Maybe because we are all reel nerds/enthusiasts but seems to me that Penn spinning knobs seem to be in short supply. The knobs for 704,714, 716, 420ss,430ss are always bid up if you can get them. For example i have been waiting for either black or white 720/722 knobs to appear on ebay. What we get are cracked knobs that require regluing etc. seems to me that old penn molds or some CNC master or 3D printer make them. Thoughts and comments?
Yeah! I think it would be great. Several recent 714z & 716Z knobs were listed and described as cracked. I couldn't believe it. At the going rate for new/not cracked knobs, that's half the cost of a decent used reel.
I've designed and 3D printed 720/722 knobs. It isn't too hard, but you have to also fabricate and/or salvage some of the metal bits.
Most folk here want something prettier than what comes out of most 3D printers, but the parts are strong enough for the smaller reels.
There are some techniques to post-process the prints to smooth out the print layer lines for some plastics, but too much work for doing a bunch.
-J
Couple of points: they are extremely popular reels, and this is a common issue. Reason most likely being the interface between the metal (threaded) insert and the plastic knob. I'm not sure that trying to reproduce something like that today would have much better results in the long term - maybe a machined all metal knob, but now you are getting into some serious expense. - john
A machined delrin blank into which you would epoxy your threaded metal insert would be perfect. This would work great on the reels that use a large diameter spring washer under the flat-bottomed knob (716, 714, 420/4200ss, 430/4300ss). On the reels that have springs and other whatnot built into that little raised nub, replacements would be trickier. I suppose a solid machined knob with no springs etc could work, and it would be better than no knob.
I thought I'd have a few of these in the stash. Turns out I do not, other than a small handful of the more modern "power drag" variety, and I'm not even sure which reels they're for. So almost useless there on my end.
A solid cap and a light bellville might be a functional replacement.
I do have a ton of new 706z and a handful of 704z replacement emblems though if anyone needs them. Not sure that advances the discussion though.
I'd be happy to make these drag knobs for you guys, but I don't know how competitive I'll be pricewise. Please PM me if you have any cracked or broken knobs that I can reverse engineer. I'm already working on a 720/722 knob that someone has asked for.
Quote from: Fishgolfman on May 11, 2023, 01:59:36 AMMaybe because we are all reel nerds/enthusiasts but seems to me that Penn spinning knobs seem to be in short supply. The knobs for 704,714, 716, 420ss,430ss are always bid up if you can get them. For example i have been waiting for either black or white 720/722 knobs to appear on ebay. What we get are cracked knobs that require regluing etc. seems to me that old penn molds or some CNC master or 3D printer make them. Thoughts and comments?
How about a donation made to Alan's charity https://discoverangling.com/calendar
And I will send you a brand new black knob? Maybe even toss in a mating 714Z spool too :)
tony
While fishing remotely in another country...when knob broke .. guide resorted to a wing nut!! Ugly looking reel but worked till I was back in USA
Quote from: Brewcrafter on May 11, 2023, 08:08:57 AMCouple of points: they are extremely popular reels, and this is a common issue. Reason most likely being the interface between the metal (threaded) insert and the plastic knob. I'm not sure that trying to reproduce something like that today would have much better results in the long term - maybe a machined all metal knob, but now you are getting into some serious expense. - john
Not an expert, but I did get some rudimentary injection molding training. I think it works like this:
Unless the part is simply not strong enough, the reason that these cracks occur over time is internal stress locked in the plastic from the part shrinking unevenly while cooling during the molding process. Areas with thinner diameter, tight radius bends, molding around metal inserts, etc. As the part ages and loses plasticity, the stresses are stronger the the internal bonds, and the cracks appear
Press fitting metal parts into plastic after molding also introduces stresses. The problem with inserts is if they can be pressed in, they can pop out, so it is always a balancing act: the higher the interference on the fit, the less likely the insert will pop out, but greater odds of getting stress cracks over time, and the opposite if you go for a low interference fit. I hate hate hate blind press-in inserts into plastic parts, but manufacturers with fancy equipment can do better work with modern inserts.
Machined plastic like Delrin or one of the higher tech plastics can be plenty strong with the right design, but it can be a pain in the *ss to get a polished finish. Plus on the bigger reels, heat resistance due to proximity to the drag stack might need to be considered. Folks are probably going to prefer anodized aluminum, but then the cost starts climbing.
The design challenge is going to be the spring and nut that goes inside the knob. Since I have an unreasonable hatred of inserts, the way that I did this was to go through the top and use a screw on cap on the out facing side of the knob. The allowed me to have a more solid base. Sal wanted me to machine knobs for the bigger Pens like the 750. I never finished the project, but my plan was to figure out to use bellevilles instead of a coil spring so that the drag ramp up rate could be customized by unscrewing the cap and replacing bellevilles. Don't know if this would have worked out.
I am interested in seeing what Tom comes up with. All of his reel stuff has been top notch.
-J
Another part of the problem is many people have a tendency to tighten down the drag tighter than the reel's line rating compacity. That puts an awful lot of stress on the weak spots around the center hole and/or threaded inserts. It exacerbates the problem when they leave them tightened down when not in use.
Found these. There is a 5th but that ones cracked. Also got the newer ones.
Nice knobs. Which reels are they for? In need of 720/722 and have never seem power drag written on them
Tony, that's a great idea!!!!
Tommy makes a great point on Penn plastic knobs. I have reels with plastic drag knobs from other manufacturers that don't have issue of cracking and are even older. We can't go back in time only forward. Its a lesson on USA manufacturing thinking of planned obsolescence. Its like my 1987 German sports car vs. others.
I have a stress cracked 720/722 knob that has never been used. and the stress cracks on these knobs are all relieving directionally outward for the depth of the insert and not downward or diagonally, so I am pretty confidant this is from the internal stress from the brass insert over time.
IMHO, this was a design/manufacturing defect that took a couple decades to manifest, so I don't think we can be too harsh on Penn.
Having said that, I also agree that cranking down on vintage plastic drag knobs and especially storing them cranked down is probably not a good idea.
-J
Quote from: thorhammer on May 12, 2023, 02:18:38 PMTony, that's a great idea!!!!
I thought so too, but no one seems overly impressed haha.
tony
I think it's a great idea; I'd be interested in 716z, 714z, and 712Z. It's just a question of price...
Woodpuppy,
I have a new 714z spool I can send you, including the hard to find drag knob :D . Make any donation you deem fair value for the spool and drag knob to Alan's charity and then PM me your address.
tony
Quote from: Fishgolfman on May 11, 2023, 02:14:01 PMWhile fishing remotely in another country...when knob broke .. guide resorted to a wing nut!! Ugly looking reel but worked till I was back in USA
;D ;D Good mate of mine had a newish Trinidad of which the handle broke, he did precisely what you did, except that it was ordinary 6 mm straight bolt, but the whole thing was skew as well and looked terrible.
He then fished where the Shimano Rep would see it and embarrassed him to the point where he received a new one eventually :d
This was all good natured!
The only all metal spinning drag knobs I have are on an early '40's M.G. 300(one plastic knob on a '60's 300 is cracked) and a DAM Quick 250 Standard-circa 1952. The Fin-Nor LT 100 comes close, but the bottom pressure unit is prolly graphite composite.
All metal from Tom sounds like a great Idea.
I donated a nice Shimano Torium to that charity several years ago. Asked for a receipt for tax purposes and never got a reply. In fact, couldn't get a response as to whether they ever received it or not...?
NOT saying at all NOT to donate, maybe some unknown problems were occurring then, but not now.