Thread: Disston Bandsaw Blade Sharpener

Charlie

The two pics below are from 1914 and 1917 catalogues. I have no more information than that I'm afraid.

Disston Bandsaw sharpener 1914.jpgDisston Bandsaw sharpener.jpg

Regards
Paul

PS: I will post them larger when I am on a different computer tomorrow. This computer only does thumbnails! In the meantime I think they can be enlarged by double clicking. Done.

Thanks Paul, that confirms it's complete at the very least from a quick visual look over. This looks relatively easy to get going with the parts I have. The 3 phase switch gear still has me a little stumped - hopefully there is a sparky lurking on here

Looking forward to commission this when I have a spare moment - I dare say it would get a run every 30 - 40yrs given my light hobby use of any saw!

Originally Posted by Charlie_6ft

...The 3 phase switch gear still has me a little stumped...

I'm not a sparkie but... I love this old switchgear. It just looks so much better than a bright plastic unit on an old machine. And of course it's made in Australia, whereas anything you buy today almost certainly isn't.

This one is the isolator.

Federal 320-2.jpg

"320-2" suggests 3 phase, 20amp (max.). I don't know the meaning of the "-2" - probably a version number.

It's important that these old switches are in good condition if you're going to reuse them. Can you show a picture of the internals?

This is an identical looking unit (in un-restored condition) - but I can't read the model number on the cover.

Federal 320.jpg

A great thing about these old units is they can be maintained/repaired - not that any modern sparkie would (take it out, throw it in the bin, and replace it with a bright yellow plastic unit).

I'm not familiar with the "2-speed" switch, but would be interested to see inside that one too.

Cheers, Vann.

On reflection, I think this one is a selector switch.

Federal 21300.jpg

Power comes in from the supply and is then fed to either one motor ("1") OR another motor ("2"). If that is the case, then it's superfluous - but lets see the interior and try to figure out the circuit first.

Cheers, Vann.

I love this old gear. Proper engineering goes into this type of thing. I can see how the file moves and the tooth pawl to limit the blade travel but I cant work out how the band is advanced.
It won't be two speeds. Might be reverse but not sure if you would ever need to reverse the sharpener. As Vann says, a look inside will sort it out. I love this old switchgear as well and I am a sparkie

The machine is designed to be flat-belt driven. However it's been adapted to a more modern electric drive - while still retaining the flat-belt (nice ).

As you've deduced, the motor drives the big vee pulley on the near end of the shaft.

20200316_203625_resized.jpg

The little pulley at the far end drives the machine via a flat belt. That little pulley should be aprox. twice as wide as the flat belt.

I'm not sure how familiar you are with flat belt drives - the two pulleys, side by side in this photo, are the loose and fast pulleys for the other end of the flat belt. One is loose (it goes round without doing anything). The other is fastened (hence "fast") to the driven shaft of your machine.

20200316_202959_resized.jpg

A "fork" moves the flat belt between the loose and the fast pulley. This is the fork arrangement on an old Wadkin:

Pulley.jpg Ignore the large pulley. It's the two smaller pulleys to the right that are loose & fast.

When you're not actually using the machine the belt drives the loose pulley (doing nothing). Then when you want to use the machine, you use the fork to slide this end of the belt from the loose pulley to the fast pulley. The far end of the belt trundles across the wide pulley on the other shaft. Measure the width of the two large pulleys on the machine - your flat belt should probably be 1/4" to 3/8" narrower than one pulley.

The further apart the driving and driven flat belt pulleys are, the better it will work (within reason). But that can take heaps of space. Best to mount the shaft well up a wall, or off the ceiling.

Some people hate flat belts because they're a little noisy. There was a small flat-belt driven drill press at the works where I did my apprenticeship. I grew to love the flick-flack sound as the jointer in the flat belt went over the pulleys. Very soothing .

My apologies if I'm teaching my grandmother to suck eggs.

Cheers, Vann.

OK here are some more pictures:

20200317_150544_resized.jpg

See the 1 and 2 - I can't understand why you would want a reverse as all the sharpener does is rock a triangle file backwards and forwards.

20200317_150600_resized.jpg

The switching lever isn't working well and needs to be pulled apart BUT it switches from one row of white thingies to the other white thingies. I am assuming it's just ON & OFF.

