What did you do today? (2013)

[Ian S CParticipant @iansc]

Good show, the box increases the value of these things quite a bit, they tend to get discarded when the toy goes to a child. I almost think it would be good to buy two of some toys (or would have been 40 + years ago when there were good British toys), one as a gift now, and one to save, and have later in life, Or flog off to the highest bidder.

Ian S C

[Davey JParticipant @daveyj]

This morning I picked up what I thought was to be a new photographic project and a motor for the Rapidor. Bought on a whim from an auction house having just seen one picture (how risky was that?). Turns out to be a tool cutter/grinder but of unknown origin. I certainly will not be hack/modding this one but would love to hear from any one who is able to identify the beast. There are no makers marks appart from the motor which is Czech. All threads and bearings appear to have no play and I only paid double figures. It was listed as "belt driven machine" and I paid only double figures for it, just above half way to treble figures! There are no other parts with it but I am sure these may be made. One happy bunny today

[Anonymous]

I hope it's not significant that it's sitting on the recycling wheelie bin.

Andrew

[NJHParticipant @njh]

Hi Davy

That's the STENT

( Looking unloved, abandoned and neglected I'm afraid!) Maybe a little TLC will revive it!)

Castings were available HERE  – I don't know if they are still. I have one 80% (ish!) complete ( a long term project!  which I return to from time to time)

Bit sad to see it in that state- it took hours and hours of work to make. Well worth spending some time on it now to breath some life back into it.

Regards

Norman

 

Edited By NJH on 23/11/2013 12:47:23

[Davey JParticipant @daveyj]

Andrew/Norman, please be assured this lady will not be in next weeks recycling. New home and new owner, she will be cleaned and fettled over the winter with a nice new coat of paint. I have emailed Blackgates to see if plans are still available, if not we I will see what I can do myself. I think just inserts are missing so will have a go at these. Thank you both very much for such a speedy reply, greatly appreciated

Regards

David

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Stub Mandrel on 22/11/2013 18:35:19:

Got a present from my brother- one of these, minus driver. 1960's and believe it or not it still works, romping around the garden on a single D-cell

Something I haven't seen before is a motor with three wires reversing with a single pole change over switch. Perhaps it has three brushes?

Neil

.

Neil,

It might be a split field motor

See Fig. 9-79 here

MichaelG.

[JasonBModerator @jasonb]

I got a bit more done on my Cart wheels, started by roughing out the hubs from 1" bar

Then out with the ball turner to cut the two concave sides

Followed by the convex middle

Then over to the mill for the spoke holes

Made a start on teh spokes but have come in to watch F1 qualifying

J

[Sub MandrelParticipant @submandrel]

Thanks Michael,

I didn't realise that DC motors with field windings were made so small! The high torque will be useful when your only power source is a single D-cell – especially if it's a weedy 1960's zinc-carbnon one.

Jason, looking good.

Neil

[Anonymous]

Spent most of the day fitting audio control units into electrical cabinets for a friend, for use in his local church hall which is undergoing major renovation.

But I did get time to cut the splines on the traction engine crankshafts using my home made cutter:

Regards,

Andrew

[Danny M2ZParticipant @dannym2z]

G'day.

Made a set of these : –

To hold jobs like this : –

A most productive afternoon's work

Regards from the land of the kangaroo

* Danny M *

[Michael GilliganParticipant @michaelgilligan61133]

Those do look handy, Danny

MichaelG.

[GaryMParticipant @garym]

Errr, today I over-tightened this pin chuck.

Gary

[JasonBModerator @jasonb]

Looks like its a Bin Chuck now

Made the other 18 spokes for my cart wheels, only had about 48" of 5/32 steel but found a length of 4mm chromed brass for the last few

Then made the 24 threaded nipples, hubs are now lkooking more like the real thing.

J

[_Paul_Participant @_paul_]

Chromed spokes eh these cart wheels are going to be a bit like 1800s Ross Styles lol

[GaryMParticipant @garym]

Posted by JasonB on 24/11/2013 20:26:04:

Looks like its a Bin Chuck now

J

Very good, Jason. I'm treating it as a "learning opportunity". There seem to be rather a lot of them.

Gary

[WindyParticipant @windy30762]

Building my new flash steam hydroplane hull out of ply and spruce as the 2013 model had been in the wars ( a few flying boat episodes at 120mph plus).

Thought of making it out of carbon fibre after some advice at the full size Coniston Speed Week but do not have enough information on weight saving, strength, reinforcing and attachment of various mountings plus the effect of heat on it.

Are there any suitable books on using carbon fibre composites please bear in mind there can be a great deal of heat that can weaken conventional epoxies on certain parts of this type of model.

Useful advice always welcome.

