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Mother of Pearl disassembly
Posted: Mon Jan 14, 2019 7:43 pm
by OLDE CUTLER
I was wondering if any of you knife mechanics would have any words of advice for dis assembling a shadow pattern mother of pearl pen? It is a 3" Boker that I picked up cheap at a gunshow. My normal method would be to take a Stanley box cutter blade and drive it down between the blades with a hammer to cut thru the 3 pins. I am thinking that that is too extreme for using on a MOP handled knife. The rocker pin on this pen does not go thru the handle material, and the rocker pin has pulled thru one of the liners and the spring side is opening up. I have never taken a MOP knife apart before and thought I may be able to get some tips to avoid breaking what is nice intact MOP. Another option I thought about is to use a tiny ball end cutter in the Dremel to remove the peened over ends from the pivot pins. Any words of wisdom from someone who has done this before?
Re: Mother of Pearl disassembly
Posted: Mon Jan 14, 2019 8:02 pm
by Doc B
I'm definitely no expert; however, I am a dentist and have started playing around, pulling apart knives. I've been taking apart the knives by drilling out the peened pin, as you mention. The trick is the bur wanting to chatter and jump around on the top of the pin.Not a problem with the cheap knives I've played with, to this point. Probably just have to be careful with the MOP (cutting the adjacent tooth is always bad business in my world). I usually only have to get a millimeter or two, of the pin removed, before the prying apart method can be done with less effort. I'd probably try removing it with a drill in a drill press (for stability) if you have that. I have some small diamond cylinder shaped burs...that are good for the job (end cutting like you've mentioned).
I have a drill press, a variable speed lab handpiece (like a dremel...but I can get it to go slower than the dremel). I also have a conventional dremel. I use all 3...but in my hands, the dremel would probably be my last choice. I'll be interested to hear what the people, who really know the answer, have to say. I like diamond burs like this...for this type of job.
https://www.amazon.com/SE-DT220R-Diamon ... 9427398784
Re: Mother of Pearl disassembly
Posted: Tue Jan 15, 2019 4:18 am
by btrwtr
Best I can say is be very careful whatever you do. I agree to grind off the heads of the pins but I tap them out with a punch. Either way be careful and go very slow. Sometimes you don't have to try very hard at all to crack the pearl.
Re: Mother of Pearl disassembly
Posted: Tue Jan 15, 2019 5:26 am
by Kolvir
Doc B wrote:I'm definitely no expert; however, I am a dentist and have started playing around, pulling apart knives.
I have often wondered if dentists were great at the various hobbies I do like modeling or repair jobs mentioned here that use dremel like tools.
Re: Mother of Pearl disassembly
Posted: Tue Jan 15, 2019 2:38 pm
by Doc B
Kolvir wrote:Doc B wrote:I'm definitely no expert; however, I am a dentist and have started playing around, pulling apart knives.
I have often wondered if dentists were great at the various hobbies I do like modeling or repair jobs mentioned here that use dremel like tools.
I can't say great...or even good...but I
have found a hobby, I can enjoy, after retirement...7 weeks and a day...if I was counting

