Foundry Work – Patterns

[Robert Atkinson 2Participant @robertatkinson2]

The article on foundry work mentions the dying art of pattern making.
There are several great example of pattern making in the two vehicle restoration threads below:

https://hmvf.co.uk/topic/314-ww1-dennis-truck-find/

https://hmvf.co.uk/topic/35087-ww1-peerless-lorry-restoration/

You will have to read through lots of other engineering dross excellence though. Definately not model engineering but they do have a Myford..
Seriously though these guys do amazing work. It’s hard to stop reading.

Robert.

[David George 1Participant @davidgeorge1]

I have had patterns made recently for remaking parts for Drummond lathe parts. I have also made patterns for simple pars which didnt need complex split and taper as well as shrinkage management for diferant part metals.

Fixed steady.

made by Greedale patern makers in resin CNC cut from a block

Castings made from body already excisting and two side covers from paterns I made. These are for a mod to add an extra gear which changes the handwheel rotation.

 

 

 

David

 

[Nigel Graham 2Participant @nigelgraham2]

Fine work!

I’m contemplating having a casting made for the replacement drop-bracket needed for my Denbigh H4 horizontal mill.

The pictures in Lathes.co suggest the original was a very curvaceous, bulbous thing but it needn’t be, and the back can be flat, like one half of your pattern for the steady.

So a very simple wooden or plastic pattern. Nearest foundry? Bridport Foundry, which has taken on the Stuart Models business, is only twenty miles away.

You’ve inspired me to make the pattern and take it to the Midlands show to ask on the Stuart stand, if it will be there.

(The drop-bracket that came with the elderly machine looks like something adapted for the task, certainly not original! And it’s broken on a previously-“welded” repair.)

[BazyleParticipant @bazyle]

Nigel, consider aluminium and you might be able to do it yourself or with help at a club. Just fatten it up at the lower end or look at the one for the Elliott Omnimill. Make more than one to place second one right next to the cutter.

[JasonBModerator @jasonb]

When Neil gets round to publishing it I have an article that shows taking a fag packet sketch through design, patterns and finally machining.

These days if you can use 3D CAD then our size castings are likely to suit 3D printed patterns so that opens things up to those that don’t like the brown stuff. Does need a well filled pattern with a thick surface. I’ve done it both ways with wood manually and also CNC cut and had quite  afew of my CAd designed patterns 3D printed and castings taken from those.

Finding foundries that will produce a decent casting from them is a different matter and becoming harder to find all the time.

[Nigel Graham 2Participant @nigelgraham2]

Thankyou – I don’t think finding the foundry is the hard part.

Trying to cast it myself would be. I’d need learn the whole skill and make the furnace etc! Even for aluminium. Though I could carve a functional bracket from aluminium bar, or fabricate a steel one.

My club has only a very basic workshop and no members who make their own castings, but does have one or two who use 3D printing. I’m sure they’d make a one-off pattern for me if I ask nicely and (obviously) pay for the materials and electricity.  Indeed, one demonstrated the equipment and technique to us in a Winter evening session last year.

My stumbling-block might be creating any CAD/CAM machine file. My fellow club-member used a special, printer-dedicated CAD programme on the connected lap-top. Indeed, so dedicated that he can monitor the process by smart-‘phone, even when as he said, one evening having a quick look from the restaurant where he and his wife were dining out! Most of his output appears to be plastic toys for his young children, so making a casting pattern would be simple, assuming physical machine capacity of course.

 

Anyway, I am very impressed by David’s and Jason’s work there, and by their showing us the technical possibilities.

One clear benefit of this approach is that it allows the additions made for the lathes to look “OEM”, enhancing the machines aesthetically as well as functionally – they match the factory product, look right and are right.

 

[JasonBModerator @jasonb]

You probably saw the printer’s “slicer” software in action. This is not a design program like CAD but what is used to convert an imported CAD file and turn it into something the printer understands. Much like the software that comes with an HP or Brother paper printer is specific to that and not a word processor. Some printers come with an inbuilt camera so you can watch the part being printed from your armchair or anywhere with web access.

Should not be too hard to knock up a suitable 1 sided pattern, will probably want a loose piece so that the top clamp boss can be pulled out of the sand. Alibre will add the draft as part of the extrusion of the main shape both externally and also to the two main holes. using “Scale” will add a shrinkage allowance.

 

[David George 1Participant @davidgeorge1]

I use Sutton foundry for both bronze and cast iron parts.

http://www.suttoncastings.co.uk

will do one offs and batch orders.

David

 

[duncan webster 1Participant @duncanwebster1]

<p style=”text-align: left;”>I’d fabricate that, not worth messing with patterns and casting</p>

[JasonBModerator @jasonb]

I suppose it comes down to what an individual is has to hand and is capable of. If your welding is pants then fabrication may not be the best option, if you like making swarf then cut from solid, could just be an inverted triangle with the point cut off if you like sawing

[duncan webster 1Participant @duncanwebster1]

You could get that shape, or something nearer the original, plasma cut from thick plate, just clean up the outside with an angle grinder

[Nigel Graham 2Participant @nigelgraham2]

A version of Jason’s suggestion but with squarer clamp-boss made along the top rather than across it, and machined to take a split-sleeve clamp as often used on bench-drill columns, would be simpler to cast or to fabricate.

My welding is poor – not much better than throwing molten steel vaguely at the joint and hoping some sticks – but I could probably manage a fabricated bracket.

I have worked out how to bore the bearing-hole on the mill itself (clamp the piece to an angle-plate bolted to the table, use a boring-head in the spindle), but a fundamental weakness of these small horizontal mills is the single over-arm, making aligning everything rather iffy.

[DiogenesParticipant @diogenes]

Once you have made the clamp, wouldn’t you bore the bearing hole with the clamp on the arm itself? – braced by all means, but not ‘floating’..?

[JasonBModerator @jasonb]

How would you feed the cutter or work with a setup like that?

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