3d Printed Carriage for Thorlabs XT66 optical rail

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kaleun96
Posts: 270
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

3d Printed Carriage for Thorlabs XT66 optical rail

Post by kaleun96 »

Hello, back again with some more 3D printed creations that I thought some here might be interested in.

As a quick background: my stacking setup is based on two XT66 rails in a vertical configuration and I've previously been using a 150mm optical breadboard mounted to an upside-down Arca clamp to attach and slide along the horizontal portion of the rail. This works fine but is annoying to adjust (loosen, move, then tighten), it's quite imprecise, and very difficult to move accurately if the weight on the plate is not well-balanced.

So my solution was to use some rollers from a V-slot extrusion kit and 3D print a female adapter to fit the XT66 dovetail. This worked well and slid quite smoothly but it did have a bit of "stick" so needed a bit more force to first get it moving. Next idea was to add a M8 threaded rod and a bearing to create a linear rail that would drive the carriage. This addition worked better than expected and was quite cheap to make given it just uses standard hardware components.

Next iteration I'll integrate the block with the nut for the M8 rod with the carriage itself, at the moment it is secured to the 150mm optical breadboard attached to the carriage. I might also think about moving to a proper Acme screw and hardware, though it's worth keeping the cheaper version with standard hardware as an option too I think.

I also have some minor tweaks to the tolerances to find that perfect balance between minimising roll and pitch movement while not increasing the friction too much, will be happy to share the STL or Fusion 360 files after that. For those who are 3D printer-less, I've used 3D Hubs before and found it quite easy to use and relatively cheap. Let me know if you have any ideas or feedback that I could incorporate into a next iteration!
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There's a small gap between the flat/horizontal male and female parts of the dovetail as I wanted to minimise friction and instead have contact primarily at the angled edges and the ridge running down the middle.
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- Cam

lothman
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Joined: Sat Feb 14, 2009 7:00 am
Location: Stuttgart/Germany

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by lothman »

Hi Kaleun96,

=D> so you did it :D another thorlabs rail setup. You could also make grip your rollers into the V-groove oh the rail instead of the slider.

I use an xy-table like this on Aliexpress, bolted to an Arca clamp. Rough positioning by the Arca clamp and fine tuning by the knobs. I can even put one of the small led panels between the xy-table and the rail what allows transmitted light or background illumination.

Image

kaleun96
Posts: 270
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by kaleun96 »

lothman wrote:
Sun Oct 10, 2021 11:07 am
Hi Kaleun96,

=D> so you did it :D another thorlabs rail setup. You could also make grip your rollers into the V-groove oh the rail instead of the slider.

I use an xy-table like this on Aliexpress, bolted to an Arca clamp. Rough positioning by the Arca clamp and fine tuning by the knobs. I can even put one of the small led panels between the xy-table and the rail what allows transmitted light or background illumination.
Hey Lothar! Yeah I've had this setup since about January or February now, the simplicity of your design won me over :D

Unfortunately the rollers don't quite fit into the dovetail groove on two counts: first, the nut holding the rollers at the bottom is too wide and hits the XT66 rail and, second, the rollers are also slightly too thick so that bottom edge of the roller barely sits into the groove - there's quite minimal engagement - and the bottom of the roller contacts the XT66 rail so it's not quite ideal. An alternative would perhaps to be to drop the rollers down and have them ride in the middle grooves of the XT66 rail but I don't think this groove is substantial enough to engage with the rollers to prevent them drifting or jumping out of the groove. Perhaps there are some other rollers that could be bought to fit the dovetail though.

The XY table looks good! For me it might have more limited use cases as I do like having the breadboard pattern for mounting specimen holders or the like but I'm sure there's something out there that would work for what I need. But I do like making things with the 3D printer where possible because I can customise it exactly as I need, e.g. the off-centre hole spacing so that the 150mm optical breadboard sits centre on the carriage. For work above 10x I think you'd need to either buy something purpose-built such as what you use or kit this out with a proper acme screw with backlash nuts and much tighter tolerances. For photographing coins and insects I think it'll do though :)
- Cam

lothman
Posts: 956
Joined: Sat Feb 14, 2009 7:00 am
Location: Stuttgart/Germany

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by lothman »

kaleun96 wrote:
Sun Oct 10, 2021 11:52 am


Unfortunately the rollers don't quite fit into the dovetail groove on two counts: first, the nut holding the rollers at the bottom is too wide and hits the XT66 rail and, second, the rollers are also slightly too thick so that bottom edge of the roller barely sits into the groove - there's quite minimal engagement - and the bottom of the roller contacts the XT66 rail so it's not quite ideal.
But why don`t you design and print the roller to your need. Countersink the nut, increase the roller diameter and profile the roller so that the grip on the rail.

