Tamiya 56004 King Tiger help

[qatmix 794]

Hi All, 

I am new to tanks, and have picked up an old Tamiya King tiger. It is the original one with the clutch.  I have fired it up and there are a couple of pressing issues.

One of the bevel gears has sawtoothed. - When  go forward the right hand side skips as the bevel on the gear (Attached) has worn funny, so it trys to lift itself out. In reverse it is fine (As the saw-tooth on the bevel is only one direction).  Is there anywhere that has these gears as a spare?

The second issue is that the clutch does not seem to work, moving the arm to the left and the right does not stop the track. It does however slow the whole tank down.. Any tips?

Third issue (I know I said two earlier) Is that the front sprocket wheel is coming loose. I know it is attached to the axle via a screw, but I cannot get to it as the screw is covered up under a glued in place wheel cap. (As per  the instructions). How can I remove that without damaging the small gear cap?

Help!

 

[MadInventor 3884]

In answer to your questions:

1. No. You're out of luck. As far as know none of the gearbox components are available as spares. You can however make sure there is minimal movement by making sure the grub screw is tight on in the end of the one gear shaft (Just to the left of your red arrow), and the other sleeve on the right of the photo also has a tight grub screw. PS That pin you've pulled out looks broken to me. Might be worth comparing against the one on the other side.

2. The clutch is probably disengaging, but the servo movement is not enough to put pressure on the side brakes. What side brakes I hear you ask ? The shafts that run from the front of the gearbox to the rear have fibre washers on them, at the end closest to the motor end bell. When the servo pushes on the clutch, this pushes on the shaft which should push the sleeve on the shaft onto the fibre washer, acting as a small brake.

3. Again, you can't. the only way to tighten the screw is to gouge out the plug. However I think I might have some spare ones in the loft. Give me a few days and bug me a bout it and I'll see if I can find them.

Of course, what you really want is gearbox with a twin 540 conversion. Have a look at this. Unfortunately  I sold both tanks with these gearboxes a couple of years ago.

https://www.tamiyaclub.com/showroom_model.asp?cid=109415&id=33435

 

[qatmix 794]

Thanks for this. 
 

Yes the pin should not come out (the other side is solid). I will bond that back together with some metal glue. I will also look at aligning it, I have done a quick test on the bench and it is fine under no load, and can even when I do it on the desk. 

The clutch is still a bit hard for me to grasp. I will take some more photos of the clutch  / gearbox and if you can point me into the direction of what you mean that would be appreciated. 

I have seen your great conversions, they are amazing and it is your tanks that made me want one of my own. This was a very good price and in reality it will only be run lightly once it is working so I think I will try to get this system working. 

[MadInventor 3884]

If you have no luck with the metal glue I can probably make you a replacement on the lathe, but I'll need a template or a measurement diagram to work from.

 

[MadInventor 3884]

Hi @qatmix I've had a dig in the loft and found one of the drive sprocket plugs. Yours if you want it. I could probably make a reasonable couple of copies on the lathe if you're not fussed about originality. Do you have a manual for the tiger ? That goes some way to explaining how to adjust the gearbox if I remember rightly. If not, I have my old one scanned in on a CD somewhere (It's one of the few models not in the Tamiyaclub manuals database, I could email some pages if I can find the CD.

 

[qatmix 794]

Thanks for this. It would be very good to have some (I am in no way bothered about them needing to be original). It’s going to be a runner. 
 

I do have the manual (from Tamiyabase), it is before Tamiya really got their manuals up to the standard they are now.

The gearbox is already assembled so the manual doesn’t have any instructions on how to assemble/ dissemble it.

I have been busy with some DIY jobs do not been able to delve further. I did spend a little time looking at the clutch. 
 

I removed the servo and moved the arm by hand. When I move it to the left or right the track does not stop, but it is putting enough load to slow down both tracks. 

 

[MadInventor 3884]

Ok, I'll knock a couple out. Will do them in brass or aluminium, so if you glue them in you and need to get them out you can dissolve the glue with thinners without dissolving the part.

 

[qatmix 794]

That’s fantastic, thanks for this. 
 

I have snuck away from the decorating, I’m still trying to understand the clutch mechanism. I’ve loosened the grub screw on the long shafts, and I can see the little friction pads. I can see some groves on the brass pad behind it. 

I’m still a bit confused about it all  

 

 

 

[MadInventor 3884]

I've got the sprocket caps done:

If you PM me a delivery address I'll get them in the post to you.

 

[MadInventor 3884]

On 8/31/2020 at 3:01 PM, qatmix said:

That’s fantastic, thanks for this. 
 

I have snuck away from the decorating, I’m still trying to understand the clutch mechanism. I’ve loosened the grub screw on the long shafts, and I can see the little friction pads. I can see some groves on the brass pad behind it. 

I’m still a bit confused about it all  

 

 

 

So I'm going to refer to your pics from top to bottom as pic1, pc2, pic3. 

In pic 1, you can see in the left of the photo the mechanism that operates the clutches. The clutch housings are the black circular items in the centre of the pic. As the big lever in the centre is rotated by the servo, levers press on one clutch or the other, depending upon the direction of rotation or the lever. The idea being that when the lever is centralised, neither clutch is being pressed on by the lever mechanism. As a lever presses on the end of the clutch housing, the clutch housing moves to disengage drive from the shiny shaft shown in fig2 and fig3. if it moves far enough it will start to press on the end of the shafts which then pushes them slightly towards the front of the tank. when this occurs the brass collar at the right of the pic in fig 2 should press on the fibre washer and press it hard up against the bronze friction bush (Its got small grooves in it to help with gripping.

The idea is to adjust the brass collar so that it does not impede the full disengaging of the main clutch, but still manages to press the friction washer onto the bronze bush .

Hopefully this will shine some light on it. 

The thing to remember about these tanks is that they were originally designed to run on an early 1980s 6V battery pack, which did not pack any punch. If the tank has seen a bit of use then the fibre washers may well have been worn smooth or contaminated with oil. Likewise, if you take apart one of the main clutch housings (Which are tricky to get back together as they're sprung loaded), you'll find similar material in them. Given the state of the bevel gear in the gearbox, I'd think about looking for alternative transmission arrangements. It is possible to fit the full option king tiger gearboxes in (With a bit of drilling of the hull, but these are only 380 powered and some of the gears are soft brass. Likewise, the conversions I did on my gearboxes got rid of the clutch issues, but I doubled the power of the tank, and had similar problems with preventing the bevel gears from slipping. If you think the bevel gears will hold, you could try making better friction washers, maybe by gluing wet and dry grit paper to a steel washer (If you don't want use the original fibre washers). This might improve the braking capability of the gearbox when trying to turn the tank.