and so it begins......

[moose]

Can you make a quick sketch (by hand or in paint or whatever) with how you want the axle to work?

Welding a live axle together will be challenging... That same SKF page quoted a shaft straightness of something like +/- 0.25mm (over some length, maybe arbitrarily between two bearings)

If you are welding the whole thing together, you will need to sleeve it somehow. I would make the ID's of each shaft equal and use a plug (drill holes away from butt joint and fill with weld). This will add strength and move some stress away from the butt joint. A few more questions:

What are you going to weld with? (TIG/MIG?)

What is the longest you can turn center-center on the lathe?

Fabroman did bring up a point- turning the work at a higher rpm and moving tool at a slow feed should give you a nice smooth bearing surface. Match the tool and work speeds to the cutting speed that is recommended if you arent sure what to start at.

 

[davidbooth1991]

Hey guys...
So here are some pics of my axle ( moose I hope this helps I'll try to do a sketch if I can find time ...the workshops abit busy at the moment)

So... The original ATV axles thickest part is the part after the disc splines ( I've cut the axle in half ). I will be able to get my 30mm bearing through there with no problems. My extension however needs to be turned down. I'm going to weld prep, route run clean it out and cap run it then clean it up good I'm using a 425 amp mig plant. (Obviously not set to 425 amps in case there's any learners reading that's just the plant I use).

I'll need to turn it down about 250mm in from each end as the back of my kart is about 425 were I can fix the bearings on. I'll take a better pic tomorow to help explain things better.
Many thanks guys I'll fill you in tomorrow.

 

[davidbooth1991]

So I got to work today and the boss was sat there in his chair with his tea with a reasonable look on his face. So I asked him if I could use the laithe. ( the laithe isn't in the workshop I use its in another down the road).
And before I could breathe he said no.
Some bafoon has managed to shatter all the gearing to the chuck so I can't grip any work pieces.........

 

[davidbooth1991]

Does anybody happen to know of a way of instaing a CVT on a buggy. I have a Genny engine that has a keyed 19.5mm drive out put, I could just put a sprung clutch on but it won't last long going by other info and experience on the forum. All the variator and clutches I've seen all have much smaller drives and I was wondering if there is some sort of way to put a CVT on a buggy??????? I don't really want to machine the crank.
Cheers guys

 

[OzFab]

By "genny engine" can I assume you're referring to a clone?

19.5mm is a strange size for a PTO shaft, they're usually 19mm, 20mm or 3/4" (19.05mm); to fit a torque converter, you'd either have to bore the driver (which I don't recommend) or machine the shaft...

Having said that, a series 20 or 30 driver are usually 3/4"

 

[redsox985]

That seems like alot. I would bring it to size (30mm, if thats what the bearing measures), then try the bearing. If it doesnt fit (it might), take the smallest cut you can, just *touch* it, moving at a reasonably slow rate(tool travel speed). Use ebony cloth to smooth the shaft after. I would be surprised if it took more than a couple cut-check iterations. Resist the urge to hammer the shaft into the bearing.

Goodluck!

http://www.skf.com/group/products/b...mer-block-units/internal-clearance/index.html

SKF has some clearance tables that would suggest that the shafts should be exactly to size. Take off that 0.17mm (or whatever) carefully.

... also if you measure 30.17mm, is there a chance that its actually 1 3/16"? I guess weigh the cost (time/money/aggrevation) of machining vs cost of new inch-bearings.

Ok guys I really appreciate all the help and advise. Moose....
My axle is splined to take the discs, it's 29mm after the splines. I'm extending it with 30mm bar to get the length I need to turn down the centre piece to get my bearings on. I'll take some more pics and go in to more detail if you need me too. Im going to turn down about 250mm in from each end as that is where the bearings will sit. Do you think this is the right way to do it guys????? Thanks again.