And for the xy-table you can flip out the glas plate and insert whatever you have printed :wink:

kaleun96
Posts: 270
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by kaleun96 »

lothman wrote:
Sun Oct 10, 2021 12:55 pm
kaleun96 wrote:
Sun Oct 10, 2021 11:52 am


Unfortunately the rollers don't quite fit into the dovetail groove on two counts: first, the nut holding the rollers at the bottom is too wide and hits the XT66 rail and, second, the rollers are also slightly too thick so that bottom edge of the roller barely sits into the groove - there's quite minimal engagement - and the bottom of the roller contacts the XT66 rail so it's not quite ideal.
But why don`t you design and print the roller to your need. Countersink the nut, increase the roller diameter and profile the roller so that the grip on the rail.

And for the xy-table you can flip out the glas plate and insert whatever you have printed :wink:
Ah I see what you mean, yeah you probably could print custom rollers but countersinking the nut would be tough given the bearing inside the roller. Though if you just had one "edge" for the roller instead of the usual two, that might give you enough height savings to get the nut to fit but I'd be worried the rollers wouldn't do nearly as good of a job at reducing roll and pitch given the one point of contact on each roller, plus either the added friction from the bottom of the roller or sacrificing some of the dovetail angle to get clearance from the bottom.

In my case, I would also be lacking some of the hardware to do custom rollers. The bearings used in the normal v-slot rollers are different to the 608 ones I have so I'd either need to print custom offsets (a pair of spacers, one of which has an offset hole for adjustment) for the rollers as well or buy some of the smaller bearings and use the existing offsets. I just whipped this up over Friday evening and Saturday afternoon and I'm the impatient type so don't like to wait for parts to arrive :mrgreen:

You could 3D print a custom plate for the XY thing as you suggest but it's kind of a waste of money at that point as you're then trying to adapt a solution to one problem to another. I'd also not trust a 3D printed plate as much as an optical breadboard for holding things like flashes at extreme angles and the threads can wear out pretty quick. I suppose brass inserts are a solution but by this point I'm 100% sure there's a better pre-made solution than the XY table and it also goes back to saving some money and designing something to your needs - a key one here was the low profile as I sometimes found I needed an extra few centimetres and didn't want to adjust other components to get it. Plus, it's way more enjoyable to make something yourself!
- Cam

RobertOToole
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Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by RobertOToole »

Hi Cam,

Thanks for getting me motived to finish some of my projects. Seeing your XT66 reminds me about my Thorlabs X95 rail vertical setup I have sitting here gathering dust unfinished. I'm planning in using a Velmex Unislide XY for positioning, 6 inch XY, 4 inch XY and 1.5 inch XY (I've been patient waiting for good buys on eBay).

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Hi Lothar,

I really like the type of XY with the concentric knob you are using on your setup. I ended up getting one as part of a Semprex stand and I never know what I was missing. You can reach over and easily dial in any movement without evening taking your eye off the screen. Don't overlook this type of XY table if you are looking for a solution.

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I have a new view on unfinished projects. Last week I returned from a 20 day trip to Istanbul and on the second to the last day one of the family members had a ischemic stroke (clot type)! He survived and is doing better but it made me thing that life is too short to let projects go on for too long. I hate to burden my wife with my office full of gear if something happened to me.

Best,

Robert

kaleun96
Posts: 270
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by kaleun96 »

RobertOToole wrote:
Mon Oct 11, 2021 8:11 pm
Hi Cam,

Thanks for getting me motived to finish some of my projects. Seeing your XT66 reminds me about my Thorlabs X95 rail vertical setup I have sitting here gathering dust unfinished. I'm planning in using a Velmex Unislide XY for positioning, 6 inch XY, 4 inch XY and 1.5 inch XY (I've been patient waiting for good buys on eBay).