Paul

[Ian S CParticipant @iansc]

Paul, perhaps a ljning of stainless steel shim to protect the CF from direct heat, possibly mounted with an air gap between it and the CF of the hull. Ian S C

[TrickyParticipant @tricky]

Paul

In Formula 1 they use this to protect the carbon fibre but it may be OTT for you!

Richard

[Michael GilliganParticipant @michaelgilligan61133]

Carbon Fibre composites come in many variants

… The brakes on Aircraft and MotoGP brakes seem to handle the heat pretty well.

MichaelG.

[BazyleParticipant @bazyle]

Put up 30ft of shelves (almost) on Sunday but ran out of twinslot brackets. There is a Toolstation near work which is half the price of Wicks which is close to home. Screwfix is even nearer but mid price. The quality is lower but it doesn't matter in the workshop. Lucky to have all 3 in cycling range. Eventually might get all the clutter off the workshop floor so I can find those dropped screws etc.

Just to be awkward had to take the backplate off the lathe to get the bottom bracket screws in. Despite careful covering I will be dong a good clean to make sure the brick dust is gone.

So I know where I'm gong this lunchtime ….er now after my coffee.

[richardandtracyParticipant @richardandtracy]

Paul,

I used a little CF in aircraft interiors a few years ago (mostly used phenolic/glass). We didn't get it hot. The unidirectional layup at 70% by volume CF had a tensile strength of 1500 N/mm^2, compressive strength of around 600 N/mm^2. To give all round strength & damage tolerance a cloth was best, sections of crossed UD plies could come disbonded and the structure fell apart, strength for the cloth was around 500N/mm^2 (using B values, 95% confidence that 99% of samples were stronger than this). To get all round stiffness for light weight don't use a solid laminate, use a foam core or honeycomb core, a damage side ply of 0.015", and a reverse ply of 0.007", core 0.25" thick, 4 or 5 lb/cubic foot density. It's possible the damage side ply needs to be thicker for wave impact. That laminate weight with this layup should be around 0.11 lb/ft^2, with equivalent strength to 8mm ply.

When using it in an interior we used phenolic resin & found the weight was around double the minimum to give damage tolerance, but it was 20% lighter than glass fibre even though much more expensive. The relative cost of carbon has come down since then (mid 1990's).

When you use a foam/honeycomb laminate, attaching things gets interesting as the facing is too weak. You need to pot in inserts with epoxy to bond both skins together & get a connection to the shear carrying strength of the core. These can be aluminium cotton reels, tufnol blocks or plywood if thick enough. For joining panels such as bulkheads to hull, epoxy bonded mortise & tennons through the inboard skin are good, backed up with laminate angles 0.015" thick to bond the facings together.

Epoxy adhesive is not great at temperature. I got involved with insert strength testing at temperature. If 30C was relative strength of 1, then at 70C the tensile strength perpendicular to a panel on an insert was 0.57, and in shear (parallel to the panel) it was 0.25. Above 80C the strength was so variable we couldn't get an allowable strength at all. Dunking the hull under water may be needed after every run to prevent the strength being reduced too much.

How good are you at vacuum bag laminating? I suspect you'll get very good very quickly if you follow this route.

Regards,

Richard.

[john kennedy 1Participant @johnkennedy1]

Windy. Have you thought about 25mm Koawool blanket.It's reasonably cheap,very light and you can tuck it in easily.I use it in my casting furnace and the exterior shell is just warm to the touch.Just a thought ..John

[Keith LongParticipant @keithlong89920]

Windy

Suggest you run an internet search for "ceramic paper insulation, uk" – (the uk bit keeps the results nearer home). The stuff comes in thicknesses from about 1mm upwards with a working temperature of up to 1250degC so you're not likely to melt it. A couple of layers of that with a bit of an air gap incorporated (try a bit of origami to corrugate it) and your carbon fibre will stay nice and cool.

One thing with carbon fibre to bear in mind is that it is brittle, so a crash at 120mph with your boat could result in a lot of destruction. Kevlar (aramid) is much tougher and will stand the punishment better. It might be worth looking at using both materials, carbon in the less vulnerable areas and kevlar (or glass) reinforcement where it's likely to get impact damage when all hell breaks loose.

As Richard suggests above, the use of a cored laminate structure will give you a lot of stiffness for very little weight penalty, you could use balsa as the filling in the sandwich.

Good luck

Keith

[WindyParticipant @windy30762]

Thank you for the advice for the time being I will use plywood and spruce but will keep other composites in mind for future projects.

A problem that I am having with this forum now is that there is no email notifications even when the box is ticked above add posting.

Suggestions of how to correct this as other forums I have no problems with.

Paul

[Anonymous]

Cut the keyways in my traction engine crankshafts to finish them off. Here they are in place:

As seen on the left hand side I'm planning to have a go at the flywheels next, as they're a fairly simple turning exercise, as long as they don't part company with the faceplate during machining.

Regards,

Andrew

[Author]

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