SCM Minimax S45 Bandsaw Teardown & Overhaul

[Bill Dean]

Just to note that the belt on my S45 is an A38, but it also looks newer than the saw, so I suspect it was replaced at some point in the life of the saw, probably with the exact same experience as you.

On the spring size, mine was compressed fully for a long time, and it came in at almost exactly 60mm long, but I don't have the number of coils to hand I'm afraid.

Thanks again for this whole thread @Sideways and @deema, it is already really useful, and will definitely be in the future if anything goes wrong with my S45.

Finally, my machine doesn't have the rack and pinion rise and fall for the blade guard, and the travel isn't square to the table or parallel to the blade. Is it possible to retro-fit something like is on your version, as it looks much easier to use, and would save altering the guides every time the cut of height is adjusted?

The A 38 is the correct size. Looking at the original belt that was replaced was a bit confusing though. The new A38 shows measurements of 13mm x 1016mm. The old Optibelt-VB is 13mm x 956mm. I originally went and got an A36 belt but is was much too short. The new A38 fits perfectly. Don't know who's figuring out the conversion from inches to mm but maybe they don't know what they are doing??

 

[yetloh]

It's all academic to me but I have greatly enjoyed this thread and the obvious thoroughness and engineering expertise that has gone into theis rebuild. Thanks to you both and I hope you will do more of this sort of stuff for us all to admire and enjoy.

Jim

 

[baldkev]

It's all academic to me but I have greatly enjoyed this thread and the obvious thoroughness and engineering expertise that has gone into theis rebuild. Thanks to you both and I hope you will do more of this sort of stuff for us all to admire and enjoy.

Jim

Hi jim, deema and sideways have done quite a few rip down and rebuilds, not quite sure how you search for those specifically, but always detailed and well thought out work

 

[yetloh]

Hi jim, deema and sideways have done quite a few rip down and rebuilds, not quite sure how you search for those specifically, but always detailed and well thought out work

Tjhanks Kev. I have seen a few of them but probably not. I'll see if I can find them.

Jim

 

[Wuffles]

I've just picked up a 240v one of these and was reading through the thread and realised, mine is "missing" the lower rollers. Seems to have a couple of blocks vaguely close to the blade in the lower area, but nothing adjustable as such. Have I bought a wrong 'un or was this an optional axtra

 

[mindthatwhatouch]

I've just picked up a 240v one of these and was reading through the thread and realised, mine is "missing" the lower rollers. Seems to have a couple of blocks vaguely close to the blade in the lower area, but nothing adjustable as such. Have I bought a wrong 'un or was this an optional axtra

Sounds like its the same as mine, see my post number 79.
Just re reading this thread as I am finally getting round to sorting the bandsaw. It cuts well even in its relatively poor state.

 

[deema]

@Wuffles i suppose it depends on the age of the machine, there are at least two variants of the machine. Without pictures it’s difficult to comment.

Have a read of this
https://www.ukworkshop.co.uk/threads/bandsaw-blade-guide-theory.135481/

 

[mindthatwhatouch]

@Sideways @deema
Thanks once again for an excellent thread.
Can I ask you regarding the tensioning mechanism.
I have the 240v version (not sure if the frame is the same) need to replace/ upgrade the tensioner. Currently using the original (and probably over compressed spring) Any major disadvantages to simply changing the single spring rather than using your three?

I am missing the plastic cup and metal sleeve from my machine, I am not intent on replacing them. However it appears that the metal sleeve sits on a square washer onto of the frame, or am I looking at it incorrectly? Would your tensioner work without these, do I need to think about something on top of the frame.

 

[deema]

We chose a 3 spring solution as it was the only way we could actually achieve the spring constant necessary to tension the maximum width of blade in HSS that the machine is rated for. I approached spring manufactures and they all categorically stated that a single spring of the dimensions of the original could not be manufactured with the required spring constant. I spoke with SCM technical, and they were very evasive, they didn’t design the bandsaw and wouldn’t comment on the question of whether their spring had the required spring constant to tension the blades up to its maximum width.

The cup system is just a way of providing an indication of the blade tension. I redesigned it and made a new one for the saw we rebuilt. The original would need a new tension graphic if you change the spring. I personally wouldn’t bother and instead make a blade tension gauge and create a system to stop over compressing of the spring.

 

[simonridout]

I am setting my SMC Minimax to work, having cleaned it, especially gummed up blade guides and fitted a new blade. I am left with two problems. First, looking at the table, from the front, the right hand side is stepped down 0.50 mm compared to the left, the photo shows this. Is there any means of correcting this? Second the fence, similar to the one in this thread, is not square to the front of the table. There is no means of adjustment for this, as far as I can see

 

[deema]

Slacken off the table to allow it to tilt, adjust if necessary the stop which is just a long bolt sticking up so that the table is perpendicular to the blade.

 

[simonridout]

Deema
Thank you for your reply and your excellent restoration posts, which have been very helpful.
I probably did not explain my problem well enough.

The table and blade are perpendicular, as shown. The problem is that the table is not flat across the front edge. A 0.40 mm feeler gauge can get in, as shown in the other picture below, yet when a straight edge is put across the table, beside the blade, it is flat. This suggests, to me a slight distortion of the table,
causing the outer side of the front to sag.

 

[deema]

There should be a round pin, shaped like a hex key, ie bent with a short side. This pushes into the table where the blade slot is and keeps the two halves true to each other. Cast iron moves, if it’s been left out / not used the two sides will no longer be level. Most times you can force the pin in, and over time, something like a year, the tables will come back and little force will be required to get the pin in. They will never be true without the pin.

