DIY Rotisserie

[Errol62]

I can imagine the work in that. Well done.


FB ute fixer upper, EK van on rotisserie

[Blacky]

Great job , will that program give you a cut sheet with dimensions etc for fabrication??

[funkyscooter]

If only Blacky. Sketch Up Basic free and you can run it on your favorite browser so don't expect too much.

My plan is to make an 8000mm length as a guide and lay up all the pieces along it. That size is the cheapest way to purchase from my local supplier, so I might need to mix and match to see if I can get away with 1 x40 and 1 x50 length. Haven't added it up yet so might need more.

Found this recently for making the most of sheets of wood - could adapt maybe
https://cutlistoptimizer.com/

[funkyscooter]

Bit of a deep dive into my rotisserie build.
Learnt a few things too. That’s my positive spin on making mistakes.

First up, spent a lot of time in Sketch Up trying to design something that was strong, and used minimal materials. My local steel stockist sell at a reasonable price for full lengths, but as soon as you cut a length, you pay for the cut and the price per meter goes up. So was working to squeeze everything out of two lengths of 8 mtr (40 x 4 and 50 x 5). Couldn’t do it - at best I was going to have 20mm waste and that left no room for error and way too much stress. In the end settled on an additional length of 50 x 2.5 which meant I could extend the base to offer a bit more support.
The are also 8 brackets, 6 mounting plates, various bracing for the main beams, all cut from one length of 50 x 5 plate, and inner and outer steel pipe CHS with the thickest wall section. Those will have to be cuts as I only need under a metre of each

So jigged and re jigged, and came up with these final designs.

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Few tricky things to to here. Brackets are all bent so have to work out how to do that without oxy torch. All the holes are for adjustment. They work like a veriner caliper scale, so everything can be adjusted 5mm within a 140mm range. The outer pipe has 4 holes (pic shows more but realised after 4 the pattern repeats) at 0, 22.5, 45 and 67.5 degrees. Inner pipe has 6 holes all at 60 degrees. From that I should be able to spin and lock it at 15 degree increments. Do I need that level of adjustment? Probably not. Is it over kill? Hell yes! But was fun to work this out.

So placed my steel order $500 delivered (which was $110), then puzzled over if I should buy a cut off saw of hire one from Kennards. $70 to hire for a day, $210 to buy and have it delivered to my door. Decision made.

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Note the old used fire blanket as spark arrester. This is getting a lot of use when I grind things.

Steel arrives, I help the guy unload, he sees the cars and wants a look as you do. Ex panel beater. Extolling the virtues of fish oil. Unfortunately that was about all the advice he could offer up.

Sent him on his way and first lesson is discovered. Despite multiple price checks and aborted orders on the steel website, when I finally put in the order I selected the thin wall CHS pipe for the outer so the inner one is rattling around. Grrrr, re order BOTH inner and outer as I decided the inner one should be thicker as it will bear a lot of the weight.

Picked up new CHS and figured I start on the holes. Measured the diameter of the pipe, got out the calculator. Marked the six points out and wrapped my guide round the pipe ready to hole punch

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Well actually that was take two. My first attempt I drilled straight though thinking that my $100 drill press was square and my centre punch perfectly lined up. Neither were. With the additional holes drilled the final result was comical at best. My dad is and ex fitter and turner. I’m sure it would make him proud.

Decided to thread the inner pipe for an M8 bolt. Don’t want the pin coming out. This was before I realised I only need 4 holes on the outer pipe and gravity would do just as well. Way I kept the tap square…..

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Same approach and I have 4 holes in the outer.

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Fit is a bit sloppy but I think it will do.

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[funkyscooter]

2 weeks pass…

Yeah, so cut off saw. Bought it for the convenience of not having to leave home to hire one, and for the future, but despite the picture in the last post it took two weeks to ship. Should have gone to the local Total Tools and picked one up and returned the posted one. So temporarily had to store the steel. 48kg 8m lengths are not easy to move out the way. Finally….

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2 and a half back breaking hours later

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Dress all the edges with my old belt sander upside down in the vice.

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Started off with the rebate for the pipe in the upright and supporting brace. Original plan was to buy a hole saw but couldn’t work out and easy way to do the 45 angle. Plan B, back to Sketch Up, break down the model and print a 1:1 of the curves and use those as guides. Don’t have a pic of the templates, but started pretty rough with the cut off wheel in the angle grinder, then onto the powerfile to finish. Here is the start of a verticle.

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And the final fitting of a brace.

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[funkyscooter]

Next. Brackets. No heat so only solution was to cut almost through, bend and weld.

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So welding isn’t as hard as I thought….. as long as you only weld 5mm steel. Still using 6mm wire on this. Was feeding through at its highest setting.
Sweet!

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Some short time later.

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Note the propane in the background. Well I had to try and see how hot I could get the metal after I cut it. On the colour scale of heating metal, I think I achieved light brown. Of the two I tried to heat, one broke and the other tore more than the ones I bent cold.

[funkyscooter]

Time for some frames. This was the flattest surface I could find that wouldn’t burn. Need to get some metal clamps. Keep melting these ones, and they are too spongy. Used the builder square to keep things aligned. Also have a cheap engineers square, which is slightly out of square compared to the builders - conundrum!

