View Full Version : Laser Cut Stop Blocks

Fri 13 November 2009, 19:16
Thinking about adding this part to the kits, it would cut some time out of the build. It is .250" thick. Just wanting to get a litle feed back before I made anymore of them. All it would need is to be tapped and the hole for the prox drilled.

Gerald D
Sat 14 November 2009, 10:56
Leo, I have recently made those stop/switch brackets in a similar way. The hole for the sensor was also laser cut and slightly slotted. (The sensor is 12mm diam)

They were welded to the cars:


Sat 14 November 2009, 12:21
Yes, yes, YES. Significant time saver!
...and since I am about ready to start a CNC Plasma machine, I will be ready for them.

Sat 14 November 2009, 15:18
Yes - I also think this would be a good part to add.

Sat 14 November 2009, 16:22
Adding the hole would be no problem, I had left it out just in case some one drilled the holes in the rail a little off they could adjust the prox some. I think I will start making a few, Thanks guys

Sat 14 November 2009, 16:25
Gerald , I think slotting the hole would be a good ideal , you already have the hole and still have some adjustment.

Sat 14 November 2009, 17:15
That car-stopper is an excellent idea. Big timesaver.

Gerald D
Sat 14 November 2009, 22:30
The idea is not fully mature yet . . . .

For welding the part to the cars, they should get matching lugs and slots.

I have avoided this idea for the published drawing set because the bend tooling is not easily found all over the world. Some guys are going to make a mess of the two short bends with the un-bent bit in the middle.

To enable the bending, the notches must be cut in quite deep, making the "fingers" a little weak for stopping a heavy gantry that is running away. I welded up the notches after bending.

Sat 14 November 2009, 23:04
Great insight - Learning new stuff all the time here is cool!! Thanks Gerald!!!

Thu 19 November 2009, 16:46
What about a profile like this?

Thu 19 November 2009, 18:52
I dont think that would be as strong as you are removing material from the part and making a sharp inside corner that would make a good place for the metal to start cracking if it did start seeing alot of crashes. I dont think the part I have now will fail. The tab in the middle could be removed to make forming easier , but then you would have to weld the a tab on, but it would still be alot less labor than before. But keep the ideals coming.

Robert M
Thu 19 November 2009, 19:25
Scary and cool how two guys who never met, not even close by can think alike :eek: :cool:



Amicalement, Robert ;)

Thu 19 November 2009, 20:48
Yes it is, have you had any problems from yours?

Thu 19 November 2009, 22:29
So the tabs can be wider. Run them out to the edge of the circle to create more mass.

Did you make the mount holes 8 MM or did you go 5/16.

Also a technical question. Compensating for length in a bend like this. Do I add the thickness of the steel to the bend or half the thickness or what?

If I bend a piece of .25 inch steel 90 degrees and want the bent tab to be 1 inch, how much more do I need to add for the correct finished length?

Or is what I add based on the die used when bending the steel.....

Cool stuff !!!

Thu 19 November 2009, 22:49
More Mass - Looks like an M with a smiley face !!! :D

Gerald D
Thu 19 November 2009, 23:32
Take a piece of tin (from a beer can if needs be) cut it approximately to your shape and then test it to see where it wants to bend when you hit the point - this will tell you where to add more metal (and where you can trim it away). Mike's more mass (MMM) is not going to make it any stronger :) (you want more width at the bend line, not at the tip)

Bending of steel plates - how it is done and calculated (http://www.mechmate.com/forums/showthread.php?t=438) (Post #3)

Fri 20 November 2009, 05:33
MMM - Funny !

So why not just bend the 2 - 90 degree bends in a piece of square plate .25 inch, then cut a piece of 12 or 14 gauge steel with a few holes in it that can be lined up easy and plug welded to the flat part of the stop block.

All it does is hold the stop sensor anyway and it would be very quick to put together and not a challenge to make sure all the little parts line up and stay square.

Gerald D
Fri 20 November 2009, 06:02
Then the sensor hits all the screws holding the rail to the beams.

Fri 20 November 2009, 06:30
It would have the same finished deminsions as the regular part does.

Fri 20 November 2009, 08:10
Mike ,if you figure your bends on ID using a .120" rad Punch you would need to add .039" to your desired length . If using OD measurements you would need to subtract .211" in each direction for each leg so .422 per 90 deg bend. If you change your die Rad these numbers would change a little. I can give you the K factors to use if you tell me what punches you will be using and if you will be coining or air bending your parts.

Fri 20 November 2009, 08:34
:eek: My head is on fire !!!! - I'll digest that for a while :D . Expert I am not but I figured it may have something to do with the die you are bending with. Thanks for the info - and yet again I am amazed at the amount of knowledge on this forum!! Thanks G !!!!

Wed 25 November 2009, 13:59
I finally understand the "Hitting the screws" comment that Gerald made.

This is basically what the other guys did. I just drew it out so I could make since of it.

Wed 25 November 2009, 16:42
Minor edit to leave as much steel in the part as I can.

I will see if the kerf is wide enough to alow the part to be bent with just a pierce straightline cut of the legs and tab area. (Smile area)

J.R. Hatcher
Sat 28 November 2009, 11:06
I think this may solve a few concerns. By cutting the oval completely out, it can be flipped around if necessary to miss the rail bolts, then welded back in. The 2 stop ears become 1 and are now very strong. The bending also becomes less of a problem. What do you think?

Gerald D
Sat 28 November 2009, 14:52
The proxy must have a clear view of the rail - your "bridge" will block the view of the proxy.

J.R. Hatcher
Sat 28 November 2009, 16:51
The drawing is not absolute, I was after the concept. Imagine it tweaked a little so it doesn't sit exactly over the bridge? Someone who understands the material consumed in the bend should tweak it. Thanks

Sat 28 November 2009, 21:31
I am happy with the one from Geralds original design converted over to a formed part. I have crashed it several times into the stops with no damage or bending other than a little mushrooming on the end from being hit over and over. I can make them out of 100 min yield steel and then there would be no wway of breaking it. But the 50 Min seems to be holding up just fine.