 

[simonridout]

Thank you. No sign of the pin. However, on further inspection, I realised that there were no bolts fixing the fence attachment bar to the table either side of the blade slot. Putting bolts into these tapped holes so that the fence attachment bar is fixed to the table at four points, reduces the step to 0.05 mm, good enough for me.

 

[Niall Church]

The top wheel assembly is simple and rugged for what it does. There are two steel channels, made from very decent wall thickness steel that are held together by a rod that is secured by a circlip on either end. The shaft for the upper wheel is bolted to this arrangement.
View attachment 127984

The two wheels are cast iron, and carry a flat tyre, rather than a crowned tyre. There are two bearings separated by a circlip at the back of each bearing. The bearings are pressed into the wheel hubs initially before being pressed into the shafts. This is one job where I believe it’s necessary to have a proper press, rather than ‘tapping’ the bearings onto the shafts.View attachment 127977View attachment 127976

The lower wheel sits on a shaft that needs to be removed for both pressing it back into the wheel, and also when ever the belt is changed. This is the only part of the design I don’t like. The hub is pulled back into the body of the saw by a bolt and large washer. The shaft and hence the wheels alignment is made by adjusting 4 bolts around the circumference of the shaft at the 12, 3, 6 and 9 o’clock positions. To remove the shaft the easiest way is to take off the pull back bolt, and then mark the shaft orientation with respect to the 4 alignment bolts. I centre punched it at 12 oclock, I then slacken two of the 4 adjuster bolts. I do this so that when I put it back the chancers are by realigning the shaft and tightening up the two bolts it will need almost no adjustmen.
Shaft and pull back bolt / washer.
View attachment 127981
The aligning bolts
View attachment 127982
The inside where the lower shaft comes throughView attachment 127983

Pressing the lower shaft back into the wheel
View attachment 127978
Lower wheel put back, note, you have to fit the belt at this stage.
View attachment 127979
Motor just poked back in and the belt out on both pulleys.
View attachment 127980

If the tyres are flat,where do you position the blade?

 

[deema]

If the tyres are flat,where do you position the blade?

You place the blade so that the gullets are just on the wheel with the teeth hanging over the edge.

 

[Niall Church]

You place the blade so that the bullets are just on the wheel with the teeth hanging over the edge.

And if it's slightly crowned?

 

[deema]

The back of the gullets should be on top of the crown, the teeth will then be over hanging and won’t damage the rubber in the wheel.

 

[AutoDoc Williams]

Hello to all, I just bought a used S45 to replace a 40 year-old 14" Delta that threw itself to its death in my driveway when one of its casters hit something as I was pushing it around in my driveway. Several things got bent and its trunnion casting broke so it was either rebuild a saw I never much liked anyway or get something with more vertical throat for resawing wider than the 6" afforded by the Delta. I found a used S45 at my favorite woodworkers' supply shop here in Southern Delaware, US and negotiated a price and it was off to the races. When I got it home and into the shop, I built a dolly for it so I could roll it around as my shop is a bit cramped. After that I started drinking and Googling and I ended up here for good photos and rebuild advice. While I had no intention of doing the complete teardown that Sideways and Deema did, I did want to check all bearings and align everything for a 3/4" blade that will be the main blade in most of my work. There were some differences between my machine and the one shown here so I wanted to put them up here in the oft chance that anyone else ends up here like I did. Look through my pics below for those differences...

Paint colors:

Upper guide ass'y:

Lower guide assy's (2 separate pieces):

Vertical arm cinch knob. No fancy rack and pinion like shown in the original writeup above:

Basically, this is either a cost-reduced version of the Sideways/Deema saw or an earlier prototype. The general difference is that any fine tuning on my saw is done by sliding stuff around by hand (or tapping with brass hammer) and cranking down setscrews, and the Sideways/Deema machine has nice verniers and rack and pinion gears and such. So far I am happy, but that can change in an instant!

Test resaw of 8" wide Ash...Good enough for me!

 

[Wuffles]

Hello to all, I just bought a used S45 to replace a 40 year-old 14" Delta that threw itself to its death in my driveway when one of its casters hit something as I was pushing it around in my driveway. Several things got bent and its trunnion casting broke so it was either rebuild a saw I never much liked anyway or get something with more vertical throat for resawing wider than the 6" afforded by the Delta. I found a used S45 at my favorite woodworkers' supply shop here in Southern Delaware, US and negotiated a price and it was off to the races. When I got it home and into the shop, I built a dolly for it so I could roll it around as my shop is a bit cramped. After that I started drinking and Googling and I ended up here for good photos and rebuild advice. While I had no intention of doing the complete teardown that Sideways and Deema did, I did want to check all bearings and align everything for a 3/4" blade that will be the main blade in most of my work. There were some differences between my machine and the one shown here so I wanted to put them up here in the oft chance that anyone else ends up here like I did. Look through my pics below for those differences...

Paint colors:
View attachment 186700

Upper guide ass'y:
View attachment 186701

Lower guide assy's (2 separate pieces):
View attachment 186702

Vertical arm cinch knob. No fancy rack and pinion like shown in the original writeup above:
View attachment 186707

Basically, this is either a cost-reduced version of the Sideways/Deema saw or an earlier prototype. The general difference is that any fine tuning on my saw is done by sliding stuff around by hand (or tapping with brass hammer) and cranking down setscrews, and the Sideways/Deema machine has nice verniers and rack and pinion gears and such. So far I am happy, but that can change in an instant!

Test resaw of 8" wide Ash...Good enough for me!
View attachment 186709

Mine wouldn't have a hope in hell of doing that resaw as the lower guides seem to be a couple of bits of plastic held in place by grub screws. Friction seems to eat them and any kind of resistance will loosen the grub screws and throw the blade offline