Plastic Part for a 3L5


Jim Adney
 

There is a small, white plastic part in a 3L5 that translates the axial motion of the "Pull for Divide by 100" knob to a slide switch. I had a 3L5, sold long ago, that was missing that part, presumably because it had broken and fallen out of the plugin. I have long wondered how hard it would be to make replacements, and 3D printers probably make that easy now. The part is 376-0063-00 "COUPLER, slide switch to disk". I asked Deane Kidd about these long ago and he didn't have any, but he managed to send me a copy of the Tek drawing. The copy is extremely poor, however, so I can barely make out what it's supposed to look like. Fortunately, I can see what originals looked like in my other 3L5s.

My question is whether this part was used in other plugins and if there would be any point in my getting a few 3D printed. It looks like a fairly fragile piece, so it wouldn't surprise me if they were a commonly needed part, but only if they were used in several more common plugins. Let me know if you know of other applications.

thanks,


Dave Casey
 

Pretty sure I've seen aluminum versions in various 7k plugins. The 7B53A
comes to mind.

Dave Casey

On Tue, May 4, 2021 at 5:33 PM Jim Adney <jadney@vwtype3.org> wrote:

There is a small, white plastic part in a 3L5 that translates the axial
motion of the "Pull for Divide by 100" knob to a slide switch. I had a 3L5,
sold long ago, that was missing that part, presumably because it had broken
and fallen out of the plugin. I have long wondered how hard it would be to
make replacements, and 3D printers probably make that easy now. The part is
376-0063-00 "COUPLER, slide switch to disk". I asked Deane Kidd about these
long ago and he didn't have any, but he managed to send me a copy of the
Tek drawing. The copy is extremely poor, however, so I can barely make out
what it's supposed to look like. Fortunately, I can see what originals
looked like in my other 3L5s.

My question is whether this part was used in other plugins and if there
would be any point in my getting a few 3D printed. It looks like a fairly
fragile piece, so it wouldn't surprise me if they were a commonly needed
part, but only if they were used in several more common plugins. Let me
know if you know of other applications.

thanks,






Michael W. Lynch
 

Post a picture, If it is like the ones that Dave is describing from the 7B53, it would be a simple task to turn out the part from nylon on a lathe. if supplied the dimensions and pictures, I could probably make one from nyl0n stock or model one and 3D print it. I looked in the TEK "Mechanical parts" catalog, but did not see this part listed along with the other shaft couplings.

--
Michael Lynch
Dardanelle, AR


Jim Adney
 

On Wed, May 5, 2021 at 09:56 AM, Michael W. Lynch wrote:

Post a picture, If it is like the ones that Dave is describing from the 7B53,
it would be a simple task to turn out the part from nylon on a lathe.
Well, right now it's buried in my 3L5, but maybe I can get a somewhat useful macro shot of it. I'm more likely to be able to make a sketch from the almost unreadable drawing and take a photo of that. It's NOT a lathe part; all right angles and square inside and outside corners.

I believe a replacement could be much beefier than the original. The OE Tek part strikes me as skimpy and weak. I like the idea of making one from Aluminum, but there's plenty of room to make plastic replacements with much thicker walls.


Michael W. Lynch
 

On Wed, May 5, 2021 at 12:54 PM, Jim Adney wrote:


Well, right now it's buried in my 3L5, but maybe I can get a somewhat useful
macro shot of it. I'm more likely to be able to make a sketch from the almost
unreadable drawing and take a photo of that. It's NOT a lathe part; all right
angles and square inside and outside corners.

I believe a replacement could be much beefier than the original. The OE Tek
part strikes me as skimpy and weak. I like the idea of making one from
Aluminum, but there's plenty of room to make plastic replacements with much
thicker walls.
Jim,

I certainly understand being buried in a project. I have time and 3D printers, willing to help if needed.

I was thinking of that shaft collar that was round and had a single groove in the center to move a slide switch. From your description, it sounds like a more complex part.

When 3D printing this type of part, it is almost essential to have old parts on an example to direct measure and to see the finer details of the part. If you have room, the part can certainly be made heavier.

Let me know if I can be of assistance. .