Re: Mother of Pearl disassembly
Posted: Tue Jan 15, 2019 3:49 pm
by muskrat man
dremel off the head and try to tap out if it gives you trouble if you can at least get a gap between the handle and liner you can cut the pins with a jewelers saw
Re: Mother of Pearl disassembly
Posted: Tue Jan 15, 2019 4:42 pm
by OLDE CUTLER
Thanks for your words of wisdom gentlemen. I will go at it slowly and post pictures.
Re: Mother of Pearl disassembly
Posted: Wed Jan 16, 2019 5:04 pm
by orvet
Doc B wrote:I'm definitely no expert; however, I am a dentist and have started playing around, pulling apart knives. I've been taking apart the knives by drilling out the peened pin, as you mention. The trick is the bur wanting to chatter and jump around on the top of the pin.Not a problem with the cheap knives I've played with, to this point. Probably just have to be careful with the MOP (cutting the adjacent tooth is always bad business in my world). I usually only have to get a millimeter or two, of the pin removed, before the prying apart method can be done with less effort. I'd probably try removing it with a drill in a drill press (for stability) if you have that. I have some small diamond cylinder shaped burs...that are good for the job (end cutting like you've mentioned).
I have a drill press, a variable speed lab handpiece (like a dremel...but I can get it to go slower than the dremel). I also have a conventional dremel. I use all 3...but in my hands, the dremel would probably be my last choice. I'll be interested to hear what the people, who really know the answer, have to say. I like diamond burs like this...for this type of job.
Doc, welcome to the hobby that is more addictive the knife collecting!
I use very few diamond burs, I have a bunch but I have discovered that good carbide or even good high-speed steel burs cut better than the diamonds do. The trick is to find high quality burs. There is a jeweler's website called Otto Frei
http://www.ottofrei.com/ and they have quality burs, high-speed steel, carbide as well as diamond burs. They also sell Foredom flex shaft tools which are more like your dental drill, or at least like those I remember from my childhood; the long straight metal arms with articulating joints and the the belts that transferred power from one straight section to the next were made out of springs, or at least that's what they look like when I was a kid. They could grind so slow on your teeth that your head would vibrate. I thought that particular instrument was invented by some really perverted dungeon Master during the Spanish Inquisition!
I rarely use a Dremel tool myself, preferring instead the slower speed and higher torque of the Foredom. The slower speed and higher torque give you much more control over the bur. They also have a number of handpieces available, one handpiece uses collets, another uses a chuck. They even have one handpiece that is like a mini jackhammer. If you want to keep the burs from skating, I found one of the best ways to do that is to put the handpiece in my Foredom drill press and the knife in a knife makers vise and then I have control so the bur doesn't skate. The knife makers vise is available from Jantz supply. It's an expensive little piece, but it is well worth the expenditure.
Well, enjoy your last seven weeks in the dentistry profession. The one thing you cannot anticipate for retirement is how busy you will be. I know that seems counterintuitive but it's true. The first year I was really bored and I spent all winter making fishing lures in my garage shivering in the cold. The garage is now my shop and having been retired for 15 years in April, I tell you I have never been busier in my life. It doesn't seem like I ever get caught up or get the things done I need to do because there is always something more pressing like, surgery, naps, grandkid visits, naps, and by the end of the day I'm just worn out. Some days I have to take a nap before I go to bed I'm so tired! But I never get caught up anymore.

Re: Mother of Pearl disassembly
Posted: Thu Jan 17, 2019 2:19 am
by Doc B
orvet wrote:Doc B wrote:I'm definitely no expert; however, I am a dentist and have started playing around, pulling apart knives. I've been taking apart the knives by drilling out the peened pin, as you mention. The trick is the bur wanting to chatter and jump around on the top of the pin.Not a problem with the cheap knives I've played with, to this point. Probably just have to be careful with the MOP (cutting the adjacent tooth is always bad business in my world). I usually only have to get a millimeter or two, of the pin removed, before the prying apart method can be done with less effort. I'd probably try removing it with a drill in a drill press (for stability) if you have that. I have some small diamond cylinder shaped burs...that are good for the job (end cutting like you've mentioned).
I have a drill press, a variable speed lab handpiece (like a dremel...but I can get it to go slower than the dremel). I also have a conventional dremel. I use all 3...but in my hands, the dremel would probably be my last choice. I'll be interested to hear what the people, who really know the answer, have to say. I like diamond burs like this...for this type of job.
Doc, welcome to the hobby that is more addictive the knife collecting!
I use very few diamond burs, I have a bunch but I have discovered that good carbide or even good high-speed steel burs cut better than the diamonds do. The trick is to find high quality burs. There is a jeweler's website called Otto Frei
http://www.ottofrei.com/ and they have quality burs, high-speed steel, carbide as well as diamond burs. They also sell Foredom flex shaft tools which are more like your dental drill, or at least like those I remember from my childhood; the long straight metal arms with articulating joints and the the belts that transferred power from one straight section to the next were made out of springs, or at least that's what they look like when I was a kid. They could grind so slow on your teeth that your head would vibrate. I thought that particular instrument was invented by some really perverted dungeon Master during the Spanish Inquisition!
I rarely use a Dremel tool myself, preferring instead the slower speed and higher torque of the Foredom. The slower speed and higher torque give you much more control over the bur. They also have a number of handpieces available, one handpiece uses collets, another uses a chuck. They even have one handpiece that is like a mini jackhammer. If you want to keep the burs from skating, I found one of the best ways to do that is to put the handpiece in my Foredom drill press and the knife in a knife makers vise and then I have control so the bur doesn't skate. The knife makers vise is available from Jantz supply. It's an expensive little piece, but it is well worth the expenditure.
Well, enjoy your last seven weeks in the dentistry profession. The one thing you cannot anticipate for retirement is how busy you will be. I know that seems counterintuitive but it's true. The first year I was really bored and I spent all winter making fishing lures in my garage shivering in the cold. The garage is now my shop and having been retired for 15 years in April, I tell you I have never been busier in my life. It doesn't seem like I ever get caught up or get the things done I need to do because there is always something more pressing like, surgery, naps, grandkid visits, naps, and by the end of the day I'm just worn out. Some days I have to take a nap before I go to bed I'm so tired! But I never get caught up anymore.

