Dez’ workshop builds- foot powered shrinker/stretcher stand.

Well as this is retro rides, I can’t actually start the thing without backtracking and doing 3 other things first, can I? 😂

Part of my overall holistic workshop approach I’m taking this year is that if something is in the workshop, it has to pull its weight. So it has to work perfectly and be something I actually use often enough to justify.

First victim/beneficiary of that is this-


Its a hydraulic hacksaw. More specifically It’s a speedax 9”. Everyone who’s got 9 inches likes to show it off, right? Just be careful who you show it to or you’ll end up on a register.

Not sure why it’s a 9”, it must either be able to cut 9” or has a 9” stroke or something. It’ll do 4” square anyway so that’s all I really care about. For scale, the bit of blue box section in it is 50x50, so it’s a big ol’ lump.

I bought it a bit before the fire, tried it once, found a problem, every other job I needed to do was in a hurry so I didn’t get round to fixing the issues before using it properly. In the fire it just got a bit wet as it was in the unburnt corner, and it’s sat in the salvage storage area ever since.
But since I’m going to need to cut up a large amount of steel stock for this build, now would be an opportune time to sort it out.
It actually seems a fairly decent bit of kit, it’s doesn’t seem to have any discernible wear, and has a proper belt driven coolant feed setup.

It plugs in and works-ish, but the issue i’d identified was belt slip on the drive belts. I replaced the belts and it didn’t help much, but as you can see here the adjuster is maxed out.



So i decided the easiest thing to do was just cut that bit of angle off with the adjuster slots in, and let a bit of angle into it next to the back plate, so it resets the adjusters about halfway down the slots.

I took it off, stripped all the pulleys off and wire wheeled em all up and cleaned and regreased all the bearings.

Then I cut and ground the huge amount of weld off attaching the bit of angle. It looked like this has been messed around with at least twice before judging the old welds going on.


Cleaned up and location marked for the extension.


And in place. The angle was fractionally bigger than the bit on there so I just sloped the outer edges to meet up, you’ll see what I mean in a mo.


Other bit back on and ground up.


I then refitted it, did it up a bit tighter and the belts don’t seem to slip now. Not that I really got to try it properly, as the hydraulics had got loads of water in where they’d put the fire out, turning the fluid to emulsion-


Lovely. The hydraulics are odd on one of these in a couple of ways. One, it has an open hydraulic reservoir inches away from a swarf-creating blade. Hardly ideal but it seems to not effect it too much.

The other thing is the term ‘hydraulic hacksaw’ itself.
The name would suggest that the hydraulics would be in some way responsible for the cutting, wouldnt it? Well they’re not. The to-and-fro of the blade is created by nothing more exciting than an electric motor, a few pulleys and a crankshaft operating on a blade frame on a slide by means of a connecting rod.
What the hydraulics do is control the descent of the blade. If you look at the size of the counterweight above the blade, it weighs a ton. Under its own weight it just jams the blade into the workpiece way too hard, snags up and either breaks the blade or slips the pulleys.

I’m still struggling to understand exactly how the hydraulics work, but I’ve not fully stripped the valve block yet. What I think happens is this-
There is a small piston driven off a second crankshaft on the main driveshaft, that seems to pump oil into the bottom of the big piston that holds up the hacksaw arm. It has a knob with a needle valve that seems to go into the end of the smaller piston, acting as flow control. But then it’s not really a pressurised system as there is also a bypass hole on the bottom of the big cylinder that bleeds back into the reservoir. If the pump stops the arm would drop. So I guess it’s never fully capable of stopping the arm descending, it just slows it so it drops gracefully/gradually, and you can adjust that with the flow control valve.

This is the reservoir once removed from the saw and stripped down. Yes, absolutely everything is cast iron!
I’ve now got all the bits in the parts washer and will continue tomorrow once all the emulsified oil has been cleaned out.

mortcars - you need to put your name on that. I've found if you don't ask, you don't get!

On a completely unrelated note, is your avatar Ginger Wildheart?

The Wildhearts were once described as the biggest band that no-one had ever heard of!

And bringing this thread back on track, tomorrow I get the keys to my new house, and more importantly, my new single garage...