"DIY" Carto Punch

[markfm]

I came up with a carto punch that anyone can easily "make". It actually just takes buying two parts, the hub and the proper size sheet metal screw. The metal piercing part is easy to replace (buy several screws).
Hub
http://www.drillspot.com/products/157425/Lovejoy_AL050_Aluminum_Shaft_Coupler_Body
$4.95, free shipping

This is the body of the punch, that the screw goes into. It's about 2/3" wide, a bit over 1" diameter, 3/8" wide hole through the middle. The shaft is close enough to carto diameter so you get little deformation when you put the hole in, and it's impossible to have the screw skitter across, since it goes into a 1/4-20 hole in the side of the hub.

The center of the screw hole in the hub is just about 1/3" from the edge of it. If you need the hole to be higher than 1/3" from the carto base, just leave a little of it exposed.

Screw
You need a 1/4-20 metal piercing screw. Right now I have 3 options:
Amazon.com: 25 1/4-20x7/8 Mirror Mounting Screw Phos W/Nylon Washer: Automotive
$15 delivered for a pack of 25. This is the one that I have in hand right now, did my initial tests with. Downside is they do have an organic phosphate coating, which I don't sweat, though you can always steel wool the tip if you wish, or just punch a couple holes in an old carto to scrape the finish off. Alternately I believe this is the same part: Mirror Mounting Screw Phos w/Nylon Wash, at only $0.32 each plus shipping.

S.S. GM Mirror Mounting Screw 1/4-20 x 1-1/4
Slightly longer, zinc coating instead of organic phosphate, $0.66 each. I have a set of 5 coming in this afternoon, but am confident they will do the job.

Ribetautoparts shipping is reasonable.

Self Tapping Screws - 1/4"-20
I have not ordered these, but it looks like either the MTS-1095 or MTS-1096 will get you a plain 410 stainless steel screw, no coating. Base price for a box of 100 is either $19 or $21, but they have a picking fee plus higher S&H, ends up running almost $40 for a box.

You'll need a 1/8" allen wrench to remove the set screw that comes in the AL050 hub, then either a normal wrench or phillips head to put the screw in.

Use
Not much to it. Put a screw into the hub. Slide the carto in. Tighten the screw until you just feel pressure, then two full turns of the screw. Back the screw out until the carto slides out.

I use fusion cartos in an M1A1 tank. The M1A1 has a fairly narrow bottom cap, and the fusion has a flange, so I just slide the carto in until the flange meets the hub and punch away.

 

[Bovinia]

Can't wait to gather all the parts to try this! Thank you Mark

 

[FreeFire]

Fabulous!!!! Thanks a million Mark!

 

[markfm]

Sorry it's a long post. It really is as easy as 1) Get hub, 2) Get screw, 3) Punch hole in carto

 

[DRLyman]

Thanks for the info. Just ordered the parts needed. Can't wait to try this out. Thanks!

 

[arkador]

Mark,
the problem I see is that you need a tool to turn the screw, the one I have been looking at has a thumbscrew, and I could tighten by hand to pierce.

 

[markfm]

I spent a good amount of time searching for a piercing thumbscrew, came up with zip. Grinding a standard thumbscrew can be done, but is a pita.

At the end I figured that simple wins, since I don't see people carrying a carto punch around.

If you want to bypass the little wrench, you can superglue a 1/4-20 wingnut on. Use one with a shallow pitch, else use the longer 1-1/4" screw.

I ended up liking the wrench after having tried a couple of the saddle valves, since it makes turning the screw effortless; the screws I'm using have the washer flare at the bottom, so the wrench doesn't tend to slip off. A pair of pliers would work, too, but the hex head is a common size. I tried four different cheapie wrenches from exercise equipment assembly kits, they all fit.

If you find a good pointed hex head thumbscrew, please post it. I just keep a spare wrench with the hub, but certainly cool if you see a thumbscrew. The key parameter is 1/4-20 size, since that's the hub screw hole size.

 

[kwcharlie]

Oh ya, when i need that hub for an encoder there won't BE ANY, thanks , those motors will just have to stop working while you punch cartos with the hubs i need.

 

[markfm]

What are the odds that the right hub would be the only one that also, for no reason I could see, has free shipping?

