Folder blade alignment Question.

blackhawkcowboy

blackhawkcowboy

Joined
Sep 11, 2012
Messages
36
I've made two folders so far. The problem I'm having is that my blade rubs on one side when I close it. I have taken extra care to drill all the pivot holes straight. I did order the steel oversized and not precision ground. So I have to grind the flat sides to remove the surface, also to get it to a size that is manageable. I do know that I probably need a surface grinder but I don't have one. It's not warpage from the heat treating, I'm pretty sure it's the grinding.

I guess what I'm asking is, should I just buy the precision ground steel or is there any tricks or tips or maybe something that I'm missing on getting the alignment right?
 
What kind of folder are you making? With a liner or frame lock, if you are SURE the pivot hole is straight, and if your blade is of an even thickness and flat (checked with a micrometer or good calipers) then I would suspect that your backspacer is not the right thickness. Which would be, the thickness of your blade plus the thickness of your washers. A surface grinder is nice, but not necessary. I've done OK just grinding as close to flat as possible with a sharp belt over the platen, holding the blade with a big speaker magnet. Then lap with paper on granite or glass.

All other folders are outside of my experience.
 
Once everything else is perfect, if it's still a little off-centered, try loosening the pivot hardware, as well as any hardware near the pivot. Then take a small folded piece of paper and lodge it between the blade and liner. Make it so that the blade is slightly over-corrected, then tighten up the hardware and remove the paper. You may have to fiddle with it a couple of times.
 
As Salem says, having the backspacer less than perfect is a pretty common cause of this that isn't easy to spot.
I got pretty frustrated at one point learning how to do folders because I felt I was doing everything right and still not getting the blade centered.
After a sort of a ctrl/alt/del reset that involved just getting EVERYTHING flat, true, and parallel, I realized that some of my backspacers were tweaky, and that pulled the liners to one side, and that made the blade rub.
Course, there's a number of other things that will pull the blade off center: pivot holes not aligned, crooked hole through blade, blade not perfectly ground, spring pushing the blade to one side, play in the bushings...oh, and a full flat grind is less likely to show that, for obvious reasons..
 
Salem Straub said:
What kind of folder are you making? With a liner or frame lock, if you are SURE the pivot hole is straight, and if your blade is of an even thickness and flat (checked with a micrometer or good calipers) then I would suspect that your backspacer is not the right thickness. Which would be, the thickness of your blade plus the thickness of your washers. A surface grinder is nice, but not necessary. I've done OK just grinding as close to flat as possible with a sharp belt over the platen, holding the blade with a big speaker magnet. Then lap with paper on granite or glass.

All other folders are outside of my experience.
Click to expand...

Wow! Thanks so much for the advice. Hate to say but one of the few things I didn't check was the size of the back spacer compared to the blade thickness and washers. (which seems so obvious now) That very well could be one of my issues.

Fixed blades are on thing, Folders are a whole other animal I'm coming to find out;)

The type of knife is a Frame Lock with a liner and G10 scales for the other side.
 
blackhawkcowboy said:
I'm as sure as I know how to check. Do you have any ways to check?

I'm in the Army so I only do this as a hobby and with the tools I can move with me every three years..:D

By the way Love the Hebrews quote..
Click to expand...

I assume you're using a drill press? In that case, I'd use a dial indicator to make sure my table was as square as I could make it to the quill.

Also, keep in mind that any grinding after drilling and heat treat can affect things, as well as if your steel isn't flat and parallel to begin with.

Good luck, and thanks for your service.
 
If you are using a drill press and do not have a dial indicator, you can still check your table to chuck angle.
Take some welding rod or other stiff wire and bend it into a sort of Z shape with long ends. Chuck one end up. Start the press on low speed, and slowly feed the quill down until the bent rod begins making contact with the press table. It should pretty much rub in a full circle from first contact. If not, the area it hits first is of course high, and you adjust your table accordingly.

Your table may however test true and yet be flexing out of true under drilling pressure. I have a small press that does this unless a sharp bit and minimal pressure are used. Drilling slightly undersize and then reaming to exact with light pressure helps with this.
 
Thanks Gunfight and Salem, These are things I never did think about, and also wouldn't know how to check... I also was using a vise with my drill press which sat on top of the table. I have recently found one of the vises that will pin the piece to the table. I'm hoping that will help as well. I'll be ordering some reamers today, I wasn't sure what to use them for but now having to dill with precision and counter bores I can see why.
Well I guess I've got a lot more to learn.;) Thanks again for all the help.
 
Salem Straub said:
If you are using a drill press and do not have a dial indicator, you can still check your table to chuck angle.
Take some welding rod or other stiff wire and bend it into a sort of Z shape with long ends. Chuck one end up. Start the press on low speed, and slowly feed the quill down until the bent rod begins making contact with the press table. It should pretty much rub in a full circle from first contact. If not, the area it hits first is of course high, and you adjust your table accordingly.

Your table may however test true and yet be flexing out of true under drilling pressure. I have a small press that does this unless a sharp bit and minimal pressure are used. Drilling slightly undersize and then reaming to exact with light pressure helps with this.
Click to expand...

That's a very clever way of checking squareness...
 
I assume that the blade rubs opposite the frame, lock side of the knife. This is due to the tension of the lock pushing the blade over. This can be partly due to the blade hole being over sized so there is excessive play at the pivot. a half thousands at the pivot will translate into a bunch of movement at the tip. another thing that can cause the tip to ride over is the frame lock pushing the whole handle out of square. This happens when the knife is screwed together with the blade closed. This is assuming that the pivot hole is square and the blade sides are flat and parallel at the tang and that the pivot you are using is round.
 
Bill Burke said:
I assume that the blade rubs opposite the frame, lock side of the knife. This is due to the tension of the lock pushing the blade over. This can be partly due to the blade hole being over sized so there is excessive play at the pivot. a half thousands at the pivot will translate into a bunch of movement at the tip. another thing that can cause the tip to ride over is the frame lock pushing the whole handle out of square. This happens when the knife is screwed together with the blade closed. This is assuming that the pivot hole is square and the blade sides are flat and parallel at the tang and that the pivot you are using is round.
Click to expand...

It does rube the opposite side of the frame, but it does this before I even cut the lock out or bend it. I have notice that my pivot hole could stand to be a little tighter.

One of the other things that I just notice was that my counter bore holes are not centered as well as they could be. I've ordered some reamers to help with this problem. The counter bore that I use has a smaller pilot than the 3/16" pivot hole that I need. So I drill the hole for the pilot first then after I've drilled the counter bore I come back with the 3/16" drill bit. (I'm sure this isn't the best way to do this) I have noticed that it's almost impossible to keep that center hole lined up. By the way can you get a 3/16" Pilot on a counter bore? or would that risk the tolerance to much?

I've really got to slow down and take my time, also can't wait for this winter to pass so I can get out there more. I'm sure it's funny having to go over things you guys have probably surpassed long ago, but I really appreciate it..:D
 
blackhawkcowboy said:
It does rube the opposite side of the frame, but it does this before I even cut the lock out or bend it.
Click to expand...

In that case, it is a pretty sure bet that the pivot hole is not perpendicular to the flats of the tang. I have always found that drilling my pivot hole undersized and then reaming to final diameter gave me better results than just drilling the hole.
 
You must log in or register to reply here.
Back
Top