I heard this old Pronto calling...."HELP!!"

[Meridian_Mike]

Hello all.....
I have had this old Colonial "Pronto" knife in my box of dead knives for a while. When I was on my way down to my shop yesterday, I heard it calling my name. It was time to see what this Pronto needed to get him operational again.

There was no spring action at all so I figured I would find a broken spring when I opened it up. Actually, when I got inside, there was no spring at all.

That crunched up roll pin is where the spring used to attach.
SO.... onward to the clean-up...

The knife was originally put together with brass roll pins. LOL..... plastic scales, roll pins, I don't figure that Colonial wanted this knife to last too long.
After clean-up you can see that the spine is nothing but a spacer really. It doesn't serve the same function as a spring in a folder.

Here is the push-button mechanism...... really simple.

Well, I got so engrossed in making a new spring for the blade opening action I didn't take pictures of that procedure.... sorry.
What I did was cut a piece of a hacksaw blade and bent it to the shape I wanted. Then I heat treated it to put a spring in it. It works OK but the steel needs to be thicker to give the kind of action I would like to see.
SO here she is, out of the ER and in my collection of American auto-openers.

Thanks for looking everyone.

Mike

[doglegg]

M M, I like it when you rummage around in your old boxes. Fine job there.

[orvet]

Great rescue!

[glennbad]

Nice! I'm playing around with a Presto auto right now. Autos are fun and frustrating all at the same time.

[Meridian_Mike]

Nice! I'm playing around with a Presto auto right now. Autos are fun and frustrating all at the same time.

Well, I sure hope this thread helps you with yours. That is the reason I post stuff here. So I can get expert comments and to help others with their projects.
Yes, it sure is frustrating when parts are totally missing and you have to come up with the length and shape of that part.
I sat and looked at that liner for several minutes before I came up with a plan for the spring. I didn't have another one to look at so I just had to come up with the design on my own. I just wish that blade was a little thicker. I could have made a stronger spring.
Oh well, every time I get the opportunity to work on a knife I get a little more understanding under my belt. Sure is fun and sometimes rewarding!

Thanks for the comments everyone!

Mike

[Meridian_Mike]

Here is a very rough diagram of how I made the spring. I used the "cut-out" in the spine as an anchor point for the spring. I bent it to this basic shape.......and I put in an extra pin to capture the spring against the spine.

The length I show in the diagram is not necessarily correct. I had to make a second spring to get my length right. I made it so it engaged the blade at concave spot on the blade where it is shown in the second picture. Then as you close the blade, the spring rides up the concave part of the blade.

Sorry for the crummy pics....LOL. I should have taken pics before I put the liners back together....

Anyway Glenn, I hope this helps you with your Pronto.

Mike

[tinkerer]

Looks good!

If it helps, I ended up using a circular saw blade for the spring on the Edgemaster I re-did. I ended up checking several materials for thickness - sawzall blades, circular saw, and a piece of 16" Insulation Support Wire, the 3/32" wires that hold insulation between joists. All of these made decent springs for me.

[glennbad]

I'm not in my shop, or I would be able to take a pic for you. The normal spring that would go there looks something like this awesome artist rendering.

By having the spring made and installed this way, you don't have to put the extra catch pin to hold it in place.

Thanks for sharing your journey, it's always interesting to see how cleverly people are able to solve problems.

[Meridian_Mike]

Looks good!

If it helps, I ended up using a circular saw blade for the spring on the Edgemaster I re-did. I ended up checking several materials for thickness - sawzall blades, circular saw, and a piece of 16" Insulation Support Wire, the 3/32" wires that hold insulation between joists. All of these made decent springs for me.

Oh yes.... forgot all about those spring steel sources! Thanks for pointing those out.

Mike

[Meridian_Mike]

I'm not in my shop, or I would be able to take a pic for you. The normal spring that would go there looks something like this awesome artist rendering.

auto spring dwg.jpg


By having the spring made and installed this way, you don't have to put the extra catch pin to hold it in place.

Thanks for sharing your journey, it's always interesting to see how cleverly people are able to solve problems.

Ah ha!! Thanks for showing that spring design Glenn.... I will have to remember that. And after seeing your very nice sketch, I can see why I found no remnant of the original spring when I opened mine up. It must have broke right in the bend where the pin had it captured against the spine.
Good deal!

Mike