 

[Bovinia]

I guess my needle nose pliers will have a little wrench to keep it company in my desk holder soon

 

[MASTER0FDAMPF]

Couldn't you just take one of these:
J.W. Winco, Inc. - Wing Nuts
just a wing nut...and cut the head off your self tapping screw. Put a little JBweld inside the wingnut, thread onto the back of the screw (Where you just cut the head off).self tapping 1/4-20 winged thumbscrew.

Or use a crappy 1/4-20 wingnut (about 20-50c at HW stores) threaded all the way up to the head of the screw and JB weld that sucker in place.

2 ways to create the needed 1/4-20 self tapping.

Dont trust JBweld? Use a nulon lock nut and a lock washer inbetween that and the wingnut and no JB weld required. Total cost - around a buck in the hillman isle at any major HW store. maybe a buck and a half if you go stainless.

http://www.myhardwarestore.doitbest...Fastener-model-180147-doitbest-sku-721883.dib
Sears: Online department store featuring appliances, tools, fitness equipment and more
Hillman 56358 Split Lock Washer, 1/4" Split Lock Washer

 

[markfm]

Absolutely, MOD I'd go the glue route, probably, if I wanted to add a wing nut.

(Someone could also run a tiny coop, get 10 - 20 people to share a box of the stainless screws, if anyone wants to try them. It looks like they have proper piercing heads, and no coatings at all, though the coatings do rub off if you just punch a couple initial holes in a junk carto.)

 

[pizza2me]

Great ideas mark and mod!! I've thought often if there could be something as simple as this. Just never looked/found the hub thingy. But...

Would you want to glue, etc the wingnut to the screw if the screw is going to dull? Just get a bunch of wing nuts too? Or could they be reused?

 

[markfm]

I don't actually use the wingnut, I just use a wrench with the hex head screw. I use one of those little flat cheapie wrenches, the ones that come with all the "some assembly required" things, it's a standard hex size. It's really fast to do two turns of the wrench, and I leave the punch with my blank cartos, so I don't sweat having a small wrench there.

Any punch will dull, but these screws are designed for metal piercing, and they are pretty cheap.

Finding the hub wasn't bad when I figured out that normal set screw collars were too narrow-walled, but the darn screws took hours to find

 

[MASTER0FDAMPF]

JB weld...no. Removal is VERY difficult.
That is why I suggested the lock washer and lock nut ideas as well. at 6$ for a box of 50 wingnuts, 40 screws for 6.50, JB weld about 6$

around 20$ with 40 replacements. You can always just file to a point anyway when they get dull.

1/4-20 x 1 Phillips Oval Machine Screw (40 pieces): Amazon.com: Home Improvement

Great ideas mark and mod!! I've thought often if there could be something as simple as this. Just never looked/found the hub thingy. But...

Would you want to glue, etc the wingnut to the screw if the screw is going to dull? Just get a bunch of wing nuts too? Or could they be reused?

 

[markfm]

Yeah, the flat tips are easy to find, but grinding is a pain, especially if you start from scratch. I did grind a standard 1/4-20 thumbscrew, but life's too short for me to want to do that more than once I figured pointing people towards a Buy, rather than a Make, would be simplest.

(The 1/4-20 410 stainless screws I put up a link to are likely ideal, not even any coating to remove by doing a few test punches, but for that you would want to have like 10 people buy a box as a tiny coop, get a box and each person would pay $6 total to get 10 screws, $4 towards the original buy and $2 to cover the repackaging and mailing to people.)

 

[Lady M]

Thanks for posting this

 

[Bovinia]

I am now using the hub and the mirror mounting sheet metal screws that Mark listed and this setup is so simple, and it just plain works...great! Mark graciously sent me a couple of the screws he got from Amazon, and with a couple of punches on a dead carto, the coating on the screw is gone so not an issue.

I did dig up a hex head wrench but honestly haven't had to use it. I've been able to grip the hex head on the screw tight enough to turn it and punch cartos just using my fingers

Thank you for all of your research and bargain hunting Mark! I love simple. I just took some pics, getting them resized for upload.

 

[Bovinia]

Pretty self explanatory, sorry for the blurry one.

 

[markfm]

Thanks for posting the photos, I was too lazy to take any others

The screw hole is centered, so cartos can be put in from either side, whatever is convenient.