--
Michael Lynch
Dardanelle, AR


Jim Adney
 

On Tue, May 4, 2021 at 05:39 PM, Dave Casey wrote:

Pretty sure I've seen aluminum versions in various 7k plugins. The 7B53A comes to mind.
Okay, I'm looking at the exploded view, Figure 1, of the 7B53A in

https://w140.com/smb/7b53a_an_svc_sm.pdf

I see a part on the Time Base shaft, #145, that looks like it could be used to trigger a slide switch, #124, in the same way, but I don't see which part interfaces those two. Can you pick it out?


Jim Adney
 

On Wed, May 5, 2021 at 01:21 PM, Michael W. Lynch wrote:

I have time and 3D printers, willing to help if needed.
Thanks for the offer, but I have a local friend with a 3D printer. I totally agree with the need to be able to test any replacements in place, making the local option the best one.


Michael W. Lynch
 

On Wed, May 5, 2021 at 01:23 PM, Jim Adney wrote:



Pretty sure I've seen aluminum versions in various 7k plugins. The 7B53A
comes to mind.
Okay, I'm looking at the exploded view, Figure 1, of the 7B53A in

https://w140.com/smb/7b53a_an_svc_sm.pdf

I see a part on the Time Base shaft, #145, that looks like it could be used to
trigger a slide switch, #124, in the same way, but I don't see which part
interfaces those two. Can you pick it out?
Jim,

I think the part that Dave is speaking of is #87 "Spool,switch actuator" Shown on page # 2 of the exploded diagram. #87 is secured to the shaft and moves the "switch detent" #91 as the knob is pulled out.

This was a simple collar with a groove in the center that I was suggesting to be built on a lathe. .

--
Michael Lynch
Dardanelle, AR


David Holland
 

Is this the part you're talking about?

https://groups.io/g/TekScopes/photo/263828/3220488?p=Created,,,20,2,0,0

(Old picture, from mine). Obviously, mine is in working order, but I can
see the difficulty in replicating it. I'm not so sure about the strength
of 3D printed PETG and/or PLA. Maybe a job for a CNC router and a
better plastic?

David

On Wed, May 5, 2021 at 2:31 PM Jim Adney <jadney@vwtype3.org> wrote:

On Wed, May 5, 2021 at 01:21 PM, Michael W. Lynch wrote:

I have time and 3D printers, willing to help if needed.
Thanks for the offer, but I have a local friend with a 3D printer. I
totally agree with the need to be able to test any replacements in place,
making the local option the best one.






Michael W. Lynch
 

David,

I'll bet that is it. That certainly is a complex little piece of molding.

--
Michael Lynch
Dardanelle, AR


Jim Adney
 

On Tue, May 4, 2021 at 05:32 PM, Jim Adney wrote:

My question is whether this part was used in other plugins
Okay, I thought to check the obvious 1L5, and I see that it uses the same part: 376-0063-00, #73 in Figure 2.


Michael W. Lynch
 

Well., I was totally off on which part you were referring to. I had in mind a shaft collar or coupler.

--
Michael Lynch
Dardanelle, AR


Jim Adney
 

On Wed, May 5, 2021 at 01:47 PM, David Holland wrote:

Is this the part you're talking about?

https://groups.io/g/TekScopes/photo/263828/3220488
Yes, it's there, way in the background. It's hidden behind the shaft and the bits on the shaft. The Al disk engages the part I'm asking about.

Here are two photos I just took of it from two different angles. Sorry, they are poor and we don't get to see much in either photo.

groups.io/g/TekScopes/photo/262268/3220553

groups.io/g/TekScopes/photo/262268/3220555

If you'll scan to the photos to the left and right of these two, you'll find a photo of the Tek drawing for this part, as well as a sketch I made, trying to make some of the dimensions clearer. There are some things in the Tek drawing that I'm not clear on, mostly the ribs in the center hole which may be to eliminate clearance to the slide switch toggle. It's possible that those ribs are the only thing that holds that part in place, which seems pretty odd.


Jim Adney
 

On Wed, May 5, 2021 at 01:47 PM, Michael W. Lynch wrote:

I think the part that Dave is speaking of is #87 "Spool,switch actuator" Shown
on page # 2 of the exploded diagram. #87 is secured to the shaft and moves the
"switch detent" #91 as the knob is pulled out.
Okay, I see them now. Those are different. #87 may be a simple collar, possibly Al, and certainly easy to reproduce.

#91 might well serve the same purpose as the part I'm asking about, but it appears to be quite different, and it's part number is completely different.

This was a simple collar with a groove in the center that I was suggesting to be built on a lathe.
Yes, that would have been nice and easy.

thanks,