Problems with Belt Drive Conversion

[library]

it just seems like it's a pain to get aligned correctly, or at least that's what I was finding. but I think my problems are mostly because I didn't get the bores centered.

You have two problems.

1) You didn't bore the centers accurately. Easy fix is to get it done on a lathe.

2) While you can make it work without flanges it's certainly the harder way to do it. Just like you can shift a manual transmission without a clutch but it's much harder. You generally put a flange on one of the two pulleys.

[cowanrg]

I'm going to re-measure the spline and see if a 24mm bushing would work. I found a 24mm, which is 0.5mm from my original measurement.

24mm METRIC KEYED H-BUSHING

[G59]

While you can make it work without flanges it's certainly the harder way to do it. Just like you can shift a manual transmission without a clutch but it's much harder. You generally put a flange on one of the two pulleys.

I agree.

Use a boring bar, and save yourself some money. handlewanker described the full procedure on how to get good results. Time consuming, but it's all up to you to prove to yourself that you can manage this, even through this small setback. Not only that, those lathe are really limited on how much you can chuck. I think 3" max?.

Which ever way you chose to go, Good luck.

[cowanrg]

oh, that's exactly what I did. I used two 123 blocks to elevate the pulleys off the table. I indicated on the bore (first mistake), and got the spindle centered over the bore. I used a rougher to get within 0.01" of the final bore and did like 4 passes with the boring bar/head to open it up. I just couldn't accurately indicate the center though.

And yes, it was very time consuming :-)

Yeah, the lathes are limited (actually looking at a used 9x19 now), but my biggest pulley is only 3", so it's not a HUGE deal.

I have someone with a lathe doing the same conversion and he's trying his hand at making pulleys. I'm going to see how he fares and then go from there.

[handlewanker]

Hi, I can sympathise with you as there are many roads that all lead to Rome etc etc.

Firstly, you have a splined shaft to mount a pulley with a plain bore on......going the grub screw route will eventually mean the grub screw destroys the spline groove you are going to "dig" into with the grub screw point.

You would be better served if you go with a plain bore in the pulley that has very close sliding fit on the OD of the splines....but it has to be a really good close sliding fit......and then put a keyway in the pulley bore the same width as the width of one spline gap and fit just one key in it.

THEN.......put a grubscrew in the pulley and screw it down on the key.

This is standard practice for securing hubs with keyway retention in the industry......the grub screw just makes sure the pulley does not slide up the spindle under the drive pressure, but as it is at the end of a drive belt this won't happen as the belt will, under tension, hold it centralised and prevent it from riding up or down.

Without the grub screw, the pulley being a sliding fit, will eventually vibrate and wear the bore out.

In most cases of plain bored pulleys with keys, the pulley is a light press fit....the key just doing the driving.

BTW......a properly fitted single groove vee belt will transmit more torque than a toothed belt which due to it's toothed structure can snap at any tooth valley........the toothed design, like gearing or chain drive, is primarily used to ensure synchronised transmission where that aspect is required.

On the subject of a lathe....my choice would be for a well used South Bend or Atlas flat belt model that will swing a 6" 3 jaw or 10" 4 jaw chuck.....about a 10" swing model with at least 30 or 40 inches between centres, and with a quick change gearbox for the screwcutting.....you'll get more bang for the buck using an older biggy than a new smaller hot from the dealers shelves foreign import that cost a whole lot more........I would think a price range of under a grand would be normal.

In any case you'll need the full compliment of screw cutting gears if it doesn't have the quick change gearbox, along with a decent 3 jaw chuck and a 4 jaw too.....the original face plate would be a very desirable item as sourcing one to make it fit is a pain.

If you only like the newness of a new lathe and can afford one, then don't be tempted to go small because it's cheaper......you vey soon outgrow a small lathe, and a good lathe is a lifetime buddy that will compliment any job you want to do.....mine is a 1930's Colchester Bantam 10"X 30"model.

LOL....I seem to remember that my journeyman, over 50 years ago, told me that a lathe is like a woman........marry in haste, repent at leisure, abuse one or the other any you'll regret it.
Ian.

