Cracked Drag Knobs

[sandbar]

Happy Saturday everyone.
Watching football and messing with reels. I just ran into another Penn ultralight with a cracked drag knob and was wondering if anyone out there has successfully repaired one. I've seen many reels on EBay that I have not bid on because of this issue. The white drag knobs that are cracked are very obvious. The black ones are harder to detect in the photos. Replacement knobs seem to be as rare as hens teeth.
I was thinking about trying to glue a thin piece of plastic to the bottom of the knob to prevent further cracking and carefully trying to fill the cracks from the top side.
Is there a reliable plastic to plastic adhesive on the market that anyone could recommend?

[jurelometer]

It depends on the type of plastic.   If it is ABS (most likely), it can be chemically welded with acetone.  If you want to bridge some gaps, using the ABS glue that they use for abs pipes can work.  A trick that I have used for  filling voids  and gluing printed ABS parts is to dissolve some shaved sacrificial ABS scrap in acetone to make a slurry.   If acetone melts the part , it is pretty likely to be ABS.

These parts usually crack from internal stresses from uneven cooling when originally molded, or from the pressure from the metal parts press fit in.  Over time, they eventually fracture, especially with a bit of use, so structurally they are no longer very strong, even if repaired.  Buying NOS parts is the best way to go, but don't expect these to last as long as the original once put into service, because they will also have the same long-term internal stresses.

Don't know if gluing a shim will help, but if you want to try it, make sure that it is the same type of plastic as the part.  The shim also has to not contact the spool, so that it does not rub when the spool is spinning from drag.


-J

[foakes]

Yes, this can be done, Steve —-

Type of glue I use is Tac-Glue for the under shim.  Glue, then clamp.  Let it cure overnight, even though it really only takes 20 minutes.  Longer is better.

After this disc is adhered, fill the crack in the drag knob with JB Weld Plastic.

If you try to bring the cracked area together as original —- it will just put additional stress on another part of the knob —- then crack in a new spot.

I sent you a new Penn 716Z black knob yesterday —- along with that DQ 1001 I built for you.  It is in a plastic sleeve stapled to the service tag.

Best, Fred

[sandbar]

Fred
Do you use a Teflon drag washer for the shim or some other type of plastic?

[foakes]

Just Teflon, Steve —-

I have only done this a few times when no other new knobs were available —- and even at that it is not as strong as a factory new knob.  Just a fix that works in a pinch.

The Penn knobs on the UL's are notorious for these cracks.

The larger drag knobs for the larger Penns seem to not crack —- likely since they are thicker.

DQ's & Mitchell's seldom crack.

It would be interesting to see if I could modify DQ drag knobs for these Penns.

It would depend on the size of the threads, changing Metric to Standard, the depth, and circumferences.  But I have a couple of thousand DQ drag knobs that I seldom need to replace since they seldom break.

There would be a lot of Penns out there with maroon knobs!

Best, Fred

[sandbar]

Wouldn't that be a great thing if the Penns, that may have been copies of the D.A.M. reels, get rescued by higher quality D.A.M. parts?

[Woodpuppy]

I find myself in the same spot as the OP- an eBay 716Z that is in very nice condition, but the knob broke apart after loading the reel with 6-lb mono tonight. So bummed! A short term functional fix could be a second flat metal drag washer and the central nut left from the broken drag nut, but that's not ideal. If I had any skill with a benchtop lathe I could turn a knob from black delrin and epoxy the nut into it.

I'm keeping an eye out on eBay for a spare...
@foakes is there any chance you've got a spare NOS 716Z knob? I dig the older flat design like the 716/no Z.

[foakes]

@foakes is there any chance you've got a spare NOS 716Z knob? I dig the older flat design like the 716/no Z.

Have one new one that is loose, and another on a complete spool.

And some on complete reels.

I will check tomorrow if there are any others.

Best, Fred

[Woodpuppy]

@foakes is there any chance you've got a spare NOS 716Z knob? I dig the older flat design like the 716/no Z.

Have one new one that is loose, and another on a complete spool.

And some on complete reels.

I will check tomorrow if there are any others.

Best, Fred

I'm unsure of buying / selling protocols; I am interested in both the complete spool and the loose knob if they are available.

[foakes]

Glad to check tomorrow —- then will PM (private mail) you through the site.

Best, Fred

[Woodpuppy]

Thank you kindly.