Thread: Hafco SB12 - handle turning but blade not elevating

I haven't loosened any screw yet as I want understand exactly what is moving before I start fiddling. Often this is when I break things

Just to confirm terminology. Is the "Back of the Shaft" the end furthest from the winding handle?

When I fully raise the blade the shaft retracts all the way out and the space (15mm or so) between the worm gear and the spacer closes up. In the photo below you can see it fully retracts. I believe this is where it should sit. Also the rolled pin now sits outside the case of the saw.

I can also see what I believe to be a grub screw on the spacer nearest the worm gear (Is this also a collet?).

Am I right in assuming that if I tighten this grub screw - near the worm gear - I will stop the slippage? The slippage occurs on the first few winds of the handle before the blade starts dropping. I have a video of this is that helps?

I could not find a grub screw on the collet near the winding handle ... Maybe I need to keep looking.

IMG_2789 2.jpg

think about the movement you experience and where that collet is. If you tighten it to the shaft, all it's going to do is continue to move with the worm drive.

"Is the "Back of the Shaft" the end furthest from the winding handle?" yes, it's the furthest from the FRONT of the machine.

so the good news is when you have the blade full up, the space has already shrunk up in the system. That's the position that you need to lock the front collet (maybe it's a sleeve because of it's size? anyway, terminology....) against the casting. That will stop the shaft from moving the way it's going now. I would be pretty sure there is a grub screw there to hold it all together, you've just got to find it. You might need to rotate it slowly with the handle off so you have good uninterrupted view.

Mote, what you're seeing is correct. Is there a grub screw in the spacer adjacent to the worm drive gear? I'd be surprised if there is, it wouldn't do anything. The thing that limits the travel of the worm gear and shaft is the roll pin. Normally an outer sleeve that has the angle pointer integrated with it is locked on to the outer shaft and secured with a grub screw (the one in the picture I posted). You're missing the sleeve. Its contact between the end of the sleeve (pointer washer) and the roll pin that stops the worm gear and shaft being sucked into the machine. You can fix this by building up the space between the roll pin and the end of the eccentric shaft with some suitable washers.

I still suggest that you take it all apart; drive out the roll pin; loosen the nut and unscrew the eccentric shaft. This will allow you to see exactly how the mechanism works and allow you to grease and adjust it when you put it back together.

If your most recent pictures are an indication of how your saw has been put together I'm surprised that the rise and fall mechanism worked at all.

maybe there's another factor here. Perhaps the angle indicator has actually been removed, attached to the collet that it's meant to be attached to?
IMG_2782.jpg
What we need is another shot from here, when you have the slop from the other side of that casting taken up (so fully raised position). I can't recall if there was a positive spigot pointing out of mine or if there was only a flatish area to pull against, but now I think about it it seems likely that there's a large piece missing... but the good news is that a standard collet can be used in it's place. I'd have to take a photo of mine to show you, but for me there were two things at play; I needed the collet holding the shaft from pulling through like yours was, and i needed to add spacer washers to allow me to tighten the plastic handle down to get the positive height lock. Bunnings will have those if you need, they are not a specialist item.

And I'm becoming the master of the EDIT for additional clarity . Yep, as Aldav says, the sleeve that is meant to hold the pointer is AWOL. A collet from bunnings will fix it, but you may need a big bunch of washers to pack the gap, or alternatively you could get two collets and use the outer one's position to apply tension against when locking the height

So much help Poundy and Aldav I really appreciate all your time and effort.

It definitely is missing the indicator and from a diagram it does look like it is attached to a collet fo some kind.

Aldav, pulling it all apart does sound like it will give me the best result. I just don't want to get my self into more of a mess. That said, by removing the roll pin adding an extra collet or washers - I think I'll be half way to having it all apart anyway!

Thinking I will get it working first, then do the pull apart and rebuild,

So here is my plan to ensure the shaft doesn't side.

1. Raise the blade to the full height so ai can access the roll pin.
2. Drive out the roll pin ... Assuming with a pin or a pair of pliers?
3. Establish what gap needs to be filled and add either a collet or washers. (I'll check the shaft diameter with calipers)
4. Put roll pin back in.

I am assuming the Collet would be similar to this but in the correct shaft size.

Craftmaster 6.4mm Collet Router Bit To Suit 12.7mm Shaft Router

And washers would be just about ensuring I buy the right size.

Attached is the image with the Blade fully raised. The yellow circle indicates the gap that I now need to fill with a Collet or washes.

I suppose I could just go and order the Angle indicator from the supplier, but keen to keep this moving

IMG_2793.jpg

Originally Posted by mote

Craftmaster 6.4mm Collet Router Bit To Suit 12.7mm Shaft Router

That's not a roll pin, it's a router collet adaptor to adapt a 1/2" collet to accept 1/4" shaft cutters.

A role pin is this.

Doh! I meant to say Collet, sorry. I need a collet .. just not with those dimensions Editing the incorrect post now!

Originally Posted by mote

Attached is the image with the Blade fully raised. The yellow circle indicates the gap that I now need to fill with a Collet or washes.

I suppose I could just go and order the Angle indicator from the supplier, but keen to keep this moving

IMG_2793.jpg

Yes, that's where the washers need to go. That is the roll pin just at the front of your circle. From memory it's about 5/32" dia. You can get a replacement from any decent nut and bolt or engineering supplies place. As you say once you reach that point you've just about got the whole thing apart anyway.

here's my tip. Drill depth stops are almost perfect. From my saw, I think the 10mm one fitted. Haron Drill Depth Stops - 6 Pack | Bunnings Warehouse

Originally Posted by poundy

here's my tip. Drill depth stops are almost perfect. From my saw, I think the 10mm one fitted. Haron Drill Depth Stops - 6 Pack | Bunnings Warehouse

OK, wow, this is perfect

no, *almost*. Close but not perfect fit, but accessible.

Originally Posted by aldav

That is the roll pin just at the front of your circle.

Just wondering, I was planning on pulling out the roll pin with pliers. Would that work? Is it something that once removed I have to buy a new one to replace it?

The easiest way is to tap it all the way in and then drive it out with a pin punch. If it is in good condition (not bent) then you can reuse it, just tap it back in.