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What did you do Today 2018

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Boiler Bri20/08/2018 21:42:56
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806 forum posts
285 photos

I just made some new blocks for my expansion link on the brittania. I was a bit worried about having to force the fork open to get the old ones out and the new ones in. I all sprang back to where it should be so that was a bonus.

Old ones were well worn and in need of change.

B

Andrew Johnston20/08/2018 21:48:41
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4890 forum posts
550 photos
Posted by Neil Wyatt on 20/08/2018 21:22:14:

May I be cheeky?

Could you let me have an STL of that, it would be fun to do a 3D print

The complete assembly or just the nameplate ring? The whole assembly is fine, but what you can't see is that there is 3/4" boss underneath that locates in the smokebox door. For 3D printing I'd hide that otherwise most of the boss will be unsupported. Confirm what you'd like and I'll ping the STL file by email.

Andrew

David Taylor20/08/2018 23:14:12
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128 forum posts
39 photos
Wow, that's neat. What's the size and what size cutter did you use? I'm in the process of designing the inner nameplate ring for my traction engine; I'm not sure yet whether I'll use a 1/32" or 1mm endmill. One issue is how to ensure the plate is flat to start; with a 0.1mm or 0.2mm DOC flat is good! How did you deal with it? I'll be doing the machining on my Tormach.

Thanks Andrew!

The plates are 40x150mm, the engraving is 0.75mm deep. I used a pocket operations with first 4mm then 2mm end mills with 0.25mm DOC, then finished off with a profile operation using a 1.5mm endmill at full DOC. I'm happy with the result with the paint hiding most of the machining marks. I cut the brass to size first so could hold it in the vise.

As for holding stock flat, I'm stumped so far. The next job was to cut some brackets out for my new loco and I couldn't hold the 1.6mm steel flat. I just clamped it down and hoped for the best in that case. Of course that played havoc with the final profile passes, cut-through, and tabbing but I got away with it.

I've been thinking about it for a few days any can only think good quality double sided tape or the superglue trick might do it, but I haven't found any locally. A vacuum table or magnetic chuck isn't on my horizon.

I'm leery of superglue because I tried it recently in the lathe for a copper disc, and had tailstock clamping too, and it still flung out and put a hole in my new workshop wall

David.

Bazyle21/08/2018 08:46:51
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4761 forum posts
187 photos

Hooray for holidays! laugh I got to work in only an hour 'cos all the numpties who like to jam up the M25 and crash while lane weaving have gone away. Only one a-hole who had queue jumped by going down the wrong lane trying to crash into me today.

SillyOldDuffer21/08/2018 08:52:58
4784 forum posts
1011 photos
Posted by David Taylor on 20/08/2018 23:14:12:
...
...

I'm leery of superglue because I tried it recently in the lathe for a copper disc, and had tailstock clamping too, and it still flung out and put a hole in my new workshop wall

...

My experience of superglue used to hold work is that it works well about 80% of the time and I'm not sure what causes the failures. I wonder if the bond gets too hot? Superglue is also weaker in sheer than in tension, so perhaps the combination of tool pressure and temperature become too much. Bit of a mystery.

Dave

Michael Gilligan21/08/2018 09:16:07
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14134 forum posts
615 photos
Posted by SillyOldDuffer on 21/08/2018 08:52:58:

My experience of superglue used to hold work is that it works well about 80% of the time and I'm not sure what causes the failures. I wonder if the bond gets too hot?

.

I suspect that the main problem is that [most, cyanoacrylate] 'superglue' is brittle, rather than tough.

I haven't researched the market for near 30 years, but 'the way forward' with egineering adhesives was then 'toughened acrylic'.

MichaelG.

.

Edit: an alternative, for special jobs, might be this:

http://www.lakeside-products.com/html/cement.html

The No 70C product is very effective ... but priced accordingly !

Edited By Michael Gilligan on 21/08/2018 09:28:50

David Taylor21/08/2018 09:50:06
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128 forum posts
39 photos

I wonder if 5 minute epoxy might work better? Superglue does seem to be really strong in some circumstances and useless in others.

Has anyone tried double-sided tape? I can't find any that isn't thick and spongy so probably not what I'm looking for.

Michael Gilligan21/08/2018 10:08:45
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14134 forum posts
615 photos

PostScript

Anyone who has stopped 'crack propogation' in [say] a motorcyle windscreen, by drilling a small hole, should recognise the inherent logic in toughening adhesives:

**LINK**

http://icomp.ie/news/ucd-participation-at-the-adhesion-society-annual-meeting/

MichaelG.

Robin21/08/2018 10:31:18
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315 forum posts

How about good ol' shellac? You paint it on as button polish, thick as you like to both surfaces, dry it, fuse them together at around 80degC, cut your part then melt again to get it apart.

Tony Jeffree21/08/2018 10:35:42
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361 forum posts
6 photos

I've used superglue and also double sided sticky tape for work holding before now - both suffer the problem that the adhesion reduces as the part warms up, so they have to be used with care. Epoxy also softens with heat, so would suffer the same problem.

