Hey guys.... I have this crazy idea of putting some type of shaft slide bearings (that have ball bearings on the inside diameter) permanently into my paddles. This way there would be zero play, especially w/ the new joint on the upgrade arms. I know it would cost some, but I think it would be cool and be a nice thing to offer... I know you have played around w/ this come Clay, with putting a bronze bushing (without bearings) inside the top and bottom of your paddles but didnt' think it was worth it. Well what about something like below, in a version that's not as elongated? They would just "roll" up and down the arms as you sharpen... don't know if diamond dust/abrasive would be an issue though. Anyway, does anyone know of any resources or what something like this in a smaller version would be called?

Wow, that would be awesome. I don't have any ideas of where to start looking, but if anyone has a lead, I'll follow it.

That would be a great idea but the only problem is that those linear motion bearings come with a round cardboard tube in them,you slide the tube out as your putting the bearing on the shaft and if you pull that bearing off the shaft all the balls fall out. I work maintenance for a big corporation and deal with a lot of those bearings and they can be a giant pain to work with.

Interesting idea, but Clay and others claim, that play in the old arms is not issue (old arms produce equally great edge like the new ones with much smaller play), so I think it isn't worth increased cost and maintenance.

Bart LaMont wrote:


Bart, do you have any idea of whether they make bearings like we would need for our purposes? I just have no idea where to start... guess you wouldn't actually need bearings and could just use bronze bushings... I am targeting to reach zero play =)

LukasPop wrote:


Oh, you can get great results the way they are! I don't have any play in the joints themselves since I have modded them w/ screws... I am having some variance from the ID of the paddles and the OD of the rod arms, and that's what I am targeting. This is resulting from a knife I sharpened over the week that I noticed 2 different bevels... not a large difference, but it was definitly noticeable. See, you have to hold the paddle a certain way to maintain consistency... I believe I remember you saying Clay that you put pressure on the bottom of the paddle while sharpening with the palm/heel of your hand, correct?

What I noticed was when you use Clay's technique, and then alter it and put pressure at the top instead and pull the bottom out (as others have done/shown on youtube) then it creates a slightly steeper bevel.

This isn't really an issue if you do it consistantly, but when you are going for speed (professional sharpening, where time is money) but yet you still want to hand sharpen, then it creates an issue. This is because it takes much more time to slow down and focus on holding the paddle properly, whereas if you had the bearings/bushings, it would be very quick.

I'm not sure about a bearing but like you said a bushing, does not have to be bronze you could go with a plastic type bushing. You could find any machine shop or even a gunsmith to make a couple custom bushings for you to try out.

Ok Josh, it sounds reasonable

razoredgeknives wrote:


Have you seen this more than once? Just curious... I had this happen once on a knife, and could never figure out why. My technique was consistent, the knife was stable, etc. But in the end I had 2 distinct bevels. I redid it and couldn't even duplicate the issue... I finally concluded that I maybe didn't get the arm "seated" in the indent in the arm bar, and it moved just enough to cause this, (although in thinking about it now, I'm not even sure that would be enough to cause it).

If you're seeing it more than once then it could be something else, but a one time event, maybe not? Just something to consider.

Well, I admit that I wasn't holding the paddles consistently.... For all of the first stones I just held it like "normal", not putting pressure on any certain spot of the paddles, and sharpened away up until I got to the 1k grit stones. Up until tho time I had been doing sweeping passes from heel to tip. But I like to finish my edges in the opposite direction (from tip to heel), so I kept my weps in the same position but started performing edge leading passes from heel to tip, this time holding the paddle with the bottom held out and the top pushed in with my index finger. This created two slightly different bevels.

I noticed that you can rest your Palm on the bottom of the paddle and then reverse it to where you press your index finger at the tip, and this does the same thing. I'm just saying that it would be nice to "fix" this for those of us who want to just "hammer away" and not have any consistency issues.

The picture is of linear ball bearings. Sometimes they are called "circulating ball bearings" because the balls roll around in a closed loop. You can find them in many places, including McMaster.com.

For example:
www.mcmaster.com/#linear-bearings/=lrc0y9

Machinist and author Tom Lipton wrote that one should read through the entire McMaster catalog. "Yes, read it," he said. I certainly have learned a lot from just browsing through it. If you are a mechanical designer or hobbyist-maker, I very much recommend browsing McMaster's catalog, as well as other catalogs.

btw, if you care, Tom Lipton's book is here:
www.amazon.com/Metalworking-Sink-Swim-Ma...s+%22Sink+or+Swim%22

Keep in mind there are a zillion different types of bearings for a zillion different applications and they have different levels of precision and robustness etc.

Sincerely,
--Lagrangian

P.S. McMaster.com doesn't always have the best prices, but their catalog is huge and full of information. So it's good to browse, but probably worth comparison shopping once you know which specific part you want.