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ST4 restoration of Frankie the Frankentrac

Two days of cleaning and painting, then a trip down the hill to McLendons in Sumner to get some new hardware. They have many aisles of nuts and bolts and special hardware of all types and grades, only Tacoma Screw has. Better assortment, but they are much farther away. So, got some new large nuts and big bolts, almost ready for reassembly.

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Absolutely sweeeeeeeeet....Looks great
Finding an outfit that has a huge selection of fasteners is tough these days.
So many hardware stores...(Big box) have stuff in little plastic packs of 2 or so....

Finding grade 8 and fine thread is tough....Then when you want Allen head stuff....or Torx type...even tougher.

Nice to have a place close...

We have an ACE hardware store that has one of the best selections I have seen anywhere other than the big industrial supply houses up in Portland....

Being able to walk the aisle and pick and choose is nice

The prices are not cheap.

If I need any large quantity I hit ebay and sort through the many sellers.
Usually cut the cost by half or more.

Cat is looking great
 
Big milestone today- it's back on its wheels :) (y) Next I'll put the front big wheels on and then the drive sprocket axle housings and while the body is off I'll temporarily install the engine and trans to sort out the mount and chain adjustments.
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The bogie tires are okay for now, but really struggling to find some replacements. Sent a couple of inquiries, but no responses, so I'll have to get on the phone.
 
Johnson's in Maple Valley has a great assortment of hardware. But it's a little farther out than Sumner. I'm in there all the time.
 
Reamed the axle housing pivot pin holes to .875", inserted the pins after cutting them to length and drilled the pin capture bolt holes, slid the sprockets on and everything is nicely aligned and fitting. Engine and trans are next.

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I'm still waiting to see how those pipes function. in mine they are threaded from the axle to a block in that cross tube.
 
I used solid fork lift tyres for the bogie wheels

4.00-4 CAMSO SOLIDEAL RES-550 (SOLID) (FITS RIM SIZE 2.10-4)​

they work great and are totally puncture proof - bit heavy but probably not much difference to foam filled
 
Engine and variator test fit - working out the sequence of installing the various bits, sprockets go on first, won't go on with muffler installed.
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Next few steps are getting the sprockets and chains installed and adjusted, put some oil in the engine and dive it a test run, set timing, etc. Then remove it all again and start work on the body.

Ordered a couple of new Continental SC10 tires for the bogies, from B.C., so will be interesting if they will actually sell them to me, been rejected by a couple of tires vendors already. If they will sell me 2, then I'll order a bunch more. Not a bad price of $65 each, too bad that's not $CAD.
 
Jphoenix said:
Engine and variator test fit - working out the sequence of installing the various bits, sprockets go on first, won't go on with muffler installed.View attachment 171731

View attachment 171732

Next few steps are getting the sprockets and chains installed and adjusted, put some oil in the engine and dive it a test run, set timing, etc. Then remove it all again and start work on the body.

Ordered a couple of new Continental SC10 tires for the bogies, from B.C., so will be interesting if they will actually sell them to me, been rejected by a couple of tires vendors already. If they will sell me 2, then I'll order a bunch more. Not a bad price of $65 each, too bad that's not $CAD.
Click to expand...
Was curious if the square cut tires or the rounded ones work the best for the wheel guides.
 
Aklynxhunter said:
Was curious if the square cut tires or the rounded ones work the best for the wheel guides.
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The Continental IC10's are the ones JimVT is using, so I expect they will work fine. Can't find Trelleborgs anywhere, so there Conti's are my only choice at this point.
 
Found some Trelleborgs with the help of a very friendly guy at Cascadia Tire in Burnaby, BC. He's working on shipping, price is $89 each which is better than the Continental SC10 cost now of $272!

I aligned the variator with the frame, it's situated very squarely in position, then adjusted the axle rods until the axle housing are located in the center of the cutouts in the body sides, then found I needed to remove some links from both chains. Now both sides are evenly distanced and centered in their adjustment. I also found the right chain was indeed one link longer than the left side - which explains why it was so hard to get proper tension on that chain. Both axle housings were way too far forward, bending the front edge of the body cutout quite a bit. Now they will be located in the center of the cutouts.

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Of course, there's always something - the new muffler fouled the left brake disc, so I trimmed some of the excess muffler flange away to provide clearance. Getting all this adjusted now before the body goes on is really making all this easier. Also, I discovered one must install the variator tension rods (the long rods on the bottom of the variator that go the C channel) prior to installing the engine.

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You definitely want those axles as far forward as you can or the sprockets will hit the tyres - your machine is two band track with big front wheels and the sprockets are too close together - the factory made the big front wheel machines with 3 band tracks and much wider spaced sprockets that straddle the tyre, but as a consequence of the wider sprocket spacing they de-tracked more easily when the track twisted over uneven ground. A number of machines were built like yours with two band tracks and big wheels to try and get the best of both but they need the sprockets well forward to clear the tyres - you will be surprised how much things flex under load and even though the tyres look well away when stationary they will hit in use.
 
I agree with your concerns Puckle and one of the issues with the sprockets hitting the right front big tire on this machine was the bent sprocket mounts, that caused the sprockets to be angled inward and very close to the tire. I will be removing the springs from both big wheels today and moving the wheels through their full range of motion to see how much clearance exists with the sprockets properly located and the big wheel at the fore most position in their arcs. In worst case, I have links I can put back into the chains to move them farther forward. Right now, where the axle housings are, they have about one inch further forward to go before they hit the cutouts. I'm also limited how far aft the axle housing can go before the brake discs start to hit something like the muffler, already had to trim the left side. Next item are the brake anti-rotation levers - they will foul the muffler as well if they go back much further. Another concern are the sprocket teeth, I've downloaded the sprocket diagram someone laded to this forum and it looks like the sprockets on this machine are about .5" larger in diameter than normal 2 band machines, but still have to measure and finalize that.

