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View Full Version : How a 13c Grub Screw broke my Lathe



Babylon5
7th September 2009, 06:34 PM
Woke up this morning to an overcast sky, decided to head to the shed for some woodturning. I put in a block of Camphor Laurel into the lathe and began to use the roughing gouge. But something just didn't feel right.

When ever the roughing gouge went firm against the wood, the lathe slowed right down. Well I swapped the roughing gouge for the stanley screwdriver and went to investigate.

Upon casual glance it looked like one of the grub screws holding the pulley onto the motor shaft had disappeared. No big deal, I'll just drive down the road and buy another grub screw. 10 minutes and 13 cents later I was the proud owner of a new screw.

That's when things really went down hill.. :( I went to tighten up the grub screw and I had barely attempted to tighten it when the metal around where the grub screw attaches decided to fall apart.

Next was my attempt to take the pulley off the shaft. It wouldn't budge by hand so I tried to tap it with a hammer. Even more chunks decided to crumble and fall off. In the end, I was able to pull one half of the pulley off the shaft without totally destroying it.

Has anyone had previous experience with these types of Lathes? Not sure on the model as I bought it secondhand a while ago. I've attached pictures in the hope someone can recognise the model/brand etc.

Can a new pulley be bought for these lathes? Does it need to be a special one specific for my lathe or can I take it down to the tool shop and they can try to match it up the best they can? Sorry but my knowledge of pulleys is limited and I'm not sure if this pulley is rare or common.

If it needs a specific replacement pulley, would places like Carbatec be able to order it? I'll trying ringing around tommorow as most places have now closed for the day. Thanks for any info.

thefixer
7th September 2009, 06:49 PM
G'day Babylon5

Sorry to hear about your woes with the the lathe. What a PITA. But not to despair. Your Dynalink is a MC900 clone with a reeves pulley system. Spares should be readily available from Carbatec especially in Brisbane as that is their head office and warehouse.

orraloon
7th September 2009, 07:39 PM
Hare and Forbes is another place that should have them.

Enfield Guy
7th September 2009, 09:34 PM
Bummer!!!!! Hope it all works out for you.

China
7th September 2009, 09:45 PM
I realy hate muck-metal, hope you can get the new bits

Ashes
7th September 2009, 10:37 PM
Hare and forbes. Just have all the measurements you can think of. Pulley diameter, spindle diameter, pulley width at spindle, groove type. Shouldn't be a problem to replace.

artme
7th September 2009, 11:11 PM
Rotten luck mate but quite fixqable as others have said. A good chance to clean everything up and check for any other possible trouble spots.

Babylon5
8th September 2009, 12:52 PM
G'day Babylon5

Sorry to hear about your woes with the the lathe. What a PITA. But not to despair. Your Dynalink is a MC900 clone with a reeves pulley system. Spares should be readily available from Carbatec especially in Brisbane as that is their head office and warehouse.

Big thank you to Thefixer and everyone else for all the info.

I ended up calling Carbatec today and the lady that answered the phone didn't have a clue what part I needed and said she would get someone else to phone me back. In the meantime I phoned up Hare & Forbes who were actually on their game and instantly provided the part number etc.

As per usual, the parts have to come from Sydney Hare & Forbes (Brisbane is such a small town, nobody stocks anything :roll: ) and they should be arriving tomorrow.

I'll give a :2tsup: to Hare & Forbes for having a diagram available of the spare parts online to view. Only downside is that the diagram is hand drawn and to read the part numbers was very difficult. But it did make it easier to explain to the guy on the phone what part I was trying to replace.

Now just one final question. Would anyone know the correct way to reassemble the pulley once the part arrives? I know the pulley on the driveshift moves up and down the shaft depending on the rpm speed. Should the pulley on the motor shaft also move along the shaft or should that be totally secured by the grub screws?

Rum Pig
8th September 2009, 04:26 PM
I can not help with the rebuild but did you check the lower pulley? If they were made same time, same place, it may be ready to crumble as well and while you are in the mood you could replace both. just a thought even if a bit late.

Best of luck

Babylon5
8th September 2009, 04:53 PM
I can not help with the rebuild but did you check the lower pulley? If they were made same time, same place, it may be ready to crumble as well and while you are in the mood you could replace both. just a thought even if a bit late.

