Category: Tools

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Schaublin repair of the lever operated tailstock

Since I bought this lathe, one side of the lever on the tailstock was broken. I was looking for this item for a long time – but never found it. A repair isn’t a simple task for me: it’s casted…

  • Part after sandblasting
  • Detail of the break

After milling a small recess…

  • Recess with the old, broken part
  • Milling the recess
  • Checking after milling

… I was able to pin the new steel part in place. Pinned? Yep, because of the quite intense force that this constellation has to face – I didn’t want to rely only on some steel screws.

  • Screw holes
  • Pinned on place before threading

Finally, the part is fixed by two pins and three screws. Works fine – kindly for a long time!

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Tripan tool holder

Simple but convenient – tool organisation for the tripan toolholders! This is what it looks like at the end of the day…

  • Self-made bender
  • Measuring the lenght
  • Jig – double sided
  • Cutting to lenght

The layout is set «by eye». After some weeks using it, I would change this and give some more space for «overlength» tools. Luckily some pins were used to fix the bent parts! This gets handy if you rework the layout – just change the pins.

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Bandsaw – offset blade guiding wheels

Don’t remember where I have found this one, but I liked the idea:

The blade needs to be «bent» in place mainly on two points (on the top right, and the opposite left). The concept of displacing the bearings in accordant way could preserve them a little bit. And given that this is a short task on the lathe…

 

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Bandsaw – fine adjustment on the blade guides

The idea of easing up the setup of the blade alignment is really delightful. I saw this or similar mods on different places – the one I took a in depth look onto was on the ToolsandMods website.

Mine consist of two setscrews on each side of the blade guides – this way it’s possible not only to tilt the blade, but also to displace sideways the whole block. This way it’s really easy and accurate to set the blade in two angles: in the cutting direction and also in the cutting angle of the piece beeing cut.

The parts were milled about 5.5 mm down on the sides – making space for some M5-threads and offering contact points for the setscrews. Setting this part back, some clearance for the height limiting wheel is needed. I took about 3 mm – you can see this recess in the middle of the part.

I used some vee blocks to clamp the angled parts down. Don’t worry: those angles are far away from 45°, but this doesn’t matter to the later purpose. The other parts were clamped on the precision tool vice using a ball and some brass shim stock (similar setup as you probably would use to square up stock).

Beneath the usual mess with cast iron, it turned out well. This mod is really a great simplification of the setup process. It speeds it up and makes it really more precise. I really recommend this one!

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Bandsaw – upper and lower wheels

First step: checking out, if the wheel fits the lathe 😛  This bandsaw did a great job for about two years now, and if the wheels couldn’t be trued up on the lathe, I would have kept the things as they were. As you see on the image, it worked!

Measuring the upper and lower wheels resulted in a light offset of the whole surface. Not that much, but as the wheel was on the lathe, this was a short thing to fix.

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Bandsaw – gear and pulley box

Inside the gearbox, everything looked nice: no worn gears, just a tiny amount of play. I did open this already as I received the machine. Yep, with the whole mess of oil pouring out – so if you didn’t open it yet, be prepared and have some rags on hand.

Probably this was the cause of screwing this lid that much down, that I completely thinned the gasket. Well then: a new gasket with some scrap 1 mm rubber plate is done fast – and don’t forget not to overthighten the lid. I need to confess not beeing aware of the different oils and lubrication possibilities – I believe what’s indicated on the  label. So far, it worked for me…

As I got some scrap rubber of cutting the gasket, I laid some underneath the junctions of the sheet metal box containing the belt and the pulley gears and the top of the cast iron arm. This really reduced the noise of this resonance box!

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Tripan style threading tool

Tripan Threading Tool

I really liked the idea of Jim Schmitt (on a post here) about the «inverted» retractable threading tool. Based on the concept of Charles Dolan (his post is here) it reverses the pull-handle to a push-handle – what in my opinion eases different things.

On the one hand, it’s easy to add a spring, helping to fully retract the tool completely in the right moment. On the other hand, it’s possible to let the tool clip into place by the right angle of the mechanism (and supported by the spring). This way it should be possible to cut repeatable and precise threads on the lathe.

Mechanism

The first sectional view shows the lever mechanism in neutral position.

The through hole on the left is tapped on the end and holds the spring. The two blue circles next to each other are the pins on the slider – the last one from on the lever.

In neutral position, the spring-rod pushes the carriage and the lever back. The lever is in the upper position.

 

In the activated position, the angle of the link in relation of the lever circle is slight above the center. In combination with the spring tension, this latches the setup in an safe engaged position.

