Started by limitdown, March 26, 2013, 02:33:49 PM
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Quote from: Tiddlerbasher on June 23, 2016, 08:26:15 AMI did a similar thing with an Okuma Andros - chrome steel (couldn't source SS) abec 7 AC bearings. Cost £120 per pair from GMN bearings.I can get similar results (from standard bearings) by backing the drag off to 10lb at strike - 20lb full. More than enough drag for a stand-up combo.
Quote from: captainmmm on September 30, 2016, 12:09:57 PMHi guys, has anyone found a place to purchase any Angular Contact bearings for the small Avets and Accurates ? I would be willing to commit to at least 100 pieces.
Quote from: limitdown on March 26, 2013, 02:33:49 PMAll of the comments that I received on my Avet 50EXW modification thread inspired me to modify my Makaira 50W. Although in its factory state, the Makaira 50W can put out more drag than I'll ever use or could possibly handle, I wanted this to be more of an experimental and exploratory modification which I want to eventually replicate for smaller reels that have serious handle binding issues even at low drag.As most lever drag owners know, the biggest problem is the axial load (side load) on two bearings. The pinion bearing (right side plate bearing) and the left spool bearing (the left side plate bearing if you have a "push" design drag like the EXW). The Makairas have a "pull design" drag so the left spool bearing shares the axial load with the pinion bearing.Although deep groove radial ball bearings can handle some axial load, they weren't designed for heavy axial loads. Also, if the radial bearings are small like in the small Avets, the amount of axial load capacity is pitiful and causes handle binding. The easy solution is to use a much larger radial bearing. Since most of us don't have CNC mills to machine new right side plates with larger slots for large radial bearings, we'll need to get a different type of bearing, one that can handle some radial load, and lots of axial load. The 3 types of bearings that I found during my research are:- Tapered roller bearings- Spherical roller thrust bearings - Angular contact bearingsOf these 3, only angular contact bearings are available off-the-shelf with inner diameters (ie bore) of less than 15mm. The world has "metricated" (ie moved to the metric system), so it's very difficult and expensive to find inch/imperial bearings. I haven't been able to find inch angular contact bearings for my EXW50 so I've put that project on ice. For small R4-sized bearings (0.25x0.625x0.196 inch) used in the small Avet SX, MX and JX's, angular contact bearings are either way too expensive at $125+ or need to be custom made at quantities over 500 pieces. If I can get 100 people to commit to purchasing 2 pieces each, then I'll commit the capital and take inventory risk. From my chats with a few bearing manufacturers, the best choice for our application would actually be tapered roller bearings, but they are much more difficult (ie expensive) to produce in small sizes.Luckily, the Makaira is all metric and correctly-sized off-the-shelf angular contact bearings can be found.Through a contact of mine in the machine parts business, I was able to squeeze in an order for some SKF 71900-sized angular contact bearings to replace the pinion bearing (10x22x6mm). For some reason, I didn't properly measure the left spool bearing when I serviced my reel a few months back. I figured that I'd just look at Alan's 50-Regular rebuild thread for the bearing size, 10x22x6. Nice, the same as the 71900. It turns that out the 50W's left spool bearing is 608-sized (8x22x7mm). I didn't realize this until I removed the left spool bearing and noticed that that the size wasn't right......So...I was only able to mount the 71900 to the right side plate. I just happened to have some full silicon nitride (Si3N4) bearings in 608 size left over from another project so I mounted one to the left side of the spool. I'm not sure what to expect from the Si3N4 bearing. The radial load rating is much higher than with 52100 bearing steel and 440C stainless steel, but I'm not sure how it would perform with axial load. Axial load rating of radial ball bearings is theoretically about 25% of static radial load, but I'm not sure if the Si3N4 balls are too brittle and will get crushed by the axial forces. I'll be doing some torture test and will let everyone know how this Si3N4 bearing holds up. I'll try to get a proper angular contact bearing for this soon.I haven't had time to do any pull tests with a scale, but my initial feel is that the handle is still very free-turning with the preset cranked down ridiculously and lever thrown to full.
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