A Chequered Chieftain at #10

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Richard Goodwin
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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Mon Jan 20, 2020 5:21 pm

So today was the big day to assemble the bogies and I was hoping that it would all go smoothly! Alas, it was not to be :roll:

With everything painted up, the M6 plug tap finally arrived and I duly ran through the end caps to their full depth with the nett result that the screw threads of the spring shaft were now fully engaged with the end caps. A spring assembly was constructed and it was onto the first bogie. Swing arm pins were duly lubricated with Tamiya ceramic grease and the swing arms installed. The spring assembly was then positioned and the swing arm claws engaged with the slots of the spring end caps. A quick operation of the completed assembly for correct operation....bang.......the left side end cap was hitting the top of the bogie housing with over 20mm of travel remaining!
DSCF0691-1.jpg
If I forced the control arm further upwards, the claw of the spring arm was forced out of the end cap. I did try to take a picture of this but unfortunately with everything black, you can't really see anything.

Now I want the bogies to have full movement so it was time to get creative. Firstly, I rounded off the top halves of the spring assembly end caps to see if this made a difference.
DSCF0688-1.jpg
It did but not by much! So the only way forward here was to try and give them more space which meant creating a hollow at the top of the housing in which they could travel without being impeded; bye bye paint job!! :oops:

Using the existing paint, I obtained some witness marks by pushing at the control arms. This would give me an indication of where the hollow would need to be.
DSCF0692-1.jpg
A power file was then used to create the required hollow on each side. I used black primer as engineers blue to see the witness marks produced as I proceeded to create the hollows.
DSCF0693-1.jpg
Eventually, I got to the point where the spring assembly stayed engaged with the swing arm claws and I had full range of movement on both the left side...
DSCF0685-1.jpg
and the right side...
DSCF0684-1.jpg
My attempt at trying to show how deep the hollows went is I'm afraid sadly lacking......
DSCF0696-1.jpg
but your looking in the order of between 2 and 3mm. I don't think I have affected the structural strength of the bogie itself by doing this; not being a mechanical engineer, i can not say for certain. Time will tell.......either way, it looks like I've a repaint job to do :( Incidentally, I was still getting the odd tell tale mark here and there by the time I finished but this was occurring at the last few mm of travel. Bearing in mind the rubber bump stops have yet to be fitted, this I believe is ok.
DSCF0681-1.jpg

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John Clarke
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Re: A Chequered Chieftain at #10

Post by John Clarke » Mon Jan 20, 2020 8:01 pm

That's a lot of extra work going on there Richard.
I going to have to put some wheels on my bogies to see what's what, that's once I get finished on the tracks.
Love the B&D work mate, I've got two, one black and one blue, the solid ones with the step.
They always try to take a finger when I fold them up to put them away. :lol:
Oh Man, I only ride em I don't know what makes them work,
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Richard Goodwin
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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Mon Jan 20, 2020 8:11 pm

John, mines so worn and rusted, i almost get a hernia opening it out . the legs keep dropping down now when i carry it folded up; it'll get me one day for sure :shock: :lol:

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Re: A Chequered Chieftain at #10

Post by Mark Russell » Tue Jan 21, 2020 9:04 pm

Decided to do the bogie modification myself and have got 3 bogies so far with full suspension travel. Hard work even with a power file!!! 😀

Richard Goodwin
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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Tue Jan 21, 2020 9:15 pm

Nice one Mark. I took me over an hour for each one; trimming a little here and there. I've taken them apart and reassembled so many times, I can do it blindfolded :D Sound familiar?

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Re: A Chequered Chieftain at #10

Post by Mark Russell » Tue Jan 21, 2020 9:19 pm

Yes took me about an hour for each one 😩
3 left to go...
Could do it blindfolded now but it only seems right that the suspension should have full travel possible 😀

Charles A Stewart
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Re: A Chequered Chieftain at #10

Post by Charles A Stewart » Thu Jan 23, 2020 6:53 pm

:roll: Do you think a Dremel and carbide burrs might help speed up the removal process?
I haven't been in my workshop since this issue came to the fore, but will have a butchers this weekend.
Down side is i fitted suspension units last weekend,

Cheers all
Charles

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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Thu Jan 23, 2020 7:15 pm

I'm not sure Charles if i'm honest. When you use the power file, because of the width of the file and the roundness of what your trying to file, the action is in and out and side to side which gives you a reasonably smooth flowing hollow. Not sure if you could achieve that by using a Dremel although happy to be corrected!

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Re: A Chequered Chieftain at #10

Post by Charles A Stewart » Thu Jan 23, 2020 8:16 pm

True, I,ll experiment on some scrap first. Though like John I might fit wheels and push\pull chassis about a bit to, see what's the crack.
Cheers

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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Sun Feb 02, 2020 8:26 pm

Today I managed to get access to a lathe to work on the hub caps which sit on both the road wheels and the idlers in order that I can try and make the supplied hub caps look like the originals as shown below..
hubs.jpg
the supplied hub cap sits off the hub body by about 1mm and that in the centre of the original hub there is what looks like a greasing point that has a hex inner. So today, I made the hub cap sit flush with the body and created the greasing point. Here's how.....

