HL-5 "U"

["Manic-Mechanic" 1,194]

I had this 5/8" bar stock so measured it off and got to forming the highly coveted "U" for the HL-5 Lights. I had these headlights mounted on the hood but never cared for the vibration and eventual cracking of the sheet metal. A tweak here and there decide my height and drill, tap a plate, tap the rod ends

[8ntruck 7,016]

You mentioned vibration.  While the headlights will not cause fatigue cracks in the 5/8 round bar, but the bar itself is a large tuning fork.  I wonder what the natural frequency is for that bar - hopefully not a multiple of 3600.

 

Would be a simple FEA model to figure that out.  Unfortunately, I'm retired and no longer have access to that software.  Maybe next winter when I'll be mentoring the robotics team again.

Edited July 8, 2022 by 8ntruck

["Manic-Mechanic" 1,194]

Just now, 8ntruck said:

You mentioned vibration.  While the headlights will not cause fatigue cracks in the 5/8 round bar, the bar itself is a large tuning fork.  I wonder what the natural frequency is for that bar - hopefully not a multiple of 3600.

 

Would be a simple FEA model to figure that out.  Unfortunately, I'm retired and no longer have access to that software.  Maybe next winter when I'll be mentoring the robotics team again.

Now I am curious but not too intrigued. This bracket is based off the factory HL-5 Headlight Kit, here is this part fully fabricated, including the 5/16" threaded holes as well as, mounting holes..

[8ntruck 7,016]

Well, if the designers at Wheel Horse did their job well, things should be fine.

[wallfish 17,011]

9 minutes ago, 8ntruck said:

You mentioned vibration.  While the headlights will not cause fatigue cracks in the 5/8 round bar, but the bar itself is a large tuning fork.  I wonder what the natural frequency is for that bar - hopefully not a multiple of 3600.

 

Would be a simple FEA model to figure that out.  Unfortunately, I'm retired and no longer have access to that software.  Maybe next winter when I'll be mentoring the robotics team again.

Interesting! Never ever thought of that.

Would it do? make noise or vibrate more if it was?

[8ntruck 7,016]

When something on the tractor starts vibrating at the natural frequency, or one of the harmonics of the natural frequency of the headlight bracket, it will start to vibrate, most likely like a giant tuning fork.  Nothing serious probably, but if one were using incandescent bulbs in the headlights, it the shaking would shorten the bulb life.

["Manic-Mechanic" 1,194]

24 minutes ago, 8ntruck said:

When something on the tractor starts vibrating at the natural frequency, or one of the harmonics of the natural frequency of the headlight bracket, it will start to vibrate, most likely like a giant tuning fork.  Nothing serious probably, but if one were using incandescent bulbs in the headlights, it the shaking would shorten the bulb life.

Now you have got my attention, never even imagined such an effect. I'll have to make a mental note of this, hopefully that will not be the case! Lol 

Edited July 8, 2022 by "Manic-Mechanic"

[8ntruck 7,016]

As I mentioned, since you based it on a factory kit, all should be OK.  If it does end up getting the shakes, you could add a brace between the two legs in the neighborhood of the fuel pump.

[953 nut 55,297]

The leg on the left (as viewed from the front) needs to be shorter than the one on the right to clear the muffler. This is one of many little tidbits that @Wild Bill in VA told folks during the parade at the big show.

["Manic-Mechanic" 1,194]

1 hour ago, 953 nut said:

The leg on the left (as viewed from the front) needs to be shorter than the one on the right to clear the muffler. This is one of many little tidbits that @Wild Bill in VA told folks during the parade at the big show.

The last one I set up this had to be taken into consideration, I do believe there was some tweaking on both sides, mostly outwards an down

["Manic-Mechanic" 1,194]

Well, here is what I ended up with from table scraps, it is 1-1/2" wider overall as I did have to spread the last one on the 1045 and it was factory. Now some 90° brackets

Now I would be curious to know the vibration frequency of the "fork" as it is different dimensions! 

Edited July 9, 2022 by "Manic-Mechanic"

[19richie66 17,508]

You could always weld a small crossbar between the uprights(if it would clear the hood) to alleviate the vibrations if they were a problem. 

[8ntruck 7,016]

Just educated guessing here, making it wider will probably lower the natural frequency.  How much of a change?  Mounting method for the bracket and the weight of the head lights and how they are mounted will all have an effect on the assembly's natural frequency.  Since the change was made between the mounting area on the frame rails,  it may not have much of an effect.

 

Disclaimer: it has been a couple of decades since I did any work with vibrations.  This is opinion, and I have not run any calculations.  Essentially, I am speaking in generalities.

["Manic-Mechanic" 1,194]

I will have a real fun time attaching the headlights and then adjusting the angle for the first time. A tendency to over-think is easily discerned, everything will work perfectly, of this, I am sure.

I will use a lifting I bolt in 10mm which is somewhat compatible with 3/8th's to the light and 5/16th's to the bracket. Little trimming on the threads and some flange nuts....

Edited July 10, 2022 by "Manic-Mechanic"