Bling for the 6 x 4 bandsaw, part 1

[bob ward]

I knocked my 6 x 4 bandsaw over a while ago and it landed on the end cap of the motor. The die cast aluminium end cap hardly looks damaged, but it distorted enough for the rotor to slightly contact the windings and for the motor to no longer work.

The motor on this import bandsaw is a .25kw/ 1/3Hp imperial pattern motor. Australia went metric nearly 40 years ago, and replacement imperial motors tend to be scarce and expensive.

My options at this stage were 1) buy a new or used imperial motor and just bolt it in, 2) buy an equivalent metric motor, remake or modify the mounting plate and pulley, or 3) buy a 180 x 40 aluminium round and make a new end cap. Option 3 won as it had the lowest capital outlay and the highest amount of fun learning opportunities.

First step was to turn the OD of the round to the correct size. I drilled a 20mm hole through the round and set a piece of 20mm cold rolled in the chuck, protruding about 25mm from the face of the chuck. Then I impaled the aluminium round on the cold rolled and pressed it against the chuck with the live centre as hard as I could. To make sure I had enough drive, I put double sided tape on the chuck jaws, an idea from one of Bog's posts I think, quite some time ago.

After turning the OD, 166mm, I faced as much of the end as I could with the same set up. This is outside end, most of it is going to be milled away before I'm done, but at this stage it provides a true surface for when I flip the piece in the jaws and start turning the inside.

I flipped the piece in the chuck, I can hold it conventionally with the outside jaws now, faced it to thickness, 38mm, and roughed out what I could of the inside. There will be a lot of rotary table work to do to finish the inside. The most important part of the project happens at this stage. First, part of the OD has to be turned down to fit into the motor housing, and once that is done, the bearing housing has to be bored. You will notice the part is marked so it goes back into the jaws in exactly the same place.

 

[bob ward]

Determining the OD of the part that slips into the motor was a bit of guess work. I couldn't get a true measurement off the old end cap as it was distorted, and the motor housing is 2mm sheet steel rolled into a not very round circle. By measuring and averaging I figured that 160mm was the size I was looking for.

And so help me, with a little tapping, the new end fits into the housing.

The end went back into the 3 jaw, and even though it went back in the same position it came from I still checked runout with a DTI. Now I could bore the bearing housing, knowing it would be concentric with the rest of the part.

The 35mm bearing in the original end cap was what I call a light tap fit, its bore measured 34.975mm (35mm less 1 thou) I finally got the new housing to 34.975mm, and again, so help me, the bearing was a light tap fit in the new housing. I was pretty impressed. I reckon I'll be splitting tenths next. No idea what that means, but I hear the big kids talk about it so it must be pretty cool.

I refitted the the end to the motor spun the rotor and everything was sweet.

The rest of the project was pretty low tech, I forgot to take photos, but it took several hours of using the rotary table and mill. I finished carving the inside first and then milled the outside.

Before and after shots

Inside

Outside

The finished assembly. The original end weighed 280gm, or 10 ounces, the replacement is a much sturdier 700gm or 25 ounces, but even so, I'll try to avoid giving it the drop test. And best of all, the motor actually runs, I have a band saw again.

 

[d.bick]

Well done Bob
Thats a neat looking job
Dave

 

[vlmarshall]

Nice work! Polish and anodize it. ;D

 

[zeeprogrammer]

Great job Bob.
Thanks for the post. Great example of what one can do.

 

[lugnut]

Wow! Bob that's a great job on the motor part.
Now I want to hear the story of how in heck did you manage to tip over your saw ???
Mel

 

[itowbig]

yeeeeeeee good deal man break it ,fix it looks good

ya how about that story of how the heck you tiped it over.

 

[New_Guy]

thats some skill you have with the rotary table

 

[dsquire]

Bob

Great Save Bob. These are the kind of stories that I like to hear. I doubt if you will ever get rid of that bamdsaw now. Even if you do, I bet you keep the motor. That deserves a karma point from me. :bow: :bow:

Cheers

Don

 

[bob ward]

yeeeeeeee good deal man break it ,fix it looks good

ya how about that story of how the heck you tiped it over.

Full confession here. http://www.homemodelenginemachinist.com/index.php?topic=7385.0

 

[itowbig]

ahh that explains it . well at least you got it fixed so yeeeeeeeee nice cart by the way

 

[BobWarfield]

That came out really nice!

Best,

BW