10 replies to this topic

[magnusl]

Hi!

 

I'm looking for a reducer, to place a small scope on a VIxen dovetail in a Losmandy clamp. What I'm looking for is this functionality: 

 

 

 

But I'd like to 3D print it myself (PETG + carbon). Anyone knows of a similar device or have ideas on how to achieve this functionality?

 

Magnus

[nic35]

You probably want to post this question here - https://www.cloudyni...nted-astronomy/

 

If you can't find an stl file to print this specific device, you could probably find separate Losmandy and vixen stl files and merge them together.  Maybe in Tinkercad ?  Certainly in Freecad - but that's got a steepish learning curve.

 

This should be printed standing on end, otherwise you are likely to hear some concerns about layer separation.   

 

j

[whereIsIt]

There are some 3D-Printable's here and if you search around on other 3D-print sites, may find exactly what you want...

[magnusl]

Hi!

 

Ops, did not realize there was a dedicated 3D-printing thread...

 

Yeah, I know I can play with existing models ... was just thinking if someone else already had... interestingly enough, I can not find one that does what I want on Thangs, Thingiverse, Printables, or Yeggi.. I guess I can contribute one soon then. 

 

Magnus

[whereIsIt]

Hi!

 

Ops, did not realize there was a dedicated 3D-printing thread...

 

Yeah, I know I can play with existing models ... was just thinking if someone else already had... interestingly enough, I can not find one that does what I want on Thangs, Thingiverse, Printables, or Yeggi.. I guess I can contribute one soon then. 

 

Magnus

Sounds like you can doodle up something but, if interested, I did this in about 2-Minutes in FreeCAD.

 

I have No dimension's for any of it - just graphically represented something similar. If you want to Provide Real Dimension's ( all of them), I would complete the Model...

Attached Thumbnails

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[magnusl]

Wow, that was cool! You are far better at that than I am. 

 

Real dimensions: the ones that matter are these, I guess: 

 

Losmandy dovetail - I am measuring an existing dovtail (not clamp):

73 mm at the widest

64 at the narrowest

it is 10 mm high. The angle should be 60 degrees (https://www.cloudyni...pecs/?p=5216270)

 

Vixen dovetail: 

43 mm at teh widest

37 at eh narrowest

14 mm high

 

Magnus

[whereIsIt]

Wow, that was cool! You are far better at that than I am. 

 

Real dimensions: the ones that matter are these, I guess: 

 

Losmandy dovetail - I am measuring an existing dovtail (not clamp):

73 mm at the widest

64 at the narrowest

it is 10 mm high. The angle should be 60 degrees (https://www.cloudyni...pecs/?p=5216270)

 

Vixen dovetail: 

43 mm at teh widest

37 at eh narrowest

14 mm high

 

Magnus

 

Happy to help.

 

Though it would take me only a few minutes to do this kind of stuff, it would take me far too long to figure out the full dimension's needed to model it such that you'd be happy with it.

Yes, I can 'assume' some but, experience informs me that some would need to be tweaked... You say "...the one's that matter, I guess"... therein lies the Rub...

 

I need 'All of the geometry' dimensioned. I don't like guessing and re-working...

 

Attached PDF is for you to  mark-up... pencil is fine. And attach to the post or post Screenshot/photo.

Leave Nothing un-dimensioned.  If it's a dimension you don't care about, I still want one or, you get the dim's that I conjure up and I don't want to be re-working it...

 

Also, as I look at the image you posted, it looks like the Edge on right-side is Vertical (not 60º) and top edge is chamfered...?

 

And, the Threads for your Knobs?  I can put Printable threads in the hole but I need the Thread size (M4...M6...etc or other. Or, just holes for you to Thread with a Tap...?

 

So, Please, put a dimension on Every line...as if you were modeling it.

Thanks

 

Oh, and 'Quote' my post/other or I don't get notified of your Post/Response...

 

UPDATE:

Over morning Coffee, I modeled the shape using your Dimension's.

 

I did it to show, by example, why I want 'you' to provide all dimensions, hoping you'd discover the 'mathematical incongruity' of the Dim's you posted.  Perhaps you've discovered them by now...

 

The image posted below shows that the 64 and 37 (the Narrowest) are Not possible if the other Dim's are as you posted... Not to mention your posted Photo with it's geometry unrelated to the Link you posted.

 

That said, the STL file for printing is attached. Unlikely it will be useful beyond a paper-weight...

