Woody's Workshop - Page 25 of 57 - Keeping the Grey Matter active

April 12, 2021September 8, 2023

Lempor Nozzle added to Poly V 5″ steam locomotive

Lempor Modification to my Poly V

This post was corrupted when converting from Classic Editor to the new Block Editor and has been re-created.

I have made mention of my Poly V 5″ gauge live steam locomotive elsewhere on my blog. With lockdown having restricted running the engine on the Club track, the loco has sat idle in the workshop.

The locomotive has always been a struggle to maintain steam over a full running day. It starts off enthusiastically but then begins to struggle. This is frustrating and also embarrassing when I have to push it round to the steaming bay.

I was sent some notes on Lempor Draughting to change the blast characteristics in the smoke box. With time on my hands I spent some time on Fusion 360 drawing up a possible Lempor assembly. This is shown below. It consists of four nozzles each having a cumulative aperture area equal to the original blast nozzle as fitted in the Poly V.

The assembly was quite tricky. I bought in a new standard nozzle from Poly and then modelled it and the new sub nozzles in Fusion 360 to create the toolpath to mill out on the CNC, The new nozzles were created on the lathe and the mating butt flats machined on them in the mill. It was very fiddly. I wired them together and silver soldered them in place. Here is a picture of the finished assembly before fitting.

Because the new blast is diverging I had to increase the height of the petticoat. I did this experimentally by fitting a small grub screw at the back of the smoke stack to grip the petticoat as I moved it up and down. This resulted in the petticoat being almost at its maximum height. One idea suggested by a club member was to make this adjustment on a cold morning with the smoke box door open so you can see the blast pattern.

My subjective conclusion is that the engine now steams from cold much quicker and it runs very well (providing I keep the fire level high in the firebox….). Whether this is the new blast pipe or the Rosebud grate or the coal or a combination of all three is difficult to judge. It is certainly a different engine and a pleasure to drive.

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April 12, 2021June 7, 2021

Burgess BK3 replacement lower blade guide

Burgess BK3 Final Modification – Lower Blade Guide

This is the final piece in my Burgess BK3 bandsaw upgrade jigsaw. Having successfully replaced the top guide with a double bearing assembly my attention turned to the lower guide. Using the same principle as the upper guide I came up with the following assembly.

Burgess BK3 bandsaw replacement lower guide assembly — Stylised Fusion 360 image of the replacement lower guide assembly on my Burgess BK3 bandsaw

This seems to work well and is straightforward to implement. The bearings are standard 1/2″ size parts from Bearing Boys. These need a small brass bush to mount them on the sliding brass blocks. The blocks need a single M3 washer to space the bearing from the block and the body.

The blade pressure roller is made from silver steel and can be heat treated to improve wear from the blade edge.

The mounting bracket arm picks up on the original M5 mounting screw concept. The bracket could be milled onto the main body as a CNC operation but the two part assembly works fine and is very rigid in operation.

Here is a set of drawings for my BK3 lower guide assembly

The link below is a complete set of notes and drawings pulled into one ZIP file to cover all the modifications I have done and separately document in my blog and other author’s notes that I have come across. I hope that helps.

Updated file link to BK3 Modifications v2

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March 21, 2021

Enclosure finally added to my Tormach PCNC440

Reduction in Sparkly Bits around the House

When I bought my Tormach PCNC440 in 2016 I included the enclosure kit in my order. On receipt I thought that fitting the enclosure would dominate the size of the workshop so I never got round to fitting it. It has sat in its shipping box since then. I have consequently shared quite a bit of my swarf (chips) with long suffering family.

After a recent (particularly heavy) CNC run I had a serious covering of swarf in the machine tray and because I had no enclosure round the mill, I had quite a lot distributed further afield (i.e. into the house). Domestic peace was becoming an issue. Time to do something about it.

Out came the enclosure kit, cobwebs dusted off and around three hours later I had the enclosure fitted. I have to say it looks good and does not overpower the workshop as I thought it would. My wife is impressed and says it looks a more professional machine and ‘if you had it why didn’t you fit it before now’ ?

My Tormach PCNC440 with its enclosure fitted — The picture above shows the enclosure mounted on my PCNC440 with the monitor in the original position before fitting the extension arm to the ISO bracket. The keyboard tray uses a domestic drawer rail mounted on the top of the standard Tormach cabinet. My recently fitted dual fogbuster system and my Hall Effect based tool height setter (yellow top) are visible.

The fitting did however create some follow up problems.

My control monitor had up to now been mounted on the side of the 440 on a standard ISO TV mount. With the enclosure fitted this meant it was ’round the side’ and difficult to get to. I debated a new long reach ISO but they are expensive. Plan B was to make something. I rummaged around in my aluminium stock and with the help of Fusion 360 came up with a seriously overengineered extension arm to add to the existing ISO mount. This would allow the monitor to move forward to be in reach at the front of the mill.

ISO bracket extension on Tormach PCNC440 — My seriously over engineered extension bracket to move the ISO mounting of the monitor more to the front of the 440

This bracket became the first CNC job to run after fitting the enclosure. I am pleased to say it was the cleanest my workshop floor had ever been after running a job.

Having fitted the new bracket and mounted the monitor, all the cables needed extending. Fortunately I had had the foresight on my original order to include the extension cable kit. As a result I only had to extend the power supply lead from the monitor 12V ‘brick’ supply.