Best,

Robert
Thanks Robert! I've admired those Velmex slides since I saw them on your website, would love to get one some day. Over the past year and a half or so 95% of my macro photography has been either of ancient coins or out in the field so I'm finding it harder to justify spending the money on precision gear :cry:

But that's partly why I'm finding a 3D printer to be a godsend - when you're working below 2x, 3D printed parts are easily capable of the necessary tolerances. I think if I did get a Velmex slide, I would probably mount it to the top of this carriage and use the carriage screw as coarse adjustment and a Velmex slide or similar for fine adjustment.
- Cam

kaleun96
Posts: 270
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by kaleun96 »

Made some upgrades:
  • Improved the dovetail fit
  • Changed the rollers from the split-wheel design to a solid wheel for greater contact
  • Incorporated the block for the screw nut into the carriage
  • Changed from using an M8 threaded rod to an 8mm "acme" (ISO trapezoidal screw) rod
  • Added a second pillow block to support the rod and thus reduce friction at the screw nut
  • 3D printed some knobs with numbers around the circumference to help keep track of adjustments
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- Cam

joshmacro
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Joined: Thu Apr 23, 2020 5:25 pm
Location: New York

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by joshmacro »

Hi Cam. Your rail concept is great. I use an aluminum extrusion rig (15 series profile) and your rail should be able to be adapted to my set-up. Can you please describe more the hardware for the rail? Also, what is travel per turn of the knob?

Thanks.

Josh

elf
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Joined: Sun Nov 18, 2007 12:10 pm

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by elf »

You can get T8 leadscrews with pitches between 1mm and 14mm. Anti-backlash nuts are also available. I can't measure any backlash on mine.

kaleun96
Posts: 270
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by kaleun96 »

joshmacro wrote:
Wed Oct 20, 2021 6:25 pm
Hi Cam. Your rail concept is great. I use an aluminum extrusion rig (15 series profile) and your rail should be able to be adapted to my set-up. Can you please describe more the hardware for the rail? Also, what is travel per turn of the knob?

Thanks.

Josh
Hey Josh! Is 15 series similar to v-slot aluminium extrusion but just different dimensions? If so you might be able to use some existing carriages, there are plenty for the 20mm v-slot extrusion (for example) so I imagine there are also some for 15 series extrusion. That might be precise enough for your needs in combination with an acme lead screw.

Hardware:
- 2x 608 bearings, which fit 8mm threaded rod near-perfectly
- Roller/wheel bearings. These fit a 5mm bolt.
- Offset/eccentric spacers. You need two for a set of four wheels, both on the same side so you can adjust the fit of the wheels to the extrusion. I used two normal spacers on the other side but I can't seem to find them. You can use four eccentric spacers, one for each wheel, just might be harder to calibrate the fit since you have four independent wheels to align.
- T8 lead screw with 2mm pitch
- Mounting nut for lead screw
- 2x Clamping ring for lead screw.

So I have 608 bearings at each end in "pillow blocks" to allow the screw to turn freely. On the first pillow block, I have the two clamping rings on either side to prevent the lead screw from moving, which forces the lead screw to move the carriage assembly instead. The carriage assembly has the mounting nut attached to it and the four roller wheels that are guided by the extrusion as well as the dovetail fit. As this lead screw is 2mm pitch, it moves 2mm for every turn and the backlash is not bad at all - much less than I got from a regular M8 threaded rod. You could add a anti-backlash nut to reduce any backlash though but for my needs it wasn't necessary.
- Cam

joshmacro
Posts: 82
Joined: Thu Apr 23, 2020 5:25 pm
Location: New York

Re: 3d Printed Carriage for Thorlabs XT66 optical rail

Post by joshmacro »

Hi Cam. Yes, 15 series is 1.5" v-slot aluminum extrusion. I have seen carriages such as the one you reference, but a rail like yours would be great to combine with it. A carriage is at least a start I guess. I appreciate you listing your hardware. Thanks a lot.
Josh

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