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What did you do Today 2018

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Neil Wyatt20/08/2018 14:20:44
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14643 forum posts
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Posted by Mick B1 on 20/08/2018 11:00:46:

Dinosaurs for the grandkids.

I used the mini-jigsaw I got from Lidl a few weeks back.

And where is the palaeontological evidence that dinosaurs had wheels?

I'm sure the grandkids will love those!

Neil

Mick B120/08/2018 15:10:41
758 forum posts
46 photos
Posted by Neil Wyatt on 20/08/2018 14:20:44:
Posted by Mick B1 on 20/08/2018 11:00:46:

Dinosaurs for the grandkids.

I used the mini-jigsaw I got from Lidl a few weeks back.

And where is the palaeontological evidence that dinosaurs had wheels?

I'm sure the grandkids will love those!

Neil

Ah well, my theory is that brass just didn't fossilise that well... laugh

Ron Laden20/08/2018 15:22:08
544 forum posts
76 photos

A couple of weeks back I got some new tyres for my old bandsaw and gave it a bit of a service. It had been stashed away in the back of a shed for the best part of 10 years and the tyres had perished and fallen apart.

Today I was cutting some parts for the 0-4-0 when it started to slow down and it eventually stopped. I thought the motor had given up, but it was the drive belt which had gone the way of the tyres and ended in bits. Luckily when I bought the tyres I also bought a spare belt which is unusual for me as I normally dont think that far ahead.

Anyway new belt fitted and I have been making sawdust most of the afternoon, I had forgotten how versatile a bandsaw can be. Its amazing how small a radius you can cut, especially if you cut a small length of radius then cut that piece away and do it in steps working your way around.

Derek Lane 220/08/2018 16:20:24
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95 forum posts
20 photos

Nothing to do with model engineering as I am still reading about it for future times when I get some machines.

But i did do some turning for a small favour for my sister who wants a footstool with a storage box so managed to get the legs turned ready to start on the box part of the storage

dscf0487 (800x597).jpg

Posted by Ron Laden on 20/08/2018 15:22:08:
 
I had forgotten how versatile a bandsaw can be. Its amazing how small a radius you can cut, especially if you cut a small length of radius then cut that piece away and do it in steps working your way around.

Have to agree a very useful tool indeed.

Edited By Derek Lane 2 on 20/08/2018 16:20:41

Alan Waddington 220/08/2018 17:38:22
344 forum posts
78 photos
Posted by Neil Wyatt on 20/08/2018 14:20:44:

And where is the palaeontological evidence that dinosaurs had wheels?

 

Well the latest scientific research suggests Tyrannosaurus had Feathers, and 'screeched' rather than 'roared" so maybe the discovery of a set of brass wheels could be just around the corner cheeky

 

Edited By Alan Waddington 2 on 20/08/2018 17:38:56

Andrew Johnston20/08/2018 21:12:45
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4142 forum posts
502 photos

I've wasted all day sitting at the computer. Someone from the TT forum has kindly sent me some pictures of the smokebox door nameplates on a fullsize Burrell SCC engine. That resulted in me binned all the CAD and CAM done so far as it was plain wrong. After a lot of faffing about, including individually selectively scaling fonts to get everything in, I had a design for the inner nameplate. And then promptly lost it all when the CAD system overwrote all the files. In the end I rang the UK agent for my CAD system for help. Many thanks to David Jupp (who I think is a member of this forum) for putting me straight on Boolean operations so I could merge an assembly into a single part, and from there to an IGS file into my CAM program. Here's the CAD model of the inner boss, all properly done with a cast iron boss and a brass inset ring with the lettering:

inner boss assembly.jpg

And the CAM toolpaths:

inner nameplate cam.jpg

The lettering needs tweaking a few thou so that the 1mm cutter can pass through all the gaps, but that should be straightforward. The task tomorrow is get the material on order.

Andrew

Neil Wyatt20/08/2018 21:22:14
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14643 forum posts
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Posted by Andrew Johnston on 20/08/2018 21:12:45:

I've wasted all day sitting at the computer. Someone from the TT forum has kindly sent me some pictures of the smokebox door nameplates on a fullsize Burrell SCC engine. That resulted in me binned all the CAD and CAM done so far as it was plain wrong. After a lot of faffing about, including individually selectively scaling fonts to get everything in, I had a design for the inner nameplate. And then promptly lost it all when the CAD system overwrote all the files. In the end I rang the UK agent for my CAD system for help. Many thanks to David Jupp (who I think is a member of this forum) for putting me straight on Boolean operations so I could merge an assembly into a single part, and from there to an IGS file into my CAM program. Here's the CAD model of the inner boss, all properly done with a cast iron boss and a brass inset ring with the lettering:

inner boss assembly.jpg

May I be cheeky?

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

Boiler Bri20/08/2018 21:42:56
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684 forum posts
272 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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4142 forum posts
502 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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125 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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4154 forum posts
171 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
3381 forum posts
664 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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11866 forum posts
518 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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125 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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11866 forum posts
518 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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288 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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11866 forum posts
518 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
130 forum posts
30 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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4142 forum posts
502 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

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