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Capstan winch scratch build - CAD, 3D print and cast.

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Pahaha. Now where did you think I got the idea from? ;)

Thank you :) There's just something so right about a capstan on the Series, I couldn't resist, and I love the simplicity with no brake, wiring, motor or anything to worry about. It's as much for the fun of engineering it as anything else, though.

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In case anyone is interested, I've made the project public so anyone can view it:

https://cad.onshape.com/documents/5bee2f2e199b94dc6493a74a

You don't need an account or to install any software - just click the link and it'll load the model so you can view it in 3D, scroll around and pick through how it's made. If you sign up for a free account, you can even take your own copy and play around yourself. Onshape is procedural, so the stack of operations on the left is what makes the resulting parts in the list at the bottom left. If you change something below the stack from the result, you'll see the changes propagate down to the result. It's a very, very cool engineering tool! I can highly recommend the tutorial videos too.

Enjoy!

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For the amount Shapeways will charge to print something that big - you might be better just buying a printer!

Si

Well, you weren't joking about that, were you! $2000!! :hysterical::hysterical::hysterical: Thought I'd check it out, just for a giggle. Though that's printed solid, and whole lotta plastic!! I can get it down to $350 euros by making it hollow, which is sensible, of course!

i.materialise will do in multicolour for £68, though, which is an acceptable punt, I think! It'll be great to check my work and see how it looks in the solid before going any further.

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"Take my money!?"

What's the most convenient file format to send you the model in? OnS supports export to parasolid, solidworks, STL and a few others I can't think of right now.

What material options do we have, and what's the rough cost for each?

Thank you, really do appreciate it!

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I hope your not in a rush for it!!

Material can be anything from plastic, mild steel, proper steel, cast iron, stainless steel, titanium, hastalloy, inconel or even stellite.... Its upto you...

A DXF with some simple dimensions on would be a good start.

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Not at all! It's one of those slow burn, see how it goes sort of projects. As much about learning the tools and processes as it is actually building something.

I'll bundle up a few files and send over now I've finalised dimensions. Stainless would be pretty cool, but that's a hell of a lump of steel, or a lot of machining to take chunks out of the inside. Ali might be an option.

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What about using something that's already nearly the right shape , what crossed my mind is the inner driveshaft housing (tracta joint ) off a front wheel drive 3.5t van , some are already fluted on the outside , and strong enough too I'd wager . Not only that but you could use the bearings and spline/coupling inside to the diff to hook up to the WD box.

...Having said that some lovely machining from VB would be nice too

cheers

Steveb

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That's an interesting idea. I did try to think of what I might be able to use, but didn't come up with anything. Having started the design process, I'm kinda hooked on having something that looks the part, though :)

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Indeed , and Vulcanbomber's offer to machine is hard to resist too , this is an interesting retro project for sure

cheers

Steveb

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Just noticed this thread - awesome work! Subscribed! ^_^

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Very, very nice !

Keep it coming please....

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Excellent progress sir :) Nice to see something different coming together :)

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BTW I realise plans have moved on but I have a moderately-sized electric kiln should you feel the need to cast anything ;)

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Posted (edited)

Thank you all!

Cheers @FridgeFreezer, I may take you up on that! I'd love to try some casting; having a 3D printer really takes the work out of the pattern making process and I've watched far too many Myfordboy vids. There are jet engine parts to be cast too... 

I got a few hours in the eve and managed to get the rear support structure near to completion. Had a bit of a fubar with my belt measurements. The 7KP855 is just a tad too long. I could extend out to take up the slack and get within my adjuster range, but I'm as close to the chassis as I want to be in that small space the pump is going into. I managed to get hold of a 6PK843, which may have to do as the 855mm seems the shortest 7 rib belt I can find. It's purely driving the pump, so I think the 6 rib should be OK. If not, I can get 4PK840 belts and considered carefully cutting 1 rib off and running two belts, but I'm far less convinced this is a good idea than running the 6 rib! I fully expect the clutch to give before the 6 rib belt, but time will tell. I'm consistently surprised by how strong the clutch is...

Anyway, enough of my ramblings about ribs. Have some pics:

 

71g9YHB.jpg

ZogVU4N.jpg

AsF04rk.jpg

1sjhaHr.jpg

7BzNoRb.jpg

 

Axial alignment is one rib out at the moment. The second crank pulley is very, very lightly tacked as I was expecting to have to space it somewhat. If I was defintely going with the 6 rib I'd leave it be, but I'd like to have the option of running the seven rib even if I have to run a small idler with it:

 

1Yg18eq.jpg

 

And more general views of some of the components:

 

TIMvmIi.jpg

6cKYcof.jpg

KpedGy8.jpg

Almost an "exploded" view:

 

OpIxzSM.jpg

 

I have yet to press the splined section onto the input stub and cross drill for the shear pin. 