The reason that the hub cap sits off the body is because there is a shoulder between the lip of the cap and the screw thread which you may just be able to see in the picture below...
DSCF0704-1.jpg
So in order for the cap to be flush with the body, either the hole in the body is enlarged at the top to allow the shoulder in or the shoulder is removed. I thought it was too risky to enlarge the body because there was a high potential to either damage or collapse the thread so elected instead, to remove the shoulder from the cap by creating an undercut. My weapon of choice to do this was going to be a parting off tool but even the thinnest tool available was too thick and to grind it down even further, significantly increased the risk of it breaking so instead, I ground a bevel on its right hand edge as you can see in the above picture. The tool was first gently moved towards the lip and when it just started to cut, was moved into the shoulder..
DSCF0705-1.jpg
After the cut, the end product....
DSCF0706-1.jpg
and voila...success!
DSCF0707-1.jpg
The front face of the hub cap was then trimmed level to allow the next part to sit flat against the cap....
DSCF0715-1.jpg
With the cap now sitting flush, the next step was to create the greasing point using an M3 domed screw. This is easier if you leave the hub cap screwed into the body; it's easier to centralise the body than it is the cap itself! Be careful to ensure the complete assembly is running true before starting! It takes a little juggling with the chuck but just requires a little patience.

With the assembly running true in the lathe, a centre bit was used to make a pilot hole for the screw..
DSCF0709-1.jpg
A 2.5mm tapping hole was then drilled right through the hub cap
DSCF0711-1.jpg
then tapped with an M3 tap
DSCF0713-1.jpg
and the screw inserted
DSCF0714-1.jpg
This was repeated a further 13 times.......yes I know, that's a total of 14 hub caps! But there is only 12 road wheels I hear you say and you'd be correct........but don't forget the idlers!

That completes today's action; more tomorrow when I start shaping the hub cap itself and finalising the shape of the grease point.

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Re: A Chequered Chieftain at #10

Post by Steve Ellis » Sun Feb 02, 2020 10:14 pm

Hi Richard

The hubs were filled with OEP 220 (Oil Extreme Pressure), the filler plug is like an open ended cylinder, when you unscrewed the filler plug and pulled it out, it comes out about two inches, there is a cut out section about half the depth of the cylinder and a couple of centimetres long, this is were the oil I’d poured into the hub, once it’s level with the cut out the hub is at the required level.
You then repeat for each hub.
This was the drivers responsibility.

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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Sun Feb 02, 2020 10:30 pm

Many thanks for the info Steve, I stand corrected :oops: I'll use the word lubrication next time and cover both bases just in case. :lol:

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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Mon Feb 03, 2020 7:46 pm

Today was another busy day. Following on from yesterday, today's tasks were to shape the hub cap and its lubrication point. Starting with the hub cap itself and looking at the combined picture below, the left hub is what we will start with after yesterday, the right hub is what we'll finish with.......
DSCF0719-1.jpg
Install a hub body and cap into the lathe ensuring that it is centred and running true. Adjust the slide to give a cutting angle of 45 degrees across the work....
DSCF0720-1.jpg
and slowly create the new angle....
DSCF0723-1.jpg
I stopped cutting when the screw body aligned with the line of the cone...
DSCF0724-1.jpg
Now the next two steps will have Health and Safety going loopy so I'm obliged to say don't do the them!!!

A small hand file was then used to remove the corners of the finished cut and create a smooth flowing curve..
DSCF0730-1.jpg
Final shaping of the curves and smoothing out was done with emery cloth...
DSCF0744-1.jpg
and that was the hub cap shaping finished. Now with another 13 to do, I found it easier to leave the hub body installed in the lathe and remove the cap although you may need a pair of pliers to undo it!
DSCF0746-1.jpg
Whilst I was removing the caps from the bodies, i also took the opportunity to debur the bearing holes using an oversize drill with little or no pressure applied..
DSCF0751-1.jpg
With all 14 caps completed, next up was lubrication point. First, a piece of aluminium bar was drilled and tapped for the M3 domed screw and a screw inserted....
DSCF0752-1.jpg
I decided to use this method to cut the screw head because I was concerned that the screw may lock itself in the cap and I've yet to degrease it and loctite it so it needed to be removable! The height of the screw head was then reduced to a total of 1.1mm on average; this would give a flat surface with the hex shape still showing and at the same time, would allow me to remove the screw..
DSCF0753-1.jpg
That concludes today's work and leaves only two parts remaining for the hub cap; I'm going to try and fit actual bolts to the hub cap flange and drill the two additional holes.

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John Clarke
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Re: A Chequered Chieftain at #10

Post by John Clarke » Mon Feb 03, 2020 8:41 pm

Nice work 8)
Oh Man, I only ride em I don't know what makes them work,
Definatley an Anti-Social type

Richard Goodwin
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Re: A Chequered Chieftain at #10

Post by Richard Goodwin » Mon Feb 03, 2020 9:00 pm

Thanks John. Just following your excellent example with a few minor changes :lol:

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