Bearings in Tammy KT idlers
10-14-2012, 03:53 AM
#1
Thread Starter
Bearings in Tammy KT idlers
OK, fellow tankers, I know I've been rather quiet of late. Long and hot summer with LOTS to do in and around the family schloss. Since it's mid October now and in theory the weather is turning cooler, time to get back to tanks. Right. Except for a couple days early this week, we're still running around in shorts and T shirts. Anyhow, back to tanks!
First up, I decided to fool around with the relatively new lathe that's been sitting forlorn and miserable on it's table in the tank fabrik all summer.
As most of you know, I have this fetish for bearings. Friction is your enemy, especially in competitions. Bearings in the KT idlers is a snap. What little drilling is needed can also be done on a good drill press.
First off, you need two bearings for each idler, sealed and flanged. One is 5 x 10, the other is 5 x 8.
The 5 x 10 fits neatly in the hole of the second wheel section sandwiched between the large outside section and the inside wheel disc.
You have to ease out the hole in the inside section from the inside only to a depth of 3 mm. I recommend a 7.95 mm drill bit for a finger press fit of the bearing in to the disc.
Next, take the idler axle shaft and clamp him in the drill press or lathe. Take fine emery cloth and shine him up, at the same time making sure your two bearings will slide freely on the shaft all the way down to the collar. Then dress up the axle end that fits in to the socket of the outer wheel section. I also cut off about 2 mm of the shaft on this end so there's no interference between the axle shaft end and the base of the cup.
Next, put the 5 x 10 bearing in his hole in the middle disc, from the outside. Mark where each hole for the outer disc screws go on the bearing flange, then taking the dremel grind down a small half moon shape so the screw bosses don't ground on the bearing flange.
Next, I replace the phillips screws that come with the kit with socket head screws.
Final step is to assemble the unit and check for free operation. On both my units, I had to remove the inner disc again and ease out the shaft hole boss to 6.5 mm for smooth turning. The original axle and disc are slightly off center. Drilling out the outer boss through at 6.5 mm eliminated all the interference and still left the boss to lightly ground against the idler arm.
This simple and cheap operation eliminates a great deal of drag on the track systems. Also, it squares up the idlers to help in track retention.
First up, I decided to fool around with the relatively new lathe that's been sitting forlorn and miserable on it's table in the tank fabrik all summer.
As most of you know, I have this fetish for bearings. Friction is your enemy, especially in competitions. Bearings in the KT idlers is a snap. What little drilling is needed can also be done on a good drill press.
First off, you need two bearings for each idler, sealed and flanged. One is 5 x 10, the other is 5 x 8.
The 5 x 10 fits neatly in the hole of the second wheel section sandwiched between the large outside section and the inside wheel disc.
You have to ease out the hole in the inside section from the inside only to a depth of 3 mm. I recommend a 7.95 mm drill bit for a finger press fit of the bearing in to the disc.
Next, take the idler axle shaft and clamp him in the drill press or lathe. Take fine emery cloth and shine him up, at the same time making sure your two bearings will slide freely on the shaft all the way down to the collar. Then dress up the axle end that fits in to the socket of the outer wheel section. I also cut off about 2 mm of the shaft on this end so there's no interference between the axle shaft end and the base of the cup.
Next, put the 5 x 10 bearing in his hole in the middle disc, from the outside. Mark where each hole for the outer disc screws go on the bearing flange, then taking the dremel grind down a small half moon shape so the screw bosses don't ground on the bearing flange.
Next, I replace the phillips screws that come with the kit with socket head screws.
Final step is to assemble the unit and check for free operation. On both my units, I had to remove the inner disc again and ease out the shaft hole boss to 6.5 mm for smooth turning. The original axle and disc are slightly off center. Drilling out the outer boss through at 6.5 mm eliminated all the interference and still left the boss to lightly ground against the idler arm.
This simple and cheap operation eliminates a great deal of drag on the track systems. Also, it squares up the idlers to help in track retention.
