BX25D: What is this? And should I drill it or weld it?

[dragoneggs]

Looking harder at you mounting and if I'm looking at it correctly, it looks like you are aren't reacting the moment well, and it is not going to be stiff/sturdy enough in the inboard/outboard direction. You have two studs but they are in line (waterline wise) if you understand what I'm trying to say here.

 

[tjkubota93]

Drill 2 holes and use 5/16 bolts like the others said. It would have been less damage to the paint to start with.

 

[dragoneggs]

Drill 2 holes and use 5/16 bolts like the others said. It would have been less damage to the paint to start with.

Still not going to be stiff enough connection if I'm reading this right.

 

[JK22]

Looking harder at you mounting and if I'm looking at it correctly, it looks like you are aren't reacting the moment well, and it is not going to be stiff/sturdy enough in the inboard/outboard direction. You have two studs but they are in line (waterline wise) if you understand what I'm trying to say here.

"Reacting the moment well"? Autocorrect error? I think I get what you're saying. I'm thinking I may slightly tilt the whole thing towards the rear. Still two bolts, but the rear bolt lower than the front. Does that address your concern?

 

[dragoneggs]

Unless you have no drill driver or drill bit, I have no idea why you wouldn't just drill a hole and bolt all that in place. Why take a chance on epoxy breaking and possibly running over your chain saw. Drilling 1/4" holes in the area is not going to weaken it. I prefer bolting on things like that rather than welding. Less damage to the paint that way and a quick paint touchup of the drilled hole will prevent any rusting. Also easier to relocate without cosmetic damage to the tractor.

Amen brother Gary ! Exactly what I say. I might lobby for 5/16" bolts...

While I'm a huge fan of adhesives designed in properly, from what I'm seeing is this is not a question of bolt size but more of mechanical advantage and how it can work against you. 5/16in or 3/8in vs. 1/4in is going to buy you little in the way of battling the prying load. See photo with load and reaction vectors. While they should be pointed in/out of the plane of the photo, you can see there is only about an half inch length (effective) couple to react the applied force at the top of the handle that is 25in length. This is a 50 to 1 magnifier. So you push 20lbs on the handle and you are developing 1000lb force on the bolt and flange not to mention the lack of stiffness when leaning on it.



I may be seeing this totally wrong so please feel free to correct me if I am misreading this.

 

[JK22]

While I'm a huge fan of adhesives designed in properly, from what I'm seeing is this is not a question of bolt size but more of mechanical advantage and how it can work against you. 5/16in or 3/8in vs. 1/4in is going to buy you little in the way of battling the prying load. See photo with load and reaction vectors. While they should be pointed in/out of the plane of the photo, you can see there is only about an half inch length (effective) couple to react the applied force at the top of the handle that is 25in length. This is a 50 to 1 magnifier. So you push 20lbs on the handle and you are developing 1000lb force on the bolt and flange not to mention the lack of stiffness when leaning on it.

View attachment 508335

I may be seeing this totally wrong so please feel free to correct me if I am misreading this.

I'm following you. My pictures don't reveal a crucial point. See pictures of mount below. Might change your perspective. The chain saw holder has a "shelf" that the saw rests on and is on about the same plane as the mounting point. The shelf is only about 8" above the mounting point. I think those force multipliers are lower with this info in mind.

 

[dragoneggs]

If the force is applied on the handle of the saw, it doesn't magically lower to the level of the bracket without creating/maintaining a 'bending moment' (force x length). The moment is transferred from the saw to the bracket via the clamp up on the blade of the saw (tight or loose). That said, I do see your point as the stiffness of the bracket is a factor BUT... you have to 'react' the bending of the bracket applied at the top of the saw handle at the attachment to the tractor somehow (bolt pattern). Just look at the design and spacing of the bolts on the clamp. And all that said, as long as you aren't getting a 'peeling' action on the adhesive you should be fine. Think of adhesive like velcro... great in shear and pure tension but peeling it makes it easy to tear. It boils down to stiffness and leverage.

 

[JWR]

While I'm a huge fan of adhesives designed in properly, from what I'm seeing is this is not a question of bolt size but more of mechanical advantage and how it can work against you. 5/16in or 3/8in vs. 1/4in is going to buy you little in the way of battling the prying load. See photo with load and reaction vectors. While they should be pointed in/out of the plane of the photo, you can see there is only about an half inch length (effective) couple to react the applied force at the top of the handle that is 25in length. This is a 50 to 1 magnifier. So you push 20lbs on the handle and you are developing 1000lb force on the bolt and flange not to mention the lack of stiffness when leaning on it."

Exaggeration. Unless you fall against it you are not going to push sideways with 20lbs of force on the upper most tip of the chain saw. Secondly, the practical aspects of the whole thing will show up only when you try it. Have you run this thing around some, temporarily glued on ? Think pitch, roll and yaw. My guess is that vibratory shaking around in the roll axis will be the primary problem (if there is a problem at all) in simply bolting the commercial saw holder onto the handy flat metal plate you are using for the attach point. Heck, bolt it on and go try it. If roll axis stability is an issue (due to your lunging sideways against the saw or due to tractor shaking and vibration) then devise a brace or added stabilizer that goes on down and mounts to the frame. There is some degree of inherent roll axis instability in the design of the commercial saw mount hardware -- you cannot overcome that without starting over and designing your own, maybe like a gun scabbard? Looks to me like you are within a few minutes' work of being able to go try it (bolted on of course.)