Linear puncher help

This is a video of our linear puncher it has 7 rubber bands on each sides. It has normal motors. It can’t even pull back all the way. It should be able to pull it back all the way. Please help us.

I don’t actually have any experience with these but from what i’ve heard, 14 elastics sound a bit high. I’ve seen teams do it with closer to 8. try lubing your slides and making sure there’s no unnecessary friction or binding. you may also need to play around with the weight of the puncher itself.

Are those standoffs in the front where there ball rests when the shooter is pulled all the way back? If so, I can tell you what the problem is right off.

You want the ball to be in contact with the puncher for a very small distance (1/2" to 1" roughly). I’m guessing you kept adding rubber bands because the ball wasn’t going far enough. When you reduce the contact distance you’ll be able to use less rubber bands to get a full field shot. Also, you should reduce the length of the puncher. You only need 2 rack gears at most. My puncher uses 1.5 rack gears.

Also, 14 rubber bands is to much, our prototype was able to pull of full court with 4 total #64 rubber bands (two on each side)

14 is a bit much. Make sure no screwheads or nuts are interfering with the travel either. Seen that before.

With a good quality build, all you need is 2 #64 rubber bands on each side.

Dont use 14 bands, use 4 - 8. Also make the puncher push the ball only about 1/2 - 1 inch. Lubing the slide helps alot too.

Here is the improvement that we made to our linear puncher.

You should move the standoffs up at least 2 inches. You only want the puncher contacting the ball for about half an inch.

Alright, I’m just going to try to give you the best advice possible, including summarizing what has already been said in this thread. The ball should only be in contact with the slide for about an inch. Your slide is far too long and uses far too many rack gears. Count how many teeth are remaining on your slip gear. Then, use that many teeth, plus a few, on the rack gears. Make the slide rail itself considerably shorter. Use a string or nylon spacer stop. Your goal should be to reduce both weight and friction. It’s the little things that affect the performance of a linear puncher. As was previously stated, your LP should work with around 4 to 6 #64 rubber bands total.

+1 to this. You want to punch it not push it.

Here is our next prototype of our linear puncher this is probability going to be one of our last we need to remove a few racks and stuff like that.

Also, on another note, don’t dry fire quite as much as in the videos. The more you dry fire, the more it wears down on the stopping mechanism, whether you use a nut on the linear slide, nylon rope, and so on. No matter the type of stopping mechanism, extra wear could be the difference between winning a match, or having your linear puncher come out of the slide.

I found that if you just cover the stopping pin with nylon spacers in between all the points where it contacts the rail, then that prevents a majority of the bending and gives minimal risk to dry firing.

If you do everything you can to reduce friction, and it still doesn’t work, you may just have to rebuild. Our LP that we built earlier in the season had the same problem and we still haven’t figured out what caused it.

Hi, we are 1815 Delta, and we have a puncher too that had the same problem, but is now fixed. Here are some things that could be causing the problem, and check each one:

  1. Is there too much friction between the puncher and the rail it’s standing on?
  2. Is the slip gear too tight against the puncher ?
  3. Are there too many rubber bands?
  4. Are your motors wearing out?
  5. Do you have too few motors?
  6. Do the gears have a lot of friction?
    Here are some solutions:
  7. Take the puncher off, and put WD-40 on the rails.
  8. Try raising the slip gear (It might take some trial and error)
  9. Try ordering new VEX-Legal rubber bands (Don’t get the thick ones, they wear out faster)
  10. Try ordering new motors (They are really cheap, only $10 each!)
  11. Try to attach another motor to the puncher, or have a gear ratio from the motors to the puncher.
  12. Make sure that the bearing flats aren’t worn out or breaking, this could cause damage to the axle and metal if it happens. Make sure that the path of the axle is straight, the straighter, the less friction. Check if any axles aren’t bent, but if they are, just hammer the axle on a flat surface until it’s straight.

Aerosol based lubricants are actually against the rules. Instead of WD-40, I’d recommend white lithium grease.

I think I accidentally posted the wrong type of WD-40. Sorry.

So is there a recommended angle for LP’s. I was thinking 30-40 degrees.

That would probably work. Take into mind that it’ll only be able to shoot from one position in that case. Check out the angle that 2r uses on his lp seemed to work well.