Steamhammer is an excavator..... but with problems. The engine back of the excavator is waaaaaay oversized for the rest of the toy and even when TF'd right looks at an odd angle. And the shovel is the wrong way round - surely an excavator shovels pull in towards the rest of the vehicle? A rotational joint near the end of the shovel arm could have fixed this easily. The shovel arm bends at it's base, 1/3 of the way along and where it meets the shovel. One of the arm connectors for Devastator is on the shovel arm, and his spark crystal along with 2 inaccessible minicon ports on the shovel with another two one the rear of the vehicle.
Transformation to robot involves the oversized engine forming the legs, the digger arm his left arm and the right coming from within the toy (with the other arm connector) - though exactly where it goes when you TF it back isn't clear. The treads lock into the body and out pops the head.
The robot mode looks reasonable if you forgive the left arm formed from the shovel arm. Three members of the construction team - Steamhammer and Duststorm/Wideload - have odd left arms ! Like Barricade he's ended up with Minicon ports on each knee. The articulation is mostly ok - knees bend, there's a swivel joint above them, universal hips, the waist & neck turn as do the shoulders which also bend to the side. Both arms have a bicep joint with the left having an elbow on the bend in the shovel arm. The right arm has a double bending elbow with a Minicon port on the outside of the elbow and a 5mm peg hole on the hand.
Steamhammer's combined robot body mode is significantly more solid than Stormjet's and nearly at a par with Onslaught - from robot the treads come out of the body, the arms fold in and peg in place, the treads peg in the back and the head flips out of the cabin on the shoulder. A tiny bit of fiddling with the legs reveals the lower connectors.
Steamhammer's got some flaws as detailed above but I feel that an excavator isn't the ideal vehicle mode to be forming a combiner's core. A truck might have been better but they'd already done a construction vehicle truck in Energon earlier the year in the form of Demolishor.
Steamhammer's Japanese name was Scavenger and he was only available in the EX-01 Buildtron giftset exclusive to Toys R Us in Japan.