[cowanrg]

You know, the whole "hold out for an atlas or south bend" is a lot like the people saying 'just buy a bridgeport'. If you've ever tried to actually buy one, you realize how difficult that really is. They are RARE, and when they do come up for sale, people want way too much for them. I've had a search on my phone that alerts me anytime a 'lathe' is for sale in a 100 mile radius. I've had that search for nearly a year. A couple Atlas lathes have come up, and a single southbend has come up in that time. The Atlas lathes have been the small Craftsman models, and have all been in pretty rough shape for over $1k. The southbend was several thousand, and massive.

What you're talking about is a unicorn. Maybe after a couple years of looking, one might come up, and I might be the lucky person that emails them first, but it's just not practical to hold out for one.

[Fastest1]

Of course that would depend on where you live. I live just outside of Houston. I see lathes and mills almost daily on CL. There was a Monarch this morning. Oh how I would like a 7700lb lathe. No room at the present time.

[cowanrg]

I'm in the Denver area and there are rarely any good mills or lathes for sale. And if there are, they are VERY pricey and/or trashed.

[recordingwhiz]

Atlas / Craftsman one in Houston's Craigslist this morning cheap $650

[cowanrg]

Lucky, there's one here that's been sitting outside, pretty rusty and needs to be assembled for $1500.

[handlewanker]

Hi, maybe I'm in a different mindset outlook.......when I wanted a Bridgeport I WANTED one and when one came available I bought it......it did help that our toolroom was downsizing and had 6 Bridgeports going out......mine was a belt driven model, quite well maintained and well used and went for $2,500 back in 1995....I later sold it to a mate who desperately wanted it and I then bought an Ajax, something like a King Rich model with an internal gearbox with feeds and rapids on all axes, Int 40 spindle etc.

They are out there.....for the right model I would crawl over broken glass on my bare knees....LOL

It's an investment thing......you grow old with it and learn all it's ways, be it a lathe, mill or whatever, that's why you think very carefully before you commit to buy, and a courier service is also part of the outlay......my KO Lee tool and cutter grinder came from Reliable tools (USA) via EBAY back in 2004, that's how committed you should get.

It does help if you know your machinery and can fix it if it needs a re-work.....but I'd draw the line at a "rusty model standing outside that needs TLC and lots of it".

The current model foreign import lathes for the home worker have all the bells and whistles you could want for around 2 grand.....they must be pretty good value for the money as you don't see dozens of them going cheap if at all.

The biggest drawback on old lathes is they all have small holes up the spindle and soft iron beds, whereas the foreign stuff all have big spindle bores and hardened beds.

If I was going to consider a lathe again, I would go for one of the current models with all the bells and whistles, something in the range of a 10 or 12 inch swing and as long a bed as you can get........and it must have a quick change screwcutting gearbox along with a quick changer tool post....that last item is a must have at all costs.

Have you tried puttying an add on the 'net indicating you are in the market for a lathe.......2 grand top limit or whatever.......photos needed before traveling etc.
Ian.

[Fastest1]

I just went thru the Denver area Craigslist. I found many lathes and mills. Some looked decent. It really depends on budget. There was a Gorton mill with a phase converter and some collets for 2500. I am almost ready to drive there for it. I miss Craigslook, where you could search all of the ads nationally. Keep looking for what you desire, it is there.

[cowanrg]

Yeah, sure, there are big things I can't fit in my garage. I've seen that gorton mill, but it's massive and I just don't have room for it, no matter the price. For a lathe, I'm looking to stay under $1000, I just want something small because I can't fit much else in my garage. I know there's better out there, I just don't have the space. Once I get a bigger shop, that's what I'll be looking at. But for now, I just want something small.

[Fastest1]

I understand. Keep your eyes open. There are deals to be found. Sometimes it might pay to call one of those old ads and see if the item sold, then offer what you want.

[handlewanker]

LOL....yes, I know how you are, been there myself.

We had 9 inch South Bend lathes in our school metalwork room back in the 50's....if you manage to score one of those type you'd be laughing.

Back in UK the most sought after hobby lathe was the Myford Super 7.........currently in OZ you can occasionally find one for just under 2 grand.
Ian.

[the_great_snag]

Anyone know where a guy can get pulleys to fit the stock X2 motor shafts? I have had zero luck trying to find 9mm bores with 5mm keyways. I could just buy a conversion kit, but what fun is that?