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Chamfered (there’s a word I never thought I’d use) the edges and stripped paint around welding areas. First weld was the least successful, ended up slightly out of square and I filled it with weld before checking. Cut and re weld - this time spots in all corners and checked before filling in. With two legs on, into its new home to check square and weld in main support beam. Not quite square, rocks slightly, but hopefully a massive chunk of rotating metal will stop that. Or it will annoy the hell out of me.

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Next day, with vertical supports added.

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First test fit of vertical, with mock up of axle. Didn’t take any picks of hole drilling for the adjustment in the vertical. Again, back to sketch up and print out a bunch of templates with the correct hole spacing, centre punch into metal, drill pilot, drill 9mm for outer and 8mm for inner.

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Much fiddling and finally got things lined up in the vice.

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One crucial thing here is that the outer sleeve on the axles have to mirror each other for the rotisserie to lock at 15 degrees at both end. This photo was to remind me how to do it for the other one with the bracket bolted into the sleeve, and packed with bits of metal.

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Shazam

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Now to test that I got my mirroring right, I marked out (what I’m calling) a gusset that will be welded to the main beam for strength. Spun it round a bit and re pinned. Close enough.

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[funkyscooter]

Welding ‘gussest’ in place. Got a scrap of sheet at the back to gap it a bit as the pipe is slightly under 50mm. Tack, check and weld.

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Lining up quite nicely.

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Grab the main supports to test fit. Pretty hard to work here as I’m low on space but now would be a good time to have them side by side……. But. Oh shit! Hang on.

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What you can’t see here is the bigger picture, and my bigger stupidity. First up, the car is currently hanging over the back of the hoist by 200mm. Secondly, stands fit inside the hoist which limits their travel to 4.1 meters. Now I will remember that number for quite a while, because of all the things I measured and wrote down, the one that I failed to restrict the design to was this 4.1 metres. Think I got so caught up in minimising steel and then the unrestricted abandon of using an extra length, that my design went from practical to un usable. Measure twice, cut once. Ha!

I’m well over length. Measure car again. 3640 with taillights still on, and can be slightly less as they poke out. That gives me roughly 250mm at each end between the car and the end of the hoist.

Back….to…..Sketch…..Up.

Problem. The supports for the vertical in the original are fine on the front but foul at the rear so I spun the rear around. Problem solved, er I mean…. created. Spin back, various changes after re measuring the rear and ended up with this.

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Brackets on supports still kinda work (I hope), supports are shortened and I have to cut the legs off the base and re weld on the other end.

Over this for now, time to go and cut some rusty metal out.

[Errol62]

Wow Scott that is a major piece of work very well executed.

FB ute driver, EK van project

[Blacky]

wow - I built a rotisserie about 20 years ago out of crap that was lying around and i knocked it up in an afternoon - so THIS is how you do it properly !!

Nice work mate

[Brett027]

You certainly have some great skills Scott- Amazing design and construction.
But yes, crusty rust waits for no one
I'm thinking about some of mine now, at 3am in the #%**^% morning.

[funkyscooter]

Yes Brett, I know those mornings!
Thanks for the support guys, this is fun project to test some new skills.

[In the Shed]

Great work Scott

A few years ago I fabricated our steel deck frame from 50 x 50 x 3mm SHS and recall moving the 8m lengths, they were rather heavy. Did the same as you went and bought a metal cut off saw. Don't use it often but it is certainly handy to have and fun making lots of noise/sparks!

You certainly put some planning in your job and the results show. I see the old vice came in for a work out.

Regards
Stephen

[funkyscooter]

This is a bit of a catch up. Started welding the front together. Must have been happy with my mad welding skills. Looks strong enough.

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Then assembled it all. Spot the next mistake.

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Not going to be able to mount the subframe with this design. Again threw the tools down and back to sketchup.

Lots of swearing and cutting later......

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And a test fit with the sub frame in place

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Next cut the legs down on the base, weld the brackets to the brace supports. Originally I was just going to bolt them on, but this is a better way to go. Final test fit to prove that car and stands can fit inside the hoist.

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As there is a bit of slop in the inner and outer pipe, I added some shims made out of 1mm offcuts and tacked them in.

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[funkyscooter]

Progress on the rotisserie hit a snag with the car not lining up at the front as seen above. The car is precariously balanced on blocks over the front spring mounts at the back, something I only discovered after taking the subframe off and realised I could lift the whole car up with one hand. There is no easy way to twist the car round and slide it across. So the slightly harder way - put the diff back in. Not a one man job and my able bodied assistant has been MIA with work/uni/girlfriend/car/mates. Finally nailed him down last weekend.

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Then a bit of wiggling and shuffling and I have finally got the front bolted on. Not adjusted or balanced at this stage - just everything in its lowest position.

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The iPhone lens is a bit unkind in this picture - looks like the whole thing is twisting down. Or maybe I just wasn't standing up straight.

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Put a ratchet strap round the stand and the front of the hoist and slid the front stand/car as far forward as I could go. It's a tight squeeze up front, sub frame had to be repositioned to slide the car forward. Going to have to to a shed shuffle at some point.

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Then temporarily place the rear stand in place, ready to final measure and fabricate the rear mount.

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