When to finish the profile

[Don Robinson]

I've noticed for a long time that when I see a WIP thread with someone else's work in a photo that the individual parts of a folder are nearly always profiled before assembly.

I never do that, and I believe you are better off profiling the outside of the blade and handle after trial assembly.

I finish matching pieces one part as a time as I make the knife.

For instance, on a slipjoint:

Rough out the blade, then finish the tang, then the matching end of the spring where it fits the tang, then the inside of the spring to match the closed blade.

Then do all the pins and locations.

Leave the liners saw cut and oversize.

Assemble the knife. Don't move the blade in any position. That could damage the soft spring.

First put it together with the blade open. Then profile the back of the blade, spring and liners .

Next, take it apart and assemble with the blade closed. Profile the blade end of the liners.

Reassemble with blade open and profile the belly of the liners.

Now, after setting the rise and fall just right, HT the blade and spring, put it all together again and finish profiling all over.

If you finish the profile to size on each part before trial assemblies you're going to find that your parts don't fit correctly.

[TexasJack]

Always love to see lessons from the experts! Thanks for the post, Don!

[Crockett]

Don I?ve come back to your post here several times and reread it. What you are saying makes a lot of sense and I?m trying to visualize how to incorporate your advise into my ?way.? I think I am probably creating extra work for myself and not being as efficient as I could. The process I have developed works for me, my unique way of thinking and it also compensates for a few problems or lack of understanding I have with building slip joints.

One of the issues I have is with setting the rise and fall. I spent a lot of time building a rise-and-fall setting fixture like the ones discussed and pictured here and elsewhere on the net. I set my rise and fall to within .001? in the open and closed position on the fixture. Then when I put the knife together, it?s different. I?ll have an unacceptable difference between the open and closed position of the spring and I have to refit my blade tang to correct the difference. In a few cases I?ve wound up with a knife I couldn?t finish because I ended up with not enough material left on the tang for proper operation. I?ve given up on trying to figure out what I?m doing wrong, and just adapted my way of building to compensate.

I would love to spend some time learning from a more accomplished maker rather than reinventing the wheel! I know there?s a better way. But alas, resources are limited?time, money, wife?s patience?

Thank you for posting your advice!

Don

[DaveL]

As always, love your stuff Don. Yeah, I still think that slipjoint "how to" by you is long overdue

[Don Robinson]

Originally Posted by Crockett

Don I?ve come back to your post here several times and reread it. What you are saying makes a lot of sense and I?m trying to visualize how to incorporate your advise into my ?way.? I think I am probably creating extra work for myself and not being as efficient as I could. The process I have developed works for me, my unique way of thinking and it also compensates for a few problems or lack of understanding I have with building slip joints.

One of the issues I have is with setting the rise and fall. I spent a lot of time building a rise-and-fall setting fixture like the ones discussed and pictured here and elsewhere on the net. I set my rise and fall to within .001? in the open and closed position on the fixture. Then when I put the knife together, it?s different. I?ll have an unacceptable difference between the open and closed position of the spring and I have to refit my blade tang to correct the difference. In a few cases I?ve wound up with a knife I couldn?t finish because I ended up with not enough material left on the tang for proper operation. I?ve given up on trying to figure out what I?m doing wrong, and just adapted my way of building to compensate.

I would love to spend some time learning from a more accomplished maker rather than reinventing the wheel! I know there?s a better way. But alas, resources are limited?time, money, wife?s patience?

Thank you for posting your advice!

Don

Don, I realize that what I said is hard to understand. That's the best I could come up with without a show and tell.

All it boils down to is : Don't finish any part until you get ready to fit it to its mating part.

As far as setting your rise and fall, I can't say what went wrong. Maybe the way you use the fixture?

[Don Robinson]

Don Crockett, have you seen my fixture in use in the toothpick thread sticky? Does yours look like mine?

[Crockett]

Originally Posted by Don Robinson

Don Crockett, have you seen my fixture in use in the toothpick thread sticky? Does yours look like mine?

Yes very much so. Yours was one I modeled mine after. I think my problem has to do with the fact that the height of the spring center pin relative to the blade pivot is a little different on the gage vs. the knife...but I think unless you have one gage dedicated to one knife pattern, it's going to work out that way regardless?

I think what compounds my problem is my blade tang geometry. I don't know if I should try to explain it further, I might make it pretty confusing...

Crockett

edit; I just thought this all through, and even made a CAD drawing and manipulated it, changing the height of the spring center pin to the blade pivot, both blade open and closed. In my mind as well as on the CAD model, I don't see how it can make any difference, the rise and fall should not change, once set correctly. But for me, when I make a real knife, it does. I don't get it.

[Don Robinson]

How much does it change?

Does your fixture hold the blade and spring approx. level, considering you want the blade tipped down slightly?

I set the blade/spring relation on the fixture like I want the finished knife to look.

You can always drill more holes in the slide to change the relationship. There should be room for lots of pin holes in the slide.

After HT the spring is always loaded, causing it to bend (hump) upward just a little between the center pin and tang makeup. That makes it necessary to gently refinish the back of the knife at final assembly.

[Crockett]

I set it up on the gage pretty much like I intend it to be when finished. I?ll set open and closed positions so the top of the spring just above the pivot is within .001? in both positions. Then when I assemble my knife after HT and load the spring I?ll have the spring like .008? or .010? higher in the closed position than open. Not a lot but enough to be painfully obvious. And of course if I grind it flush open then it?s too low closed by that same amount. I?ve had this happen three times in a row (three different blade/spring combos) and fixing the discrepancy involved fitting the tang and adjusting rise/fall the same way I was doing it before I made the gage?so I just quit using the gage! But man it sure confuses the heck out of me!

[Don Robinson]

When I'm setting the R&F and I get to setting it with the blade closed, I push the rear of the spring upward hard with my left hand to make sure the spring is under tension and watch the indicator gage.

I also apply hand pressure in the other two positions. Could this be the problem?

[Crockett]

Could be although I tried to keep even pressure at all times. I may not have been consistent. I won't be working on any knives for a little while but when I do I'll see if I can sort it out.
Don

[Don Robinson]

Originally Posted by Crockett

Don I?ve come back to your post here several times and reread it. What you are saying makes a lot of sense and I?m trying to visualize how to incorporate your advise into my ?way.?

Don

If you look at the photos in "My Way" you'll see that I followed what I've said. Nothing is finished to exact shape until assembly.