RandyR
KNIFE MAKER
Since I am down a bit due to double hernia surgery, I thought I would share my perspective and approach for pinning bolsters on full tang blades. I have read a lot of posts that state you should drill holes larger than the pin stock to ensure the pins will actually go in. Good advice but it can cause some side-to-side alignment issues when you hammer or press the pins in. Even a slight shift between the two parts will show in the finished knife. Here is my approach to obtaining the best alignment posssible between the sides.
First, I always use at least three holes, four if the design will allow, to improve positional stability. I almost exclusively use 416 stainless and 3/32 pins. Now comes the interesting part. I drill and ream the holes using a #42 bit and reamer which is slightly smaller than the pin diameter. Most pin stock is cold finished with a pretty rough surface and if heat treated it can be a bit rougher. To help the pins vanish, it is necessary to clean all the contamination off until you have a clean surface or you could see a ring around the pins. I just use small pieces of 220 grit paper and hand sand the outside clean. Usually, when the pin is truly clean, it will now fit with a minimum of clearance in my holes. Sometimes a bit more sanding is needed but, in any case, it only takes a few minutes. With the three or more low clearance holes, the bolsters are not inclined to move when the pins are set by whatever means. Obviolusly, you need to have good perpendicularity between the holes and all the parts but a properly set up drill press will do that. I taper ream the holes as others do and use my home built press to squeeze them in.
I have done a lot of bolsters this way and have rarely had any visible side-to-side alignment issues. It is a bit more work but it can save having to drill out pins and make new bolsters when things don't go as you would like.
I hope this is of value.
Randy
First, I always use at least three holes, four if the design will allow, to improve positional stability. I almost exclusively use 416 stainless and 3/32 pins. Now comes the interesting part. I drill and ream the holes using a #42 bit and reamer which is slightly smaller than the pin diameter. Most pin stock is cold finished with a pretty rough surface and if heat treated it can be a bit rougher. To help the pins vanish, it is necessary to clean all the contamination off until you have a clean surface or you could see a ring around the pins. I just use small pieces of 220 grit paper and hand sand the outside clean. Usually, when the pin is truly clean, it will now fit with a minimum of clearance in my holes. Sometimes a bit more sanding is needed but, in any case, it only takes a few minutes. With the three or more low clearance holes, the bolsters are not inclined to move when the pins are set by whatever means. Obviolusly, you need to have good perpendicularity between the holes and all the parts but a properly set up drill press will do that. I taper ream the holes as others do and use my home built press to squeeze them in.
I have done a lot of bolsters this way and have rarely had any visible side-to-side alignment issues. It is a bit more work but it can save having to drill out pins and make new bolsters when things don't go as you would like.
I hope this is of value.
Randy