Bonus footage of the test rig running:

 

 

Edited by lo-fi
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Is the splined adapter enough to deal with any misalignment between the shafts?

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If I can get the motor mount adapter as true as I want, it shouldn't be a problem. If not and it's looking like it's going to bind, I'll find a way of adding a flexible coupling. The splines have a tiny bit of wiggle room, but I want to get it "dead nuts on". 

I've got some 12mm steel plate to machine up to make the flanges of each end, and some 5mm wall CDS pipe to join the two flanges together. Both motor and gearbox have circular datums concentric to the input/output that I can pick up on for alignment. As long as I machine datums for the CDS pipe concentric to everything else, it should play nicely. I've found when welding this kind of contraption together that putting it in the hydraulic press and applying ~10 tons tends to nip any tendency to warp or pull right in the bud. I'll keep you posted, should be some "interesting" machining ops trying to hit both sides of the plates in one setup to maintain concentricity. Right on the limit of my little lathes capacity too. Should be fun :)

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Posted (edited)

Much progress over the weekend. One of the headache jobs was always going to be mounting the motor body to the gearbox, so no point sitting around waiting for it to make itself. I drew up a few bits in OnShape before cutting any metal. I don't have any CNC machines, but I do like making mistakes in CAD before I try making them in metal! Also useful for printing templates for drilling and cutting:

IAiKtE8l.jpg

 

The spray glue always makes them look funny, but it's enough to get some punch marks in for drilling: 

 

LRHMJmpl.jpg

 

With two sided facing ops like this, you really have to have a clear idea of what sequence to do things in. These parts are beyond my 4 jaw chuck, so everything has to be done on a the face plate. Can be a pig to get it running true again if you flip the part around, so I ended up machining a morse taper adaptor with an 18mm parallel end to re-center the parts. Sadly didn't take enough pics as usual....

It's vital to get the datums for motor, tunnel and gearbox absolutely concentric and true, or the coupling will be put under serious strain without more flexibility added. As best as I can measure, I'm within .001", which I'm rather pleased with. You can see the machined location seat for the tube here:

 

XtfPTlRl.jpg

3SuHff1l.jpg

 

The plate locates on the shoulder on the motor snugly on the other side. 

The original motor mount plate. It's aluminium (where the main body it cast iron) and rather beaten up:

 

hWyGCEql.jpg

yo0NFtPl.jpg

 

 Might as well replace it as I'm just going to machine a piece of steel anyway. More templates, punch, drill and facing work later facing work later yielded a beautiful fit:

 

j85AVacl.jpg

RybOYeTl.jpg

 

The original plate carries the oil seal and a shoulder to set the bearing pre-load:

 

oTJKY2zl.jpg

 

I can't push the oil seal in from the front because the tube will be welded to the front of the plate, so the seal has to be fitted from the back. This meant a two piece design with the shoulder being separate. Essentially, it's just a precision ring. Parts like this are hard to machine in a chuck, having critical dimensions front, back and outside. The only way to ensure this 100% is to machine those faces in one setup, so I chose to make an arbour to locate with a pre drilled hole:

 

oxAy76Ul.jpg

ePGxwBgl.jpg

 

How it began life as a piece of plate:

 

AQ0WIQGl.jpg

I took the roughing cut on the outside to see how accurate I could get it mounted on the arbour. Half a thou... that'll do me!

 

And finishing the inside. It's just for clearance, so not critical, but I had one of those rare moments with the 4 jaw, where I eyeballed it true for starters as I always do, and the dial gauge told me it was perfectly centred. Sure it'll only happen once in my lifetime!

 

1Q97LIIl.jpg

 

It's a light press fit into the plate:

 

xDYM4NDl.jpg

NlfZQvkl.jpg

 

To get the preload correct took a lot of measuring, and of course you have to take the gasket thickness into account, so I had to make that. Another CAD template:

 

l6jQRbfl.jpg

qgdHqXKl.jpg

And on she goes. Hit it spot on:

 

RybOYeTl.jpg

 

The moment of truth:

 

NqxZcg7.jpg

 

Slips together like a glove. I deliberately left the tube locating pocket in the motor plate 3 thou oversize to give me some wiggle room if I hadn't hit something bang on. Allowing the shafts to align themselves gives a consistent gap all the way around, so I'm very happy. Once i'm sure I've not forgotten anything, I'll get it all welded together. Luckily with it being such thick plate, I don't think I'll have much problem with it distorting if it's suitably clamped. Famous last words :ph34r:

The plates also need some finishing work as the edges are fresh from being cut. Then I really should paint it. I hate painting... Stay tuned!

 

Edited by lo-fi
Wrong pic
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Impressive !

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