For sure, everything is close tolerance and every little adjustment means something else needs tweaking. I've thought about radical solutions like moving the big wheel mounts farther back or maybe even smaller diameter big wheels, like 15 inch instead of 16, but more to come as I progress.
 
Jphoenix said:
Another concern are the sprocket teeth, I've downloaded the sprocket diagram someone laded to this forum and it looks like the sprockets on this machine are about .5" larger in diameter than normal 2 band machines, but still have to measure and finalize that.

For sure, everything is close tolerance and every little adjustment means something else needs tweaking. I've thought about radical solutions like moving the big wheel mounts farther back or maybe even smaller diameter big wheels, like 15 inch instead of 16, but more to come as I progress.
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I'm certainly not a Trac expert by any means, but a couple of thoughts.

Your sprockets do not appear to be the OEM bronze forged, but torch cut steel. If I was a betting man, I would bet that when that was cut the person doing it tried to compensate for assumed wear by adding .25" in all directions. This in turn closed the gap between your big wheel tire and the sprocket . . . which drove the need to 'find' spacing in different ways.

It has been discussed for years, by many, to have a batch of the bronze alloy sprockets reproduced by a foundry. Someone here (Tom?) will know if that ever happened. The other issue was the use of steel for the sprocket. The sprocket was designed to take the wear (when they were readily available) instead of the grousers. Sticking with steel will only create bigger problems down the road. If those bronze never got cast, I would suggest cutting it (using the sprocket diagram) out of UHMW poly. The cost would be low, it's readily available, high wear resistance, self lubricating. When they start to wear, flip them. When they do wear out, cut more.

And, it would free up some space between the sprocket and tire.
 
Dave, yes there is an effort underway now to cast some new bronze sprockets. I also have some UHMW can use as a backup. These steel sprockets are typical of the Mclarty rigs. I'll find a happy medium for the sprockets at some point.
 
I have STL files for 3d printing the mould patterns for the sprockets if anyone wants them - can't attach here but can send as e-mail attachment. They are in two halves so you can split the mould, but may require a bit of work to increase the back of the lugs to support the inner rubber coated ice breaker ring - the first ones I made were a bit thin here so I added a spacer before making the sand mould. It doesn't look like Frankie has those rings though so may not be required - the 3 band sprockets don't have them either.
The files are at full size and need printing with a 1.2 expansion factor to allow for shrinkage of the silicon bronze as it cools.
 
Puckle said:
I have STL files for 3d printing the mould patterns for the sprockets if anyone wants them - can't attach here but can send as e-mail attachment. They are in two halves so you can split the mould, but may require a bit of work to increase the back of the lugs to support the inner rubber coated ice breaker ring - the first ones I made were a bit thin here so I added a spacer before making the sand mould. It doesn't look like Frankie has those rings though so may not be required - the 3 band sprockets don't have them either.
The files are at full size and need printing with a 1.2 expansion factor to allow for shrinkage of the silicon bronze as it cools.
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Thanks Puckle, the guys here working on new sprockets have the old patterns used once before, so I think we're good.
 
Man I love seeing all the progress and good work on this!! I'll take the blame for bending the slots on the forward adjustment on the big wheels. When I first got that machine the adjusting nuts were frozen and the guy I bought it from said "don't even try, they need to be cut off". Well after a couple weeks of Kroil, they loosened right up. So not knowing much, I just jammed them as far forward as I could and I noticed it was bending those slots but otherwise I didn't see any issues with it so I just kept pushing them forward. I also had longer springs custom made so it would sort of jack up the front a bit and therefore have just a little more clearance. But I was also curious how you were going to deal with this issue. I'm sure having things lined up helps somewhat but I also thought of moving the front wheel mount back etc. But that kind of work is over my pay grade, lol! I'm sure you'll come up with a much better solution. Great work and looking forward to seeing this back out on the snow.
 
It’s not over yet Sno, still have to swing the big wheels up and check clearance, may end up moving it back forward as puckle suggested. I’ll just clean up those mushrooms you made 😃 - but with the sprockets square and straight now, maybe it will be ok as is, we shall see. Right now trying to clean up that crazy handbrake arrangement, I did get it free, but they were really stuck on good!
 
Cleaned up the variator sheaves today and got some POR-15 on them.

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They'll get a second coat as always, these get exposed to moisture and need all the protection they can get.
 
Reassembled the variator sheaves with new bearings and hardware, all working as it should. Ordered new belts for the tracks from Fall Line this morning, not looking forward to making new tracks - been there done that before, not as much fun as it looks.

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Photo below shows the installed the handbrake actuating rod, the long steel shaft is nested inside two delrin bushings, hard to believe how stuck that shaft was inside the bearing, but they're freed up now. Getting closer to engine run.

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never seen that handbrake system before, wonder if it is a one off or if it is something Alex McLarty came up with when he did the disc brake conversion - does yours have a remote servo on the brakes by the way?
 
Puckle said:
never seen that handbrake system before, wonder if it is a one off or if it is something Alex McLarty came up with when he did the disc brake conversion - does yours have a remote servo on the brakes by the way?
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I believe it’s a Mclarty mash-up, overly complex for just pulling on a couple of cables, but it took some time for the fabricator to make. At least now it will actually work.
 
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