The second issue was where to mount my ITTP probe as this had formerly mounted on the side of the 440. With help of some more Fusion design I modelled a corner mount that picked up on the enclosure fastenings.

After that first heavy machining run I noticed for the first time the slight smell of the mist coolant when opening the enclosure doors. Before the enclosure was fitted the smell must have dispersed into the general workshop air. With the enclosure fitted the air was concentrated inside the mill and I only got the smell when sticking my head inside. While it had never been a problem (as far as I can tell …) I thought I should do something about it.

Sometime ago I installed a ceiling extract duct in the workshop. This vents to the outside world via a custom roof tile. Normally the system sits with a flared cowling (made from a cut down flower pot) on the ceiling entry duct. The system normally acts as a background trickle extract. The cunning plan in the design was to use various pipe components to provide bayonet style connection pins (Nylon screws) to allow extension trunking to be used. A bit like a BNC RF connector if this is familiar to you. This would allow me to use an add-on length of expanding flexi trunking to bring the extract nearer to any heavy fumy activity such as welding or oil bath hardening.

With the use of further scrap odds and ends of aluminium, I mounted a pair of support bars across the top of the new 440 enclosure. These would fix the ducting over the enclosure during heaving CNC sessions. Not a total solution but certainly one that will reduce the general smell of XtremeCut 250C when I stick my head in the enclosure.

Workshop extract system — Extract system showing ceiling mounting intake, trunking adapter and mounting on my Tormach PCNC440. Note the two Nylon screw protrusions are for a bench mounting clamp when used for welding extraction etc and now used on this new use of the system on the mill.

A good day’s activity with all the issues addressed and domestic bliss hopefully restored.

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March 4, 2021March 4, 2021

A church clock problem and lockdown timekeeping

Keeping the village clock going

From previous posts you will be aware that I am regarded as ‘Tech Support’ for the local church clock. The clock is a Cooke of York design dated from 1869. It has been running very well over the past months until a few days ago when ….twang … one strand of the strike wire rope gave way and twirled back up the rope and got wedged in the strike mechanism. The going train continued to keep time and display on the dials but no bell strikes. An eerie silence fell over the village.

Strike chain drum showing the errant strand in the barrel wheel and also the soft eye fastening onto the strike barrel. The going train barrel can be seen in the background.

The errant stand of wire was easily cleared but on further inspection the strike weight rope looked to be in a dangerous condition. I resolved to replace the rope and while doing this I would also replace the cable on the going train.

The strike chain had jammed with the weight almost at the top so this needed to be gently let down to floor level.

Strike train weight stopped almost at full wind and needed to be lowered before any work could start on replacing the cable.

New fibre cored 6 x 19 galvanised wire rope was ordered. The strike train had 6mm diameter and the going train 5mm and both needed around 30m of cable. The chosen supplier was RAMS Lifting Gear in London and they agreed to put a 20mm diameter soft loop at one end of each cable. This would loop over a button on each of the two barrels to anchor the cable. RAMS delivered the cables very quickly.

Given the social distancing restrictions in place, my normal assistants were not available to help. Instead I persuaded my wife to climb the bell tower with me to assist with the cable changes. It is a bit intimidating to ascend up the two ladders for the first time but she overcame her nerves and after a few up and downs became quite at home with the surroundings.

The new cables were unreeled and laid out down the stairs from the tower into the church so they could take their own path and not twist. We had decided to use the existing cables to pull through the new ones. This meant the soft loops and the associated crimps had to be pulled through each pulley. This was tight on a couple of them but we managed.

With the cables pulled through and into the clock cabinet we then pulled off the old cable from the drums and ran on the new ones. Inspecting the old cables revealed that they were not in the best condition and could have been an accident waiting to happen had they snapped clean through. There is no clock record to indicate when they were last changed.

The clock was soon up and running with its new shiny cables and normality was restored in the village and surrounds.

We received a number of appreciative comments from the villagers for getting the clock up and running again so quickly. Considering these comments suggested that perhaps the chimes of the clock had taken on a new meaning in COVID lockdown. Time precision had recalibrated. Watches and clocks in and around the home had ceased to be the reference in the slow world of lockdown. Nowhere to go or to be, meant watches lay on bedside tables unworn and unwanted. Instead people had moved from watching minutes to referencing life by hours. The village clock now subconsciously marked the passage of time with its hourly chimes. Everything in between had become a slowed down lifestyle. When to come or go into the garden or to the shops, when to think about a meal – all now seemed more likely to be triggered by the hourly chimes of the village clock.

Which is probably how life was in 1869 when the clock first broadcast its notes over the village.

Did we perhaps lose something somewhere along the way ?

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February 25, 2021February 26, 2021

Update on CNC milling printed circuit boards on a homemade vacuum table

Update to the use of FlatCAM to mill PCBs

There are quite a few entries on my blog regarding using FlatCAM to convert PCB design software manufacturing files into CNC code. I also have mentioned my small home made vacuum table and a floating foot compression device both for holding the PCB blank flat while the milling takes place.

I have revised my original write up to focus on FlatCAM version 8.991 and also pulled together notes on these other techniques. If you like it let me know. If there are mistakes also let me know.

FlatCAM and milling pcbs updated notes 2021

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