Though I'm a bit late here, for future reference, I'd start with something like 80 grit sandpaper just to knock the scale off and see what OD the metal actually is. Then, I'd try to measure with a micrometer if at all possible. Next in the hierarchy would be a high quality set of digital/dial calipers, or verniers. Then, last would be the cheapo sets you can find anywhere.

If these will be retained with lock collars or some other mechanical fastener, a "zero fit" should be your target... + zero, - zero on the measurement tool. If it's not being held mechanically, a rough estimate on pressfits (at least with steel to steel) is .001" per inch of shaft/bearing. A 30mm shaft (1.181") would be ok with a .025mm (.001") press. That said, .17mm is just .0067". Without a pretty nice lathe, chuck, and live center, taking off less than .007" would be quite tough, as the measure-over-scale could very easily account for that thickness. Even with the machinery, that's one pass on the lathe and likely hit or miss.

 

[davidbooth1991]

The generator I'm using is a Briggs and Stratton gn190 7hp and sorry fabroman it is 3/4 drive I read the manual for the one down from that so I do apologise. I'm going to ask the question while I duck behind something


Is a torque convertor and a CVT belt drive the same thing or are the slight deviations between .................please be kind. Lmao

 

[landuse]

Is a torque convertor and a CVT belt drive the same thing.................please be kind. Lmao

Pretty much the same....

 

[davidbooth1991]

Ok thanks a lot land use. I'll see if I can research them more and find a way to install.

 

[OzFab]

Technically, a torque converter is one type of CVT...

Search for "TAV2"

 

[davidbooth1991]

So I can't use the laithe and I've got a job interview Saturday for a different firm. I have got to finish the kart before I leave or at least make it pushable. The only option ive got is to use the linisher to turn my axle down and set the pillow blocks up. I know that's rough but I need it finished. Wish me luck .....

 

[davidbooth1991]

Hi guys I've been looking at cvt's online and on YouTube. I know what they do, where to put them and how they work. The only thing I can't figure out is why the housing on the variator ( the one on the left direct on the drive ) has a spline??? .... Can anyone shed some light on this and maybe give me some fitting help with the system as well. I used to have a gilera sp125 but I don't think its as easy as that. Cheers guys
Dave.

 

[davidbooth1991]

So I finally decided that with the abcesne of the laithe and with little money I've got to go extreme and tackle my axle with the linisher its rough but its done..........

 

[OzFab]

For your sake, I hope it's round & not off centre...

 

[davidbooth1991]

Thanks for tour concern fabroman. I understand its rough and if helped, shouldn't be don,e but with the job offer and not having laithe I just went for it the 700mm of 30mm bar was only seven pounds so if it slightly oval I'll just do it again. Cheers guys ordering g the blocks today.

 

[davidbooth1991]

So my pillow block bearings have just arrived from 'engineers mate' (UK). And one the bearings is not pressed in to the block square so I'll have to try and square that up. Does anybody know the best way as the block is cast and I don't think plumbing the bearing to the edge of that would be too accurate. ????
Cheers guys
Dave.

 

[mckutzy]

If they are pillowblocks, they are self aligning. That's how they get them in the housing in the first place, Twist them in.

 

[davidbooth1991]

Wow mckutzy !!!!
That's was the fastest reply ever!! I really appreciate your help. I know they just twist and stamp them in to their blocks but I don't know if these will self align as they are really stiff (maybe because they are new). But it really us quite far out. I'll post a pic. In a minute pal.

 

[davidbooth1991]

So you can see in the pics that one bearing isn't set right onto the block. The bearing turns freely in its circle but I think it just needs some persuasion via rubber mallet ????

 

[machinist@large]

So you can see in the pics that one bearing isn't set right onto the block. The bearing turns freely in its circle but I think it just needs some persuasion via rubber mallet ????

Mallet or slide it on the shaft and twist the block by hand. If you have a heat gun or hair dryer, you can heat up the top of the block to expand it slightly as well.