Grrrrr!!!!! – A Townsend Hook kit update

How to explain how p!ssed of I am without resorting to a page of expletives may well be beyond my writing capabilities.

Try this. Imagine you are walking barefoot through the house and you stub your toe on the end of a door right between your big toe and its neighbour. It hurts like hell but as you’re hopping up and down on your good leg you land on a Lego brick. Unable to stand, over you go and, on the way, down you bang your elbow (whoever named it your funny bone deserves a flogging). When you can eventually get up, you bang your head on a shelf. Think of all the bad language that would create, (if you’re not unconscious) and you’ll be getting close.

If you can take a moment to consider the good swear that would engender, I’ll try to explain where I am at with Townsend Hook without the bad language. We left the story full of hope that we had a solution to the castings from home printed patterns. That hope has, for now, been dashed.

The responses from UK casters has varied from not replying, to answering all the questions you didn’t ask in an email whilst not answering the ones you did, lecturing about the subject but quickly revealing they’ve got the topic wrong. I suspect their stubbornness may result in their Kodak moment in the future.  Truth is the majority of them are past the first flush of youth and don’t see a need to change in their lifetime.

The hope was the Polish caster recommended by the printer manufacturer. His response to my enquiry was “I print, cast and show You result.”   This seemed positive and his website showed results from prints that were encouraging.  There followed an exchange of e-mails discussing details with annoying gaps between communications. After awhile I started to realise we were going round in circles with the same questions being asked that had previously been answered but that there was nothing to show for it.  One of the discussion points was over whether to do them in bronze instead of brass as the harder material would fill the small cavities in the moulds and be easier to handle. This question was asked on the 20th June and was replied in the affirmative and with the request to get on and cast a full set as a demo.

This would be the first time I assumed he was getting on with them (and to be honest I was distracted issues with the new website).  When I received another e-mail on the 8th July asking the same questions I discovered that this was me being optimistic.

I replied to this one again saying to use bronze, asking him to confirm that he was getting on with printing them and asking for a date when I could expect them.

I heard nothing back but had to give him a day or so to reply but late last week concluded that we were on a hiding to nothing and that a Plan C was necessary.

What does Plan C entail?

Well, actually we are probably further down the alphabet than that, but it involves redoing the CAD artwork for the castings so that they will work in a split two part mould.

With direct prints into a ceramic a casting medium you can print complex shapes with holes and fills that wouldn’t come out of a mould if the mould had to be reused but the ceramic mould is broken up each time so its not a problem.

Its a lot of extra work with some of the more complex designs. The original turret on the left has the top handle at a jaunty angle and has handles on the lower valves.

Now its all flatter and with the handles as extra items on the sprue that will need to be removed and added to the valves which will be fiddly. Basically, the part needs to be such that there is a part line as shown by the dotted line in the image below. Even with this we are taking a bit of a liberty as the nuts in the flanges will be relying on the bit of give a silicon mould has for them to release.

 

The redesign.

I couldn’t start the redesign straightaway but Sunday and Monday were set aside. Its gone seriously into day 3 now as well. Envisaging a day sat at the computer, Sunday started with a pre 10 am long bike ride so that it wasn’t all day sat on my behind.

It was probably going to be that sort of a day anyway with the cricket final on.

This was the set up at the start with some other images on show for effect. On the left hand screen is SolidWorks with CAD drawing open. In the middle is a scanned drawing with Test Match Special on in the browser behind whilst the laptop to the right had channel 4 cricket on with the sound off (when it wasn’t showing adverts).

OK, I’ll admit that no CAD got done in the last 10 overs and then the super over. It’d have been rubbish if I had done it.

As I type this late on Monday night the CAD is done and the files are uploaded to a commercial printers site and I will contact them for a price and delivery tomorrow. They are the first step in creating a revised schedule.

The response from the wax printers has resulted in another day of reworks as they apply different minimum standards for thickness and support to the casters and required more mods before they would print them.

Consequences

Some finer parts have had to be omitted, What would have been holes for wire “pipe” will just be shallow indentations. Some parts won’t be as fine as they would have been.

I am not very happy at having to announce that but the project needs to move forward.

The revised process

  • The commercially printed waxes are printed and sent to me for checking
  • I send them to the caster who casts metal in ceramic moulds made around the printed waxes and sends them to me for fettling and approval.
  • I send the fettled metal parts, which are now masters, back to the caster. He makes silicon two part moulds around them, casts multiple wax impressions of the parts, fits them together in a tree form and then pours a liquid ceramic around them and leaves it to set.  [it actually gets encouraged with vacuum and warmth].  When hard and dry its heated more to burn the wax out leaving a void in the ceramic.  Hot metal is poured in and encouraged to fill with centrifugal force. When cooled the mould is broken open and the parts cleaned.  They can then be sent to me.
  • I pack the kits and send them out.

I’ll have a better idea later in the week but a complication in it all is that this will now run into my holidays but I plan to take my fettling tools with me and have them sent to me in Wales to expedite the process.

Costs

This change of route does have a significant impact on the costings. I reckon that I can print the wax parts for a couple of quid each if that. The commercial printing company, using a different technology wants £17 just for the turret valve in the cab. One company quoted me £108 for a set of castings for a £95 quid kit!  We’re looking at over £300 quid to have the prints for the masters done commercially so I am taking quite a hit on this just to get the job done.

Actually, its more than that because of the desperate need to get this project moved on I am dual sourcing the new waxes from one source and as complete cast masters from another source.

Giving Up  –  1

I’m not really one for sharing emotions and certainly not online but I will share this with you. Working for yourself and working alone is a thankless task and the swings between highs and lows can be paralysing.

I’ll admit that when this casting issue turned to a pile of poo it was a massive low and it took a few days to get my head into a position to start sorting it out.  Getting the new website online has also piled the pressure on with a ridiculous workload to get products added that is still only partly done. Definitely burning the candle at both ends to the extent that the bit in the middle was getting very warm and squidgy.

I am back up from that massive low now and, lets be honest, there is no point trying to sort it out until your heads back in the game.

Giving Up  –  2

No, I am not giving up on the printed wax route but I will pursue it with other projects that aren’t time critical or committed. I am convinced its the way ahead and I will eventually find a caster to work with or end up with my own foundry [I hope I find someone as I don’t want a foundry]

WHAT HAPPENS NOW?

Here is the constant dilemma, do you hang on publishing something so as to include some additional detail you expect to firm up or do you publish and be damned?

I’ll be honest, when I started typing this I was only part way in to the redesign work and I was feeling pretty down about the entire thing. As I type this now with the STL files lodged with the two sources I am feeling a bit more optimistic about things.

I can see a path via either route from which we may get the first castings late August but there are a lot of variables along the way which could trip it up yet.  It may be possible to start shipping kits at the end of August but I am not offering a life dependant promise on that.

I will post further updates here as and when there is something to report. Now this is published I won’t reply to individual e-mails or phone messages wanting a personal explanation. If I did I’d never get any work done.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.