Help please, pins won't fit hardened blade pin holes

J

johnfbkennedyy

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Feb 22, 2021
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Hi all, I would greatly appreciate any help on this matter. So I'm new to knife making and I thought I'd start by buying blades and constructing my own kit. I bought 1/4 mosaic pins, 1/8 pins and 3/32 from USA Knifemaker. I also bought these two blades with respective pin hole sizes from alabama damascus but they wont fit. These blades are already hardened, is there anything I can do? I don't have many tools, so no drill press but I have a drill and dremel if that is of any use. Some people have suggested me to file down the pin holes, others have suggested me to sand down the pins. I'm not sure what is the best option.
t4VIRUS

Thanks in advance
 
I linked your image below, you have to use the image address, not the url of the imgur post.

Make sure there is no burr at the end of the pins from cutting. A file should take care of that.

Keep in mind that the pins do not only have to get through the holes in the tang of the blade, but the handle scales as well. You will want to use the blade as a guide for drilling the holes in the scales, so you have to have a drill bit that is smaller than the hole in the tang but large enough for the pins to slide in easily. There are many ways to get there, it just depends on what tools you have and/or what you are willing to buy. I do not think the fit through the hole in the tang is critical and nobody will ever see it. The fit in the scales is more important since it will be visible, so I would start there. I normally use a drill bit that is a few thou larger than the pin diameter, say a letter F drill bit for a 1/4" pin. I have also chucked pins in a drill and used sandpaper or the grinder to make them fit. My recommendation is to drill some test holes in scrap material and figure out how to make the pins go through those easily. Then open up the holes in the blade to accommodate the drill bit. The rotary tool like B bdmicarta suggests is probably your best bet for that, you are almost guaranteed to snap carbide drill bits with a handheld drill.

After you get your scales drilled, do a dry fit before glue up. The pins should go in easily and you should not have to use a hammer. This can be tricky, especially if you drill your holes with a handheld drill. The larger blade is probably easier, I would start with that one.

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I semi-oversize my blade tang holes by a # drill size or two pre ht. They're just there to let the pin slide through and can really only hurt you by being too tight. Scales, imho should be a bit of a slip fit but obviously not oversized enough to create a visible ring. If a mosaic pin this may need to be a bit tighter on the scales as people tend to not peen those. Otherwise peening should take care of any tiny gaps and really be the thing holding the scales on in the end. I consider glue to be more for sealing and keeping moisture out than relying on it being a pure method of attachment. Cheap man's solution here is to chuck up some sandpaper wrapped around a pin and spin it in the hole with a drill. If its just tiny variances from HT it wont be much to take off.

I don't recall using pins I didn't have to sand down a bit to slip fit a hole "the same size." You'll wand to do that anyways to give any glue a bit more to grab onto vs the slick surface pins come with. Chuck the pin up in a drillpress/drill and wrap it in a piece of sandpaper and you'll be done fast.
 
When this happens, just move up to the next bit size and drill it again. The epoxy will fill in around your pins so it won’t hurt anything.
 
Or cheap masonry bits in your hand held drill. They wobble a little bit so are perfect for making a slightly smaller hole larger. If ya have a 1/8" pin that doesn't quite go in a 1/8 inch hole use a 1/8" bit. Little drop of oil and it wobble right on through and then your pins will fit.
 
Mosaic pins are expensive, so unless you have your heart dead set on them, you could always change your pins to solid brass, or aluminum and save the mosaic pins for a future project. Aluminum and brass pins are very easy to sand down, and over sanding won’t alter their appearance.
 
Thanks to all for the amazing input! I did go with the idea of sanding down the pins. Worked great, I think I sanded to much off since they now wobble too much but since I'm using epoxy to apply them, I think this won't be a problem?

Thanks
 
johnfbkennedyy said:
Thanks to all for the amazing input! I did go with the idea of sanding down the pins. Worked great, I think I sanded to much off since they now wobble too much but since I'm using epoxy to apply them, I think this won't be a problem?

Thanks
Click to expand...
I would start again and shoot for a snug fit.
A ring around the pins might bother you depending on how good the rest of the fit and finish is.
You could decide just to finish it up and improve more things next time.
 
The pin can be a little loose in the tang, but the scales need to be close fit, just enough for the pin to slide without resorting to a hammer. Epoxy can fill that interior space and still retain the strength. Since you sanded the pins small, now you have to be cautious about drilling the scales. It is a good idea to get a drill bit gage and try to find the diameter that works best, with just the right amount of free play so you select the proper bit size. You may find you need metric or even the alphabetical sized bits.
 
If the pins are 1/8” then head to ge hardware store and buy a carbide burr that’s 1/8” for a dremmel tool. Chuck it up in the drill press and drill out the pin holes. There is a good chance the Alabama Damascus is not very hard anyway.
 
#30 drill bit for a 1/8" pin. F for a 1/4", #12 for a 3/16" pin. Gives a clearance hole so the pin slides in easily, but leave a touch of room for epoxy. I used to chuck the pin in a drill press and use a file to make it fit the holes or use a dremel burr before I found the clearance drill size. I usually get a carbide 5/32" bit for drilling 1/8" pin holes in hardened steel, but a Masonry drill bit should work for those blades as well.
 
Carbide reamers are a wise investment. Pick a size that is about .005" over the pin size. You can buy reamers on ebay cheap when industrial shops get rid of them because they are out of specs.

It may have already been mentioned already, but the biggest issue with drilling wood handles for pins is that the wood fibers get compressed by the drill as it cuts through them and then springs back after the drill is removed. This makes a hole smaller than the bit that drilled it. This is why the normal recommendations for #30, F, #12, etc. Stabilized woods drill cleaner than non-stabilized. Oily woods have the most spring-back. It is a good idea to check the pins fit about 30 minutres after drilling to see if the holes need to be re-drilled or reamed.

TIP:
Drilling the tang with the same size bit as the pin is almost always going to cause problems. Drill tang holes oversize by a good amount. I recommend 15% to 25% oversize. Doing this will prevent the problems we see on FIF and read about in Shop Talk where one or more pins will not going through the handle. The excess space gets filed with epoxy and is not an issue.
 
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