Best of luck

I checked the other pulley and it seems in good working condition and at $55 for a set, I'll wait and see how it all plays out. I'd rather not aggravate the Ministry of War & Finance on a replacement part for something that isn't broken.

thefixer
8th September 2009, 08:15 PM
:rolleyes:G'day Babylon5

Hope these pictures help

Pics 1 and 2 show the pulleys on the motor shaft. As you can see the left part of the pulley in fixed to the shaft and the right part slides left to right against the spring.

Pics 3 and 4 show the pulleys at the headstock and the right hand part is fixed to the drive shaft with grub screws and the left part slides left to right as you rotate the variable speed lever.

And, yes everyone, I am well aware that I need a new drive belt:rolleyes:

thefixer
8th September 2009, 08:39 PM
Also, have a look at this sites PDF. It is a "grizzley lathe" but still a mc900/mc1100 clone. At the bottom of the file is breakdown of the lathes components and a parts list.

http://grizzly.com/images/manuals/g1067z_m.pdf

Tornatus
9th September 2009, 01:23 PM
G'day Babylon5

As you have discovered the hard way, the pulleys are the real weak spot with these otherwise quite robust lathes. They are quite poor quality aluminium castings, and I don't think age has much to do with their liability to fail, although it wouldn't help. The most typical damage I have seen happens when people try to lever the pulley halves apart with a screwdriver to replace a belt ...

Before you assemble the new pulley on the shaft, take the opportunity to sand and polish any tool-marks off the inner faces of the halves - try and get a nice shiny finish with metal polish. This helps greatly with minimising belt wear and helping with smooth speed changes. If you're game to disturb it, do the same with the other pulley. And remember - lots of regular lubrication on the shafts (INOX highly recommended).

rodent
17th September 2009, 06:08 AM
PS see if there is an oiling point (looks like a ball bearing ) on the end of the motor shaft . Some have them some don't . Oil often .

Babylon5
18th September 2009, 11:27 AM
Just a quick update. Finally got the part from Sydney the other day. Strange that it was sent as "Overnight" yet it took 2 days to get from Brisbane to Sydney :?

Nearly had to place an order for another pulley as my 3 year old son decided to sit down :oo: on the good pulley that I had taken out and left on a stool. Luckily nothing cracked and after giving the shaft and pulleys a good clean and sand, I put everything back together.

What an effort to get that circlip back on to the motor shaft with that huge spring :(. Ended up getting the wife to help as trying to use the circlip pliers in one hand whilst using your other hand to hold back the spring was an exercise in frustration.

So once again, I owe a thanks to everyone for their helpful hints and tips.

P.S. If there are any Woodturners on the Northside of Brisbane that would allow me to come over and watch you to gain some tips when they are next using their lathe, I would be forever grateful.


Cheers,
Shane.

Tornatus
18th September 2009, 05:39 PM
Good to see you managed the refurbishment with no further dramas - at least now we know those pulleys can resist a 3 year-old bum!

If you keep up the regular clean and lubricate routine with this mechanism, you should remain trouble-free. Just keep an eye on the variable speed control - as soon as it shows any sign of resistance (ie takes more than one finger to shift), whip off the cover and attend to the mech.

Oh, and I hope I'm telling you something you already know when I remind you NEVER to shift the speed control unless the motor's running ....:U

Fireguard
29th September 2009, 04:38 AM
I've just had the replace the pullys on my MC900, The bearings were knacked so i replaced them but in the process i found both sets of pullys were either cracked or broken. It was probaby a good thing that you didn't try and get the motor pully from Carbatec because I ordered mine almost 2 months ago and they FINALLY came in on monday (ex Hong Kong or somewhere like that - Carbatec had none in Australia).

And to make matters worse, one of the halfs was a bit stiff puting it on.. So the old man gave me hand giving it a tap with a wooden hammer and broke the bloody thing :o:o

Hopefuly Carbatec had the sense to order a couple extras in when they got mine..

Tiger
30th September 2009, 12:52 PM
Glad everything worked out and you managed to get the pulleys. As others have said, these aluminium pulleys are very weak. Look at them the wrong way and they disintegrate, I have heard a few stories now of disintegrating and breaking off. Lubrication is vital with these machines and doing that will spare you having to be heavy-handed with the pulleys. Getting the circlip on is a PITA and others have suggested using clamps to hold the spring down although that didn't really work out for me. I have now made an access panel on the headstock so that I can lubricate quickly without having to take off the headstock cover and that helps and now gives me no excuse for not lubricating.