Chieftain No 26 By Andy Musgrove

[John Clarke]

Sounds very reasonable you'll have to reveal your source. The thin strip between the mud guard and upper side armor still needs to be done. There's thirty to forty bolts there which I was going to use converted screws and nuts.
Chiefy Mctankface

[Adrian Harris]

Another option might be 10BA bolts, as these are 2.97mm AF and can be bought for £9 for 50 from ba-bolts.co.uk.

Adrian.

[andymusgrove]

Another option might be 10BA bolts, as these are 2.97mm AF and can be bought for £9 for 50 from ba-bolts.co.uk.

Adrian.

John & Adrian

The M1.6 x 3 are perfect for the hub caps but they dont supply anything other than M1.6 x 4 in thats range

be aware they dont stock many - https://www.cornwallmodelboats.co.uk/cg ... TION=Go%21

BA bolts are a good supplier and i use them a fair amount

[andymusgrove]

Another option might be 10BA bolts, as these are 2.97mm AF and can be bought for £9 for 50 from ba-bolts.co.uk.

Adrian.

John & Adrian

The M1.6 x 3 are perfect for the hub caps but they dont supply anything other than M1.6 x 4 in thats range

be aware they dont stock many - https://www.cornwallmodelboats.co.uk/cg ... TION=Go%21

BA bolts are a good supplier and i use them a fair amount

BA Bolts even sell M1.6 x 12 now. he has introduced a new mini bolt line - worth a look. https://www.ba-bolts.co.uk/methex.html

[andymusgrove]

Drive Sprocket Bolts - has anyone come up with a nice square headed bolt or nut soultion for these do we know ?

They still need to be High Tensile Bolts so limited options for these but i feel they need to have a Flat head which could be Chamfered off a bit ?

be good to know what you guys might be thinking of for these

Andy

[Adrian Harris]

I'm going to replace mine with M2.5 CSK HT bolts and 3D print the bevelled square covers for them.

Adrian.

[andymusgrove]

I'm going to replace mine with M2.5 CSK HT bolts and 3D print the bevelled square covers for them.

Adrian.

Adrian you are a genius now that is a good solution i like it - I'm just waiting for my first 3D printer to arrive as well so that will all work well

Thanks so much for sharing.

[John Clarke]

Thanks for the heads up on the BA bolts Andy I'll give them a go.

Square Stainless steel nuts can be purchased off ebay with a bit of work they don't look too bad. Richard G went the whole hog and did both sides of each sprocket. I chickened out and did only the outer side.

I did'nt bevel the nuts as I did'nt want to weaken them, with the stresses of the high track tension there's very little metal there to play with in the first place.

Don't forget to chisel out some M3 castle nuts,add studs, the wear dimple and not forgetting the grease nipple, so much joy with these sprockets I could hardly contain myself.

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[andymusgrove]

Thanks for the heads up on the BA bolts Andy I'll give them a go.

Square Stainless steel nuts can be purchased off ebay with a bit of work they don't look too bad. Richard G went the whole hog and did both sides of each sprocket. I chickened out and did only the outer side.

I did'nt bevel the nuts as I did'nt want to weaken them, with the stresses of the high track tension there's very little metal there to play with in the first place.

Don't forget to chisel out some M3 castle nuts,add studs, the wear dimple and not forgetting the grease nipple, so much joy with these sprockets I could hardly contain myself.

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Nice idea John and very much looks the part, I’m with you on doing both sides at the moment but I’ll see how the 3d printed cover nuts look, or I might use a dome head With 3d printed bolt head on top as per Adrian’s idea on the outside with the square nut inside . Thinking out loud here, I need to get in the shed with some bolts and a rule

Ok onto the sprocket hub cap. I’ve not done much on it yet but I’m going down the road that Phil Wollard laid with the bolts.

Ok ok and so I also cheated on the castle nuts too. But hey I get little enough time as it is and my ain’t that good .

I’ll have to admit it I’ve not even thought about grease nipples yet- now there’s a thought

[andymusgrove]

First of the Sprocket hub caps with bolts. Nearly ready.

M3 x 8 bolts and Castle nuts.

[andymusgrove]

Moving to the rear now and the final drive housing has a small gear that must be some sort of adjuster for the final drive



but anyhow, I searched for a gear that might do the job but nothing came to hand, so I thought I’d have a go at making one.

So out came the old school books - now called google and sussed out the required dims.

Scrap piece of ally turned down oversize by 4mm to allow the holes to be drilled into solid ally. Rather than trying to drill half a hole. So into the rotary table on the mill and drilled the holes.

[andymusgrove]

Yep looked lovely and once turned down.

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Yep looks ok but the points are all too thin and curled over a bit from the turning operation. So in the end I ask a friend to 3d print some.

And also can be seen is a 3d printed waste hatch, drawings are from Vince Cutajar who very kindly let me have a copy of the .stl file. thank you Vince - much appreciated. I think they will look a whole heap better when painted but beggars can’t be choosers.

[andymusgrove]

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And here they are fitted to the final drive housing cover

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And now awaiting Mr postman who is bringing some M1.4 nuts To complete the look.

[Stephen White]

Ah, Quill Shaft End Cap Screw, Retaining x 1. For want of a screw, the cap came off... for want of a cap, the quill shaft came out....for want of a quill shaft, the tank went round in circles....

[John Clarke]

Steven, I'm guessing it wasn't the sort of thing you'd want to happen in a built up area, although from an engineering maintenance view, it might have brought a wirery smile for a few moments. Not so funny for the driver, but since it's his job to check these sorts of things and it would be his job to explain.
Reading about son of Chieftain, Challenger 1's vibration problems would have bits fall off with regularity.
Andy, I liked the original quill end cap in metal, a clever way to do it. I modified a metal gear from the spares box, countersunk set screw for the hex center.
It's a personal choice for me to use metal parts where ever I can, (I leave the extra fine bits to Dave Dibbs which I just can't do), it's time consuming, baffling and certainly frustrating trying to keep to scale, difficult without drawings or a local vehicle. I find myself measuring off the PC screen how stupid is that