Dale, the Foredom drill looks like a good one. I, too remember the flex shaft drills and have used them in the lab, many years ago. Fortunately I didn't have to use them on a patient. I have part of the old patient ones...in my living room...will have to post a picture (I'm down at the ranch, now).
I too, mostly use carbide and steel burs, in a relatively cheap dental lab handpiece ...that uses conventional dental burs. I don't use diamond burs very much, either. In my very limited experience with removing pins, it's been my observation, that if I can remove 1-2mm, of the pin...it undermines the peening enough, to tap the pin out. I'm pretty confident, I could cut a pin out, with a carbide bur. 1/10 of a millimeter is a distance I work with daily; I know I could stay away from cutting the MOP. I figure, if you don't routinely cut pins out, with a drill... a diamond bur would be easier to control...and avoid the MOP. As you said...slow and torque, gives much better control. I picked this relatively cheap Chinese lab drill up...that so far, is holding up pretty well. It has a variable speed control and a foot pedal. We will see how long this one lasts.
https://www.ebay.com/itm/Dental-Lab-Mar ... :rk:3:pf:0
Re: Mother of Pearl disassembly
Posted: Wed Jan 23, 2019 12:20 am
by Bill DeShivs
Something many don't realize, is they make variable speed Dremels.
You can also use a foot rheostat with a Dremel- it becomes a variable speed tool.
You can also use a rheostat with the variable speed Dremel for even more control.
Re: Mother of Pearl disassembly
Posted: Thu Jan 24, 2019 7:49 pm
by OLDE CUTLER
What I ended up doing with this Boker pen to disassemble it was to use a tiny ball end cutter in the Dremel tool and make a tiny dimple in the center of the pins and then gradually work that out to the edges to take off the peened over end to the pins. Then they pushed right out. Cleaned everything up and reassembled by countersinking the outside of the liners over the rocker pin, put in new rocker pin, filed everything flat and reassembled the pivot pins. Turn out good, I was VERY CAREFUL when peening the pivot pins. Like I said, this was the first MOP knife I have had apart.
Re: Mother of Pearl disassembly
Posted: Thu Jan 24, 2019 7:55 pm
by tinkerer
That came out nice.
Re: Mother of Pearl disassembly
Posted: Thu Jan 24, 2019 8:12 pm
by Twhite
great job.

Re: Mother of Pearl disassembly
Posted: Thu Jan 24, 2019 9:10 pm
by #goldpan
Wow! Very cool.

Re: Mother of Pearl disassembly
Posted: Thu Jan 24, 2019 10:30 pm
by doglegg
OH that one turned out great.

Re: Mother of Pearl disassembly
Posted: Fri Jan 25, 2019 3:48 am
by btrwtr
Well done!
Re: Mother of Pearl disassembly
Posted: Fri Jan 25, 2019 11:52 am
by Doc B
She's a beauty! Nice job on the blades, too...they were in need of some OC love, got it and came out great!
Re: Mother of Pearl disassembly
Posted: Sat Jan 26, 2019 9:44 pm
by orvet
Very nice work. Looks like it's ready for the pocket