Desengaging the tool needs minimal action and force – as soon as the angle drops below the center of the lever, it’s retracted by the force of the pushing spring rod.

Making

The tool is made of 1.0570 (S355J2+C, or in the USA: 1024). This is low-carbon steel and not really made for hardening (possible tough) – don’t know yet, if this tool needs to be hardened…

Most parts were milled on the Tormach PCNC440. There were tricky ones, like the dovetails, which need to be smaller than the ones of the back of the toolholder (btw.: yes, also the little version of the dovetail cutter showed on insta works like a charm), or the small cross-section for the lever, which needed a precise angle on the top as back stop. Some screenshots from the «lever side»:

Another difficult part was the axe which connects the slider to the lever: even though it’s possible to simulate almost everything in CAD/CAM, I had to make another version – 0.3 mm longer. It worked perfectly, but in the neutral position, the slider poked out a little bit 😉 

After assembly, it turned out, that two pins on the slider was overkill. One is enough – with the benefit, that a stronger ball-point-pen-spring could be used.

Plans

For those who are interested in: here are some PDF-Files of the different parts which were made:

And some photos of the working in progress:

Using the tool

First: the tool works! It’s quite sturdy and won’t move while turning the thread. Though, you really have to set up «soulful» the force of the dovetail clamp. A too high clamping may block the carriage – a too low results in sloppy toolholding!

These images were taken from my next project. An M20-something with a fine thread. That was an easy task to do with this tool.

 

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Power drawbar foot pedal mod

The power drawbar is a great add-on for the PCNC440. It eases the toolchange – which can get quite annoying the conventional way, after opening the spindle door, release the drawbar, …, tighten the drawbar and closing the case for the umpteenth time!

Yes, it’s a timesaver! But in my view, it has one drawback: the pneumatic push-button occupies one hand. And for a toolchange it’s really «handy» to have both hands available.

A foot pedal switch is a great idea. Even though there are pneumatic foot pedal switches, I didn’t wanted to hassle with long air pipes. A wire based electrical foot pedal switch is really easier to use – and to install too! The more so as there’s one in the shop I saved for later use – very simple, but sturdy, used on a punch press for years.

The bigger Tormach machines (like the PCNC770 or PCNC1100) have an electronic control circuitry for the power drawbar. Unfortunately the PCNC440 misses this option, but the needed information is on the net or can be seen on the pneumatic push-button:

  • 5 ports
  • 4 way
  • 2 positions Air Valve
  • the machine has a 48VDC- or 24VDC-output integrated (for the solenoid)

The solenoid air valve I found was an «Airtac 4V210». All in all about 20 bucks, some silencers and connectors included. Yet, the filter regulator lubricator (FRL) was set up later on – another 25 bucks investet in persistence…

The implementation was easy. The 24VDC-output (used for the water pump relais) has of course also the right values for a solenoid. The foot pedal switch was simply clipped in between.

The connector was placed between the 5-pin-connector of the height gauge/passive touch probe and the probably future expansion slot of the 4th-Axis. The toughness of the body housing is impressive by the way!

Conclusion

Besides of the power drawbar being really «handy», the footpedal activation is really fast and comfortable. You can remove the actual and insert the next tool within seconds – really a big timesaver.

Open issue and warning

Even though the footpedal is only «primed» if the machine is powered – it’s always active while it’s powered! This means, that a misstep while the spindle is turning could be fatal and dangerous. Please take precautions if you think about making such a mod – everybody is responsible for it’s own and the health of others around!

I need to dig deeper in the controller scheme – I’m quite sure, that there’s a possibility to deactivate the solenoid, while the spindle is turning…

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Gressel backward-opening workbench vice

I like old, heavy and heavily used tools! This one I found by chance:

It’s a Gressel «PS 100», 11.7 kg, backward opened by about max. 110 mm, with anvil and serrated or smooth jaws. I think this specific item is quite old. But it’s still manufactured today identically.  Even better – look a this:

True, true: they even have the 3D-model online! Oh yes. Congrats Gressel – this is really fascinating. Something that old, still produced, lifted to the 21st century – really, really great to see!

Well mine became red! In the words of rsacnc: That’s a nice red vice!

The installed jaws were replaced – even though they didn’t want to come off! On the other hand, building the new ones was an easy task – with the 3D model by hand. I made a pair of clunky, but smooth set of jaws out of scrap steel. In case that other ones would be needed I can either make some, or simply mount the additional plate (with magnets or similar).