 

 Hum.stl   2.23KB   2 downloads  tofu.pdf   108.46KB   3 downloads

 

ADDITIONAL UPDATE: Only to amuse myself...and to show what could be done quickly (in FreeCAD). I inverted (the Part) and added two M4-Thumbscrews.

Image attached... The STL is too large for posting here (the Thumbscrew-Threads cause this) 

I deleted the Thumbscrews and now post a smaller STL

 

I'll leave this Topic alone, now...

 

 hum-Body003.stl   3.01KB   0 downloads

Edited by whereIsIt, 19 February 2025 - 02:37 PM.

[magnusl]

Hi!

 

I've been occupied by work and stuff, but made some measurements today and produced the attached. I am not sure I follow you with the mathematical errors - I simply measured the clamps and dovetails I have. And 60 degrees is for the Losmandy side, not the Vixen side. 

 

Maybe this helps?

 

Magnus

 

 

Attached Files

•  SCN20250220095533277.pdf   415.4KB   4 downloads

Edited by magnusl, 20 February 2025 - 04:03 AM.

[whereIsIt]

Hi!

 

I've been occupied by work and stuff, but made some measurements today and produced the attached. I am not sure I follow you with the mathematical errors - I simply measured the clamps and dovetails I have. And 60 degrees is for the Losmandy side, not the Vixen side. 

 

Maybe this helps?

 

Magnus

Note: To avoid a plethora of email/notification's, my settings are set to notify me Only if my Post is Quoted or Liked.

 

By curiosity only, I came back to this post and see your response.

Thank you for the dimensions/etc. Be sure to quote me/like if wanting me to be notified...

 

Re: The Angle's/Dim's
Best explained Graphically, imagine a Fireman is on a Ladder leaning 60º and climbs to the Height of a 10th floor Window.
He reaches out the length of his Arm but can't touch the Window.
He either wants Longer Arms or, the Ladder at a Different Angle or, the Window to be Raised so it get's closer to the Ladder as he climbs Higher.

Thus, you can't specify all the dimensions as one of them is a Result of the other's.

 

The Vixen's 36.5 and 43.5 are fine and at a Height of 10mm, the resulting Angle of 70.71º is Locked-in

 

The Losmandy Angle of 60º is fine but, at a specified Height of 10, you can have Only one of the Specified Lengths (either 74 or 63). You'll need to live with 62.453 instead of 63.

 

Attached are: Zipped PDF and STL and STEP.  You did Not specify the Hole size or if wanting them Threaded (hence, my point of wanting Everything specified so we avoid back-and-forth dimension tweaking...)

 

Re the Threads, I set the Hole to M3 and you can Self-Tap them with an M3 Screw or M3-TAP (the plastic will shrink enough to provide some meat (so to speak).

If you know how to do Modifications with CAD using the STEP, great. Some Print software features 'Modification' tools that you can use to accomplish Hole tweaking and/or Solid-Material for Threading and/or Plugging it up... Thus, you can Plug it, Print that Zone at 100% Infill, then Drill&Tap it.

Look for some recent posts of mine showing how to use ORCA's modification tool to do it...

 

Screenshots of Model and Dim's.  I Assumed all other Geometry as I saw fit...

Attached Thumbnails

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Attached Files

•  LOS_VEX.zip   129.65KB   3 downloads

Edited by whereIsIt, 20 February 2025 - 02:23 PM.

[mich_al]

I once 3D printed a device that included a finder foot.  I carefully measured an existing foot and used those dimensions in the 3D print.  It came out too small.  I was using the most common materials for the print who's name escapes me just now.  My cheezy solution was to tell the slicer to increase all dims by some small percent & that was fine for my non-critical device.  Just be aware.

[whereIsIt]

I once 3D printed a device that included a finder foot.  I carefully measured an existing foot and used those dimensions in the 3D print.  It came out too small.  I was using the most common materials for the print who's name escapes me just now.  My cheezy solution was to tell the slicer to increase all dims by some small percent & that was fine for my non-critical device.  Just be aware.

Of course. Whether 3D-Print or Injection molded, 99% of Plastic Shrinks. Usually less than 1% but, it depends on the Shape and Size and Features...

Most un-carbon-filled PLA shrinks about 1/2 % and User's can accommodate for that using the Scale feature in Print-Software.

 

For most 3D-Printed things (statues and the usual junk, it doesn't matter. For Engineering-Related stuff, it's more important...

 

When we made Molds for Injection molding, we burned/machined the cavities larger to account for it...

Edited by whereIsIt, 20 February 2025 - 03:53 PM.