Tormach PCNC440 Bellows Protection

The Problem

It has been one of those things that has been nagging for some time….

I have had a couple of frights while severely destroying metal which were brought about by the rear Y bellows on the Tormach having got filled with swarf (chips).   The machine had tried to do a severe Y movement to the rear of the machine and the bellows began to try to crush the swarf (chips) that had accumulated in its grooves.   While it may not do any fundamental damage it does sound awful and does give rise to a transient expectation of an underwear change.

Some time ago I had ordered in some 1mm Nitrile rubber sheet to solve this problem and it had been sat gathering dust waiting a “non busy” day.   Today was that day. Time to sort this out.

The Nitrile sheet I had ordered in from EBay was 500mm square.  When cut down the middle it would nicely span the bellows.   I also had some asymmetric profile plastic angle section measuring 30mm x 20mm x 1mm which had been brought back from the Brico in France.  (For me the French Bricos are a regular source of material as their range of aluminium, steel and plastic sections far outshines our UK DIY stores).

The Method

I cut two lengths of the plastic angle at 250mm long to match the Nitrile, one for the top of the Z axis bellows and one for the table end of the Y bellows.   On the shorter arm of the each piece of plastic angle I put 5 x 3mm clearance holes and marked these though onto the rubber sheet.   I cut the matching holes in the Nitrile sheet using a rotary punch.   I put a slight countersink on the back of the holes in the plastic to reduce protrusion down into the bellows.

The Z axis mounting consists simply of two M5 clearance holes 120mm apart on the wider arm of the plastic angle.   I made these holes elongated to make adjustment of the mounting easier.

The Y axis was not so straightforward in that the two M5 bellows mounting holes into the table are set below the level of the slideway.   These are spaced at 210mm. The plastic angle had to be hacked out to allow for this but this was simple to do on my Gabro notcher as the 1mm plastic is quite soft.   Once again I made the two M5 clearance mounting holes in the plastic angle elongated for ease of adjustment.

The two pieces of plastic angle were fastened to the Nitrile using M3 x 5 countersink screws with a washer and nut facing out from the bellows.   Rather than tighten these down hard and distort the rubber I soft tightened after adding some Loctite.

Fitting the angle to the machine is a bit fiddly as I was working blind.  With hindsight the mounting holes should have been slots rather than elongated holes. This would allow the plastic angle to be slid into place without taking the bellows screws out.

The 500mm length on the Nitrile seems just about right as it does not bulk up too much at extreme table positions.  A little longer perhaps but no shorter. The 250mm width gives plenty of overlap across the bellows to keep them clear of swarf/chips.

I am pleased with the result and I am sure long term my underwear will also benefit.  Below is a guidance sketch of the plastic angle details and a few finished shots of the Nitrile in place on the Tormach PCNC440.

Bellows protection on Tormach PCNC440 using Nitrile sheet
Plastic angle dimensions for the Z and Y axis bellows Nitrile cover mounting
Full image with Nitrile sheet in place
tormach, bellows protector
Z Axis bellows protector sheet top mounting on Tormach PCNC440
tormach, bellows protector
Y Axis bellows protector sheet table end mounting on Tormach PCNC440

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Tooling Day

Each of my CNC mills has a home designed and produced tooling plate.  Both have a 25mm pitch matrix of tapped mounting holes and a further submatrix of 3.7mm tooling pin holes.   Why 3.7mm ?  So I can turn down 4mm silver steel for the tooling pins to create a retaining shoulder.

My small CNC plate has M5 tapped holes and the Tormach 440 has M8 tapped holes.   What struct me was that I has starting to create dual sets of hold down tooling, some with M5 and some with M8 mounting holes.   Not a good idea. (Entertaining and therapeutic though it might be to have ‘tooling days’).

Clearly a mounting with M8 holes was not much use with tooling having M5 mounting holes but the other way round would work if I had M8 to M5 adaptors.

As a result I have spent the day creating adaptors which you could call male and female.   Both are made from M8 hex head tensile screws with the female ones retaining the M8 head and the male ones utilising the cut off portion of thread.  I had to undercut the thread ends behind the heads so the female adaptors would sit flush.  Having undercut I then skimmed all the tops of the hex heads to be same depth.

All the turning was done with the ER25 collet chuck instead of the 3 jaw which is normally fitted to the Myford.  The male adaptor versions were a pain to turn down to M5 diameter and had to be done incrementally as the M8 threaded end could not be heavily gripped in the collet.

The female versions are quite useful if a job is being run on the Tormach that needs suspending above the table so it can machined to full stock depth.

Nothing revolutionary or original but a day well spent.

A picture explains : –

Male and female M8 to M5 adaptors

M8 to M5 adaptors in place on the Tormach tooling plate

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Microscope Update – Stand arrived

I had previously posted about the low cost HD microscope that I had bought to see if was any good.   For the price I was impressed by the microscope but not by the stand that came with it.  It only needed to be breathed on to wobble and the fixing was poor.

While browsing Amazon I spotted a more conventional looking stand for sale.  This was sold as being aluminium but when it arrived this morning this was a bit creative being mostly plastic.   However the microscope fits into the cup holder mounting and it makes a dramatic difference to the stability and therefore the usability of the microscope.   You can preset the height with a knob on the rear and then there is a rack knob to move the scope up and down.   You can focus using the microscope control or on the stand rack knob.

It is now a stable device to use and for the price of the microscope and the stand it is a useful addition to the tools available.   The stand comes with a calibration sheet to allow you get a feel for the magnification factor.   The picture below is displaying a 200um circle.

A 200um circle being displayed

 

Side view of the microscope stand

Stand link : –

https://www.amazon.co.uk/gp/product/B01HI2HYDS/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Microscope link : –

https://us.banggood.com/Wholesale-Warehouse-Mustool-G600-Digital-Portable-1-600X-3_6MP-Microscope-Continuous-Magnifier-with-4_3inch-HD-OLED-Display-wp-Usa-1119592.html?rmmds=myorder

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Microscope Addition to Assets

I often have a look on Banggood for tooling items for the workshop but the other day a low cost microscope caught my eye.   I regularly get thin slivers of brass and steel in my hands and fingers and they are a real pain to find never mind remove.   I thought for the price being asked this microscope might make a low risk purchase to help my failing eyesight.

It arrived today, looked really cheap and nasty out of the box yet I am staggered by what it does.   The screen is HD and there is a card slot for local storage.   You can record stills or video.   Have a look at the following link : –

https://us.banggood.com/Wholesale-Warehouse-Mustool-G600-Digital-Portable-1-600X-3_6MP-Microscope-Continuous-Magnifier-with-4_3inch-HD-OLED-Display-wp-Usa-1119592.html?rmmds=myorder

I will be using it for media shots on my blog that’s for sure.

Microscope set up out of the box showing part of a US 1 cent piece

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SDS Rotary Hammer Drill

Some time ago I saw an advert offering a big discount on a SDS Rotary Hammer drill from a local tool store.   I had no idea what a SDS drill was but one of my associates convinced me it was a good deal and worth getting.  Looking like a weapon out of Star Wars, it has since sat under the bench in its carrying case and never used …. until today …..

SDS Rotary Hammer Drill

I had to fasten a new garden hose to the external wall through an outer cement facing and into brick.   Normally if I can see the mortar between the bricks I cheat and fasten into the mortar.   Today however I could not see what was behind the facing cement and the hammer setting on my normal hand drill was making no impression.   Light bulb moment …. let’s try out that SDS.

The wall could have been made of cheese such was the speed that the holes were cut.  Lovely machine.  If you haven’t got one – get yourself a SDS !

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