20200317_150608_resized.jpg

This is the isolator as Vann pointed out...

20200317_150345_resized.jpg

20200317_150405_resized.jpg

BTW, Vann, thanks for the information. Last night I did some Googling there looks to be a guy on eBay who sells belts and connectors:

https://www.ebay.com.au/itm/Alligator-Belt-Lacing-No-25-For-4-8mm-5-6mm-Balata-Flat-Belt-Joiner-Strip/251748973248
https://www.ebay.com.au/itm/Balata-Flat-Drive-Belting-1-3-metre-of-2-3ply-Roll-End-4-5mm-Thick-Drive-Belt/372962517071

OR even cheaper straight from China off Alibaba:

https://www.alibaba.com/product-detail/Carbon-Steel-Stainless-Steel-304-Conveyor_60381870774.html
28ozs /32ozs China Fcatory Round Edge Flat Transmission Belt - Buy Flat Belt Transmission,Round Edge Flat Transmission Belt,China Fcatory Round Edge Flat Transmission Belt Product on Alibaba.com
https://www.alibaba.com/product-deta...760747913.html

This is the belt I'll need to replace for a McPherson 32" Bandsaw.

20200317_161540_resized.jpg

20200317_161459_resized.jpg

Also there are also these two wooden wheels. It's pretty clear that the saw blade would be supported on this and aid in the rotation of the blade as it makes it's way around.

20200317_161238_resized.jpg

20200317_161248_resized.jpg

I am going to need a bigger shed - my tiny two car shed is just not going to cut it!

Cheers
Charl

Originally Posted by NCArcher

I love this old gear. Proper engineering goes into this type of thing. I can see how the file moves and the tooth pawl to limit the blade travel but I cant work out how the band is advanced.
It won't be two speeds. Might be reverse but not sure if you would ever need to reverse the sharpener. As Vann says, a look inside will sort it out. I love this old switchgear as well and I am a sparkie

The blade advances much the same way as in this video:

I subscribe to HTR but I hadn't seen that one. Ah-ha so the pawl actually advances the blade. Thanks.
The 1/2 switch still looks like a reverse. I'd need to check all the connections but you can omit it from the setup. The isolator is in really good nick. I'm not sure I would use it but if you decide to make sure it is properly earthed.

When I was an apprentice we had a switch with a lever like that for our dust extractor system and another for the thicknesser from memory.
They were Star/Delta 3 phase switches.
To start the switch would be pushed up to 1 which would be Star.
When the motor has run up to speed pull the lever down to 2 which would be Delta.
These were big old motors so I don’t know why a small motor like this would need this sort of switch.
Maybe the power supply was just adequate so this enabled a gently power surge on starting.
H.

Originally Posted by Charlie_6ft

OK here are some more pictures:

20200317_150544_resized.jpg

See the 1 and 2 - I can't understand why you would want a reverse as all the sharpener does is rock a triangle file backwards and forwards.

20200317_150600_resized.jpg

The switching lever isn't working well and needs to be pulled apart BUT it switches from one row of white thingies to the other white thingies. I am assuming it's just ON & OFF.

20200317_150608_resized.jpg

This has me puzzled. As I said before, I'm no sparkie - BUT that only switches two lines (presumably phase and neutral). So I don't see how that even fits into any 3-phase circuit? And unless there are more than 3 wires coming out of the motor I don't believe it is switched two speeds, nor reverse.

Originally Posted by Charlie_6ft

...This is the isolator as Vann pointed out...

20200317_150345_resized.jpg

20200317_150405_resized.jpg

As NCArcher says, that looks in good condition. If it was mine I'd take it apart and clean everything up.

Cheers, Vann.

Originally Posted by Vann

This has me puzzled. As I said before, I'm no sparkie - BUT that only switches two lines (presumably phase and neutral). So I don't see how that even fits into any 3-phase circuit? And unless there are more than 3 wires coming out of the motor I don't believe it is switched two speeds, nor reverse.

You reverse 3 phase by swapping two phases. Not a star/delta Henry, only two phases being switched. Do you like how the open set of contacts are still live and sit just under the metal lid? That's why I don't recommend that these type of switches be reused. I prefer to install modern components into the old shell. Much safer.

Could you make this safer by 'insulating' the inside with and old bicycle tire or rubber of some sort?