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Gauging interest in a run of reproduction knob tips


thespin@...
 

Hey all,

I've noticed that a lot of the lever knob tips have cracked due to the combination of being made of bakelite and the internal stresses of the leaf spring. I'd like to do a short run of replacement knobs. I've tried several different 3D printing processes and haven't been totally happy with any of them. In particular, FDM tends to have pronounced layer lines, and small enough nozzles require extremely high melt flow rates restricting the choice of materials and thus colors. I also have an SLA printer, but these resins result in parts that last a few months before cracking due to UV exposure. Thus, urethane casting and injection molding are seemingly the best options. MJF or SLS may be ok but I'm not a huge fan of the texture.

If you'd be interested, I'd appreciate a response to the following survey.

https://forms.gle/U4LUT8LiVHhDk911A

Best wishes,
Evan


 

What machines would these "knob tips" be for? E.g. are we talking about the tips for the input coupling (AC/GND/DC) lever on a 400-series scope?

-- Jeff Dutky


thespin@...
 

I would do a reproduction mold for part 366-0215-00 and run different colors to suit. I think 366-0215-00 is used on 400 series... it's certainly also used on the 556, 547, etc.


Dave Wise
 

The Tek lever knob tips are P/N 366-0215-xx. They're widely used, e.g. Type 453 and 547 scopes and 1A1, 1A2, 1A4, and 1A5 plugins.

For what it's worth, I replace broken ones with the cylindrical tact-switch cap made by E-Switch, part number 1RDGR, $0.18 each at Mouser.
Description is "Switch Bezels / Switch Caps RND DARK GRAY CAP". It doesn't have the feel of the original but it works and it stays in place.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of thespin via groups.io <thespin=gmail.com@groups.io>
Sent: Wednesday, December 02, 2020 9:27 AM
To: TekScopes@groups.io
Subject: [TekScopes] Gauging interest in a run of reproduction knob tips

Hey all,

I've noticed that a lot of the lever knob tips have cracked due to the combination of being made of bakelite and the internal stresses of the leaf spring. I'd like to do a short run of replacement knobs. I've tried several different 3D printing processes and haven't been totally happy with any of them. In particular, FDM tends to have pronounced layer lines, and small enough nozzles require extremely high melt flow rates restricting the choice of materials and thus colors. I also have an SLA printer, but these resins result in parts that last a few months before cracking due to UV exposure. Thus, urethane casting and injection molding are seemingly the best options. MJF or SLS may be ok but I'm not a huge fan of the texture.

If you'd be interested, I'd appreciate a response to the following survey.

https://forms.gle/U4LUT8LiVHhDk911A

Best wishes,
Evan


greenboxmaven
 

If you are speaking of the small teardrop shaped knobs for the lever switches, I think there is considerable need for them. I could use about fifteen of them right now, and more later. Most of the ones I need are to replace missing ones, but the metal spring inside several has started a crack in the knob which will only spread.

Bruce Gentry, KA2IVY

On 12/2/20 13:36, Dave Wise wrote:
The Tek lever knob tips are P/N 366-0215-xx. They're widely used, e.g. Type 453 and 547 scopes and 1A1, 1A2, 1A4, and 1A5 plugins.

For what it's worth, I replace broken ones with the cylindrical tact-switch cap made by E-Switch, part number 1RDGR, $0.18 each at Mouser.
Description is "Switch Bezels / Switch Caps RND DARK GRAY CAP". It doesn't have the feel of the original but it works and it stays in place.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of thespin via groups.io <thespin=gmail.com@groups.io>
Sent: Wednesday, December 02, 2020 9:27 AM
To: TekScopes@groups.io
Subject: [TekScopes] Gauging interest in a run of reproduction knob tips

Hey all,

I've noticed that a lot of the lever knob tips have cracked due to the combination of being made of bakelite and the internal stresses of the leaf spring. I'd like to do a short run of replacement knobs. I've tried several different 3D printing processes and haven't been totally happy with any of them. In particular, FDM tends to have pronounced layer lines, and small enough nozzles require extremely high melt flow rates restricting the choice of materials and thus colors. I also have an SLA printer, but these resins result in parts that last a few months before cracking due to UV exposure. Thus, urethane casting and injection molding are seemingly the best options. MJF or SLS may be ok but I'm not a huge fan of the texture.

If you'd be interested, I'd appreciate a response to the following survey.

https://forms.gle/U4LUT8LiVHhDk911A

Best wishes,
Evan












Dave Wise
 

Don't get me wrong, I'd love to get good reproductions. The tact-switch caps are better than bare levers, but I only put them on because cracked falling-off bats MAKE ME CRAZY.

Dave Wise
________________________________________
From: David Wise
Sent: Wednesday, December 02, 2020 10:36 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Gauging interest in a run of reproduction knob tips

The Tek lever knob tips are P/N 366-0215-xx. They're widely used, e.g. Type 453 and 547 scopes and 1A1, 1A2, 1A4, and 1A5 plugins.

