out occasionally and replenish paste and oil mix.
Without personally inspecting the gears would leave them as they are and run them not build them up.if it is shimmed up and back lash is correct.Spiral bevels are stronger than straight cut due to extra length of tooth.Cheers with 2 cents worth John.ps very nice machined job too.