How to Remove Knobs


Rich Frahm
 

I am missing 2 knobs on my Tektronix 2430A...you can see one of them in the upper right of this photo: https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing

I do 3D printing and want to see if I can make new ones so would like to remove one to inspect it. What's the proper way to remove these knobs?

Thanks!

Rich


Craig Cramb
 

Rich,
What's the proper way to remove these knobs?
Pulling these off sometimes is no big deal but there is a big risk of breaking one of the clips inside the knob. I take my wife’s hair drier and warm it up pretty good to soften the plastic then use two small flat blade screw drivers under the back and light twist at the same time. It should pop right off. While it is still warm.

Craig

On Apr 11, 2020, at 9:57 AM, Rich Frahm <criageek@gmail.com> wrote:

I am missing 2 knobs on my Tektronix 2430A...you can see one of them in the upper right of this photo: https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing

I do 3D printing and want to see if I can make new ones so would like to remove one to inspect it. What's the proper way to remove these knobs?

Thanks!g

Rich



satbeginner
 

Yes, that's the way to do it, and if there is a internal clip broken, use some rtv (silicone) when you put it back.
That way they can be removed again... :-)


n4buq
 

In case you'd rather have a factory original (as opposed to a 3D printed knob) I recently purchased a knob (similar to the one you're looking for but has the bar on it) from an eBay listing from a seller in Great Britain. I was pretty satisfied with what I got and I think they have the non-bar version as well.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Rich Frahm" <criageek@gmail.com>
To: TekScopes@groups.io
Sent: Saturday, April 11, 2020 9:57:47 AM
Subject: [TekScopes] How to Remove Knobs

I am missing 2 knobs on my Tektronix 2430A...you can see one of them in the
upper right of this photo:
https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing

I do 3D printing and want to see if I can make new ones so would like to
remove one to inspect it. What's the proper way to remove these knobs?

Thanks!

Rich




Chuck Harris <cfharris@...>
 

I have taken to using a pair of real needle nosed pliers
as an adjustable prying tool. But, then the only such knobs
I need to remove are the knobs under the CRT of a 2465 family
scope, and the scope's bezel makes a convenient purchase point.

The trick to not breaking the molded clips is to go slow and
uniformly pry under the skirt. If you let the knob cock to one
side, or the other it will break instantly.

Warming the knob makes it much more resilient to all sorts of
abuse.

-Chuck Harris

Craig Cramb wrote:


Rich,
What's the proper way to remove these knobs?
Pulling these off sometimes is no big deal but there is a big risk of breaking one of the clips inside the knob. I take my wife’s hair drier and warm it up pretty good to soften the plastic then use two small flat blade screw drivers under the back and light twist at the same time. It should pop right off. While it is still warm.

Craig
On Apr 11, 2020, at 9:57 AM, Rich Frahm <criageek@gmail.com> wrote:

I am missing 2 knobs on my Tektronix 2430A...you can see one of them in the upper right of this photo: https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing

I do 3D printing and want to see if I can make new ones so would like to remove one to inspect it. What's the proper way to remove these knobs?

Thanks!g

Rich





Brad Thompson
 

Chuck Harris wrote on 4/11/2020 1:12 PM:

I have taken to using a pair of real needle nosed pliers
as an adjustable prying tool. But, then the only such knobs
I need to remove are the knobs under the CRT of a 2465 family
scope, and the scope's bezel makes a convenient purchase point.

The trick to not breaking the molded clips is to go slow and
uniformly pry under the skirt. If you let the knob cock to one
side, or the other it will break instantly.

Warming the knob makes it much more resilient to all sorts of
abuse.
Hello--

I've had some success in removing friction-grip knobs by placing a
length of cable-lacing twine (*) under the knob on either side and
simultaneously  pulling the free ends of the twine to apply upward
pressure on both sides of the knob. (*) Any heavy-gauge string or
dental floss would likely also work, but lacing twine is waxed for better traction.)

On another knob-related subject, someone in the group inquired about
a source of tiny Allen wrenches. I can offer six NOS  0.050-inch (1/2 by 1 3/4 inch legs)
Allen hex wrenches for $5.00 postpaid to U.S. locations.

Questions honored, PayPal welcomed.

73--

Brad  AA1IP


Harvey White
 

Assuming that they're press fit ONLY, make two identical 2 tined ramps, where the distance between forks will accommodate the shaft and nut (if any).  Place one as far in as it will get.  That protects the panel.  Put the other one in from the other side and slowly compress them, that ought to wedge the knob off.

Another option would be to make a knob puller that looks a bit like the gear pullers you can buy.  You'd have to have a "platform" that would brace against the front panel and pull out.

I like the two wedges better.  (something similar is used for removing jacobs chucks from JT tapers in machining).

Harvey

On 4/11/2020 10:57 AM, Rich Frahm wrote:
I am missing 2 knobs on my Tektronix 2430A...you can see one of them in the upper right of this photo: https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing

I do 3D printing and want to see if I can make new ones so would like to remove one to inspect it. What's the proper way to remove these knobs?

Thanks!

Rich



Tony Fleming
 

Harvey, you are right, one can make a puller and or even get en inexpensive
faucet handle puller - they cost like $7 or so at any lumberyard - that is
the one I use.
Look here what you can get for $5.00 :
https://www.harryepstein.com/valve-faucet-handle-puller.html?gclid=CjwKCAjw1cX0BRBmEiwAy9tKHj_iIPn7xAMtTdDHXjyqs_iPuvRoTVieEqTW1AbDGsZ_z9xy595ysBoCZsUQAvD_BwE
One can improve it by putting a double sticking tape and attach thin
leather or something that makes it less slippery and soft so you don't
scratch the knob on the bottom. But that is sometimes too tight to fit, if
the knob is very close to the panel.
You all have a great EASTER!

On Sat, Apr 11, 2020 at 6:04 PM Harvey White <madyn@dragonworks.info> wrote:

Assuming that they're press fit ONLY, make two identical 2 tined ramps,
where the distance between forks will accommodate the shaft and nut (if
any). Place one as far in as it will get. That protects the panel.
Put the other one in from the other side and slowly compress them, that
ought to wedge the knob off.

Another option would be to make a knob puller that looks a bit like the
gear pullers you can buy. You'd have to have a "platform" that would
brace against the front panel and pull out.

I like the two wedges better. (something similar is used for removing
jacobs chucks from JT tapers in machining).

Harvey


On 4/11/2020 10:57 AM, Rich Frahm wrote:
I am missing 2 knobs on my Tektronix 2430A...you can see one of them in
the upper right of this photo:
https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing

I do 3D printing and want to see if I can make new ones so would like to
remove one to inspect it. What's the proper way to remove these knobs?

Thanks!

Rich






Rich Frahm
 

Thanks for all the ideas guys! I did break the first one I tried to remove but the second one came off ok with some heat. Here is the first prototype: https://drive.google.com/file/d/1rW9zR2inVmAxY-iVq69uUiHVP6kOtX6l/view?usp=sharing I don't know why the top half is so rough...I've printed knobs before that came out great. Although not this small. I was going to try to put in the "spring" pieces, but the fit is so snug that I don't think I have to. If I use them a while and they loosen up then I'll see if I can change them to put the spring pieces in, but I really don't think it'll be necessary.

Rich