An alternative workholding adhesive often used in clock/watchmaking is shellac, but again, it softens with heat.

Michael Gilligan21/08/2018 10:49:37
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14134 forum posts
615 photos
Posted by Robin on 21/08/2018 10:31:18:

How about good ol' shellac?

.

Nothing much wrong with Shellac yes

... but it, too, may be a little brittle for some jobs.

MichaelG.

DrDave21/08/2018 12:47:18
166 forum posts
32 photos

I am tarting up the control box for my lathe. Instead of bodging something from a bit of of-the-shelf steel from Wickes, I ordered some bespoke sheets to be cut to size for me. They have just arrived so I am feeling smug.

Or I was until I realised that I have no excuse not to finish the job now. Hump!

Andrew Johnston21/08/2018 15:13:27
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4890 forum posts
550 photos

David: Thanks for the notes. I'm going to be using 16swg, about 1.5mm, CZ120 engraving brass for my nameplate. I'd thought about double sided tape, but I suspect it won't like the coolant. I plan to make a small fixture, like an inverted T-nut, to go in the machine vice and screw down to that through some sacrificial parts of the brass square.

Andrew

Ron Laden21/08/2018 15:53:27
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1424 forum posts
245 photos
Posted by David Taylor on 21/08/2018 09:50:06:

Has anyone tried double-sided tape? I can't find any that isn't thick and spongy so probably not what I'm looking for.

David, If you are looking for thin/non spongy double sided tape go to a carpet shop/supplier, thats where I have always got mine. Its usually 50mm wide, thin and as sticky as hell, well at least the roll I have is.

Ron

 

Edited By Ron Laden on 21/08/2018 15:56:30

Edited By Ron Laden on 21/08/2018 15:59:05

Neil Wyatt21/08/2018 16:24:13
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Moderator
16655 forum posts
687 photos
75 articles
Posted by Andrew Johnston on 20/08/2018 21:48:41:

The complete assembly or just the nameplate ring? The whole assembly is fine, but what you can't see is that there is 3/4" boss underneath that locates in the smokebox door. For 3D printing I'd hide that otherwise most of the boss will be unsupported. Confirm what you'd like and I'll ping the STL file by email.

Andrew

Thanks Andrew,

Just the ring/boss as shown in your picture, but if the underside is uneven, don't worry I can chop that off in Cura by 'sinking' it into the bed.

Neil

Neil Wyatt21/08/2018 16:25:44
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Moderator
16655 forum posts
687 photos
75 articles

I find copper doesn't like superglue, I don't think it adheres well to any surface tarnish, so adding a bright surface texture with fine emery might be a solution.

Neil

chris stephens21/08/2018 17:05:13
1045 forum posts
1 photos

What did I do today? Well by my estimation I took a couple years of my life by boring and sleeving the oil pump housing on a BMW boxer crankcase. Close tolerance work leads to nerve racking and palpitations, hence life shortening, it pays well but is really worth it?

I can see why some folk take to drink, even though I have done it before and should have learned by now, guess that makes me an old dog.Ho hum!

Michael Gilligan21/08/2018 20:03:42
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14134 forum posts
615 photos

Today ... found an unexpected source of useful-looking metal stock.

If you are in the vicinity of Dagfields [near Nantwich, Cheshire] ... look at Unit 211 in Building 6

**LINK** http://www.dagfields.co.uk/

He has a small but very tasty selection of non-ferrous materials; including bronze bar, and copper tube in model-boiler-making sizes.

It's the usual arrangement of 'Antiques Centre' with a single checkout for absentee sellers, but the folks on the checkout generally have telephone contact with the sellers.

MichaelG.

Michael Gilligan21/08/2018 21:01:38
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14134 forum posts
615 photos
Posted by Andrew Johnston on 21/08/2018 15:13:27:

... I'd thought about double sided tape, but I suspect it won't like the coolant.

.

That's one advantage of the Lakeside 70C 'cement' that I mentioned.

... Unfortunately I have no idea what it 'really is' by any other name.

MichaelG

Ian P21/08/2018 21:24:08
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2217 forum posts
90 photos
Posted by Andrew Johnston on 21/08/2018 15:13:27:

David: Thanks for the notes. I'm going to be using 16swg, about 1.5mm, CZ120 engraving brass for my nameplate. I'd thought about double sided tape, but I suspect it won't like the coolant. I plan to make a small fixture, like an inverted T-nut, to go in the machine vice and screw down to that through some sacrificial parts of the brass square.

Andrew

I think I would use carpet tape to fix the brass to a dead flat but larger metal plate and prevent the coolant getting to the tape run a small bead of sealant round the edge. Dead flat only matter if you are using a tapered cutter and are concerned about the line width. If coolant did get to the edge of the adhesive I think it would only be a problem if it made the adhesive swell and bend the plate.

I find the biggest problem unsticking the part after machining. Easy if you can use heat, but if you have to pry the two apart its easy to bend something. One never know until afterwards but often parts can be held in place with small pads of tape rather than covering the whole surface, and that would make separating much easier.

Ian P

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