For what it's worth, I replace broken ones with the cylindrical tact-switch cap made by E-Switch, part number 1RDGR, $0.18 each at Mouser.
Description is "Switch Bezels / Switch Caps RND DARK GRAY CAP". It doesn't have the feel of the original but it works and it stays in place.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of thespin via groups.io <thespin=gmail.com@groups.io>
Sent: Wednesday, December 02, 2020 9:27 AM
To: TekScopes@groups.io
Subject: [TekScopes] Gauging interest in a run of reproduction knob tips

Hey all,

I've noticed that a lot of the lever knob tips have cracked due to the combination of being made of bakelite and the internal stresses of the leaf spring. I'd like to do a short run of replacement knobs. I've tried several different 3D printing processes and haven't been totally happy with any of them. In particular, FDM tends to have pronounced layer lines, and small enough nozzles require extremely high melt flow rates restricting the choice of materials and thus colors. I also have an SLA printer, but these resins result in parts that last a few months before cracking due to UV exposure. Thus, urethane casting and injection molding are seemingly the best options. MJF or SLS may be ok but I'm not a huge fan of the texture.

If you'd be interested, I'd appreciate a response to the following survey.

https://forms.gle/U4LUT8LiVHhDk911A

Best wishes,
Evan


Terry Gray
 

Don't think the original knob is made from bakelite. Bakelite is a "thermosetting" material and it would not be likely that it would ever crack like plastic.  It is definitely a type of plastic (melts with heat applied). Anyway, I am very happy that Evan is considering reproducing them. Should be a lot of interest in this.
    How about also reproducing the LeCroy 9300 series (you might also consider the LeCroy LA314 and similar scopes in that LA300 series--originally designed by Iwatsu) front panel knobs >>I definitely know that these would be VERY popular. The plastic shaft on the encoders break off with the knobs and both pieces end up lost. In my experience you can often repair the encoder and I think that the encoders themselves are still available (part numbers are available in the LeCroy blog history) but the knobs seem to be unobtainable. Have never seen a source for the knobs and have looked for years. You can sometimes find a knob that will work or can be modified to work but they don't match the others.  And these older LeCroy oscilloscopes are fantastic (digital scopes over 1GHz, analog up to 470MHz) and unbelievably cheap compared to original cost (for instance the LA314H originally listed for $14,000 in the 90's)>>> I picked my first LA314H up on Ebay for $99.00 BUT it had CONSIDERABLE problems in the out-sourced power supply). Reply to me if you are interested in any or all of the problems experienced. But most of the problems can be rectified easily IF you catch them early enough. It really gets bad if you wait until disaster occurs (like my first one). These SMPS are great until they fail catastrophically.      Terry

On Wednesday, December 2, 2020, 11:27:46 AM CST, thespin@gmail.com <thespin@gmail.com> wrote:


Hey all,

I've noticed that a lot of the lever knob tips have cracked due to the combination of being made of bakelite and the internal st

resses of the leaf spring. I'd like to do a short run of replacement knobs. I've tried several different 3D printing processes and haven't been totally happy with any of them. In particular, FDM tends to have pronounced layer lines, and small enough nozzles require extremely high melt flow rates restricting the choice of materials and thus colors. I also have an SLA printer, but these resins result in parts that last a few months before cracking due to UV exposure. Thus, urethane casting and injection molding are seemingly the best options. MJF or SLS may be ok but I'm not a huge fan of the texture.

If you'd be interested, I'd appreciate a response to the following survey.

https://forms.gle/U4LUT8LiVHhDk911A

Best wishes,
Evan


thespin@...
 

I'm only considering one single part at the moment. Injection molds are extremely expensive, and I'm a mere postdoc. I only have one lecroy scope and it's relatively modern, and this project is mostly motivated by my love for my 556 and 547. I have a few options for how to make the parts -- have a mold made, or make it myself and make the parts on a friend's press. The former is expensive, and the second is labor intensive. I want to make sure I break even on the money invested or am appropriately compensated for the labor.


 

I could use 10 of them if you can keep the cost around $2 to $3 each.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of thespin@gmail.com
Sent: Wednesday, December 02, 2020 1:12 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Gauging interest in a run of reproduction knob tips

I'm only considering one single part at the moment. Injection molds are extremely expensive, and I'm a mere postdoc. I only have one lecroy scope and it's relatively modern, and this project is mostly motivated by my love for my 556 and 547. I have a few options for how to make the parts -- have a mold made, or make it myself and make the parts on a friend's press. The former is expensive, and the second is labor intensive. I want to make sure I break even on the money invested or am appropriately compensated for the labor.







--
Dennis Tillman W7pF
TekScopes Moderator