Folgertech FT-5 Y Idler upgrade

by Fiskauto, published

Folgertech FT-5 Y Idler upgrade by Fiskauto Feb 14, 2017

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This is a more robust design of the Folgertech FT-5 Y idler assembly using more commonly acquired 608 bearings also widely used as skateboard bearings designed to be a drop in modular assembly for the originally equipped components. Feedback positive or negative is always welcomed and encouraged "of course if tastefully spoken" as that is how we all learn. If this works for you please show it off by posting a make of it as it is what keeps inspired to do more. If for some reason it doesn't, please let me know and I'll do what I need to to make it work. Thanks to John Folger for the awesome machine he has made so affordable everyone should own one!

Print Settings


Folgertech FT-5






I used .2 layer height


I used 20% but recommend 50% and up.


Parts are designed to have the halves mating flanges as flat as possible so orient the lower half upside down so it is touching the bed. Recommend printing in ABS or higher temperature and strength materials especially if using with a heated build chamber.


Assembly instructions and bill of materials to follow

Parts list

4-608 bearings 8x22x7 commonly used for skateboards.

2-m8 smooth rod x 34mm long. Chamfer both ends for idler axle shaft. Pretty much any type will work.

2-GT2 20 tooth X 8mm pulleys with set screws. https://www.amazon.com/gp/aw/d/B019GIJ296/ref=mp_s_a_1_1?ie=UTF8&qid=1496123258&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=gt2%2B20t%2B8mm%2Bpulley&dpPl=1&dpID=51s-XR%2B4CcL&ref=plSrch&th=1&psc=1

8-m5 x 16 hex head cap screws to replace existing y idler plate screws too short for this use.

8-existing m5 drop in t-nuts.

Perform post printing clean-up of support as necessary. Press a bearing into each top cap and into lower base bearing seats. Loosen Y motor bolts to release belt and remove both existing Y idler top plates and idlers. Remove and reuse the 8 t-nuts. Store away remaining existing parts in a safe place in case this doesn't work. Haha. Prepare top plates by installing m5 x 16 socket head cap screws down through each one. Thread the loop of belt through the opening in each respective Y base while observing proper right/left side orientation. Insert m6 smooth rod axle down through belt loop and into lower bearing being careful not to push the shaft to far or the bearing out of the lower base. Insert the pulley down through the belt loop onto the axle shaft being sure to observe the top to bottom orientation of the pulley. The large pulley body end with the retainer screws should go up. While holding the lower shaft end and bearing in place, install upper cap down onto the axle shaft until base and cap flanges meet. Push all m5 cap screws through the cap and base and loosely install the drop in t-nuts. To ease installation, hold body together and move axle shaft if necessary to be approximately 1 mm above bottom base. Let pulley seat against lower brearing and lightly tighten one of the pulley set screws. Now align all the t-nuts in orientation to the slots in the extrusion and set body down on place. Be sure body is seated flat against all the extrusions and then do the wiggle jiggle twist procedure we're all familiar with to get the t-nuts to seat. I found it is best and easier to lock the front rail screws first. Once solidly locked down, adjust your belt tension and lock your motor screws. Loosen the pulley set screw that you lightly tightened. Next slide the gantry back and forth a few times to center the pulley and belt to pulley. When happy with what it is doing, center a set screw in the set screw window and tighten firmly. Move the gantry to the next screw and also tighten firmly. Check your work and movement of the gantry. Done! Have a beer or drink of choice. On to X

How I Designed This

Designed to be a drop in replacements for the orignal y idlers.

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Should to bearing be held by the lower piece or sit down to the base of the upper base plate?
Just looking at how this goes together and a little confused how the lower bearing sits in the Lower.
Top fits just fine

Not entirely sure I understand your question. Could you explain further?

In the bottom piece of each idler...should the 608 bearing sit in the idler piece? It looks to sit within the confines of it, but the piece looked concave, as if to hold the bottom of the 608 bearing? (It appears the bearings sit on top of the FT-17 and FT-18 upper panels)

Let me further clarify...lower bearing seats...my lower bearing falls through.

It doesn't lay on the melamine under it? It should be a press fit but was also designed so that the lower melamine piece would also hold it in place. I did that so nobody would have to deal with the bridging of the lower circle which would be at the top when printing in correct orientation. Hope this helps but if not, ask away.

Thanks Fiskauto. I just assumed (wrongly) that the design was also meant for the driver side.

Excellent design!
I'm probably missing something obvious. But...how do you mate the motor shaft (3mm) to the 8mm pulley ?
3 to 8mm coupling ?

It doesn't actually mate with a motor shaft. It requires an axle made of 8mm or 5/16 rod cut to size. The 8 mm rod fits the bearing center holes and will fit inside the GT2 20 tooth 8 mm center pulley that is also required. Hopefully this helps. If not, comment back.

Nice robust design!
But did I assemble something wrong if the parts don't fit between the 2020 extrusion, on either side?
Mechanics of the printer seem fine.

Am not sure. Haven't had any concerns on fitment yet. Could you somehow send me a picture of the fitment issue and I can see what you're up against?

I have the same issue, I printed the Y idler upgrade and the bearing sat in the part well, but I then printed these parts and the flanged bearing will no go deep enough since the recess is more of a bevel, not letting it sit right, heres a pic of them side by side https://www.instagram.com/p/BWyL-ELlvjc/

I'm sorry. Been so long since I put the together I had to take a look at the design. Those flanges that hang out are supposed to fit in the hole of the lower Y body to properly center it. They should interference fit into the lower body. Have you tried putting them together yet?

Yes I have, the flange will not fit in the hole, I tried reversing it and it won't even go is so I believe that the hole in this part is not enlarged to fit the flange

If it is just the groove that the flange goes down into the ones you printed should be able to be salvaged though it will mean using a Dremel tool to enlarge or deepen the grooves. Am not real sure what went wrong there. Haven't had any other complaints but only thing I can think is that your flanges are larger/thicker than the ones I used for the design.

LOL im starting to think everyone else used the "608ZZ and washer" method therefore doesn't see the issue, but I wanted to stay true and ordered the F608 since I liked the overall design

I actually thought of that possibility, that this version of the flange was too small, however, it fits perfectly flush in your X Idler upgrade

Let me see if we understand each other. The one single piece in the center of your photo, you say fits peoperly, correct? If so, that is the X idler and not the Y idler.

Thats correct, the X idler you modeled does indeed fit, its the Y idler that does not. I am very thankful for your response and are adamant about the feedback since I love this design =)

Well made part. Used 50% triangular infill in simipify 50mms print speed 150 degree print temp 70 degree bed temp in pctg. part is really rigid strong and bearings dropped right in nice and snug with no play or warpage. only weak to force up and down part is very strong under lateral forces it would normally endure. almost no post processing needed besides remove strings from overhang.

Thanks for the comments and critique. Am glad it worked well for you.

did you purchase a longer smooth rod and cut them to length or is there a supplier that sells the 34mm length rods

Dremel with a rotary metal wheel worked great.

Excellent, glad to hear!

I actually had some laying around from previous builds and mods that I cut to length. Am sure there are suppliers that would cut to length for you but would probably increase the price more than what it's worth. If you don't have a hacksaw or grinder to cut them and finish the ends, you might be able to visit a local hackerspace, makerspace or even your local auto shop could do it for you.

Suggestions on where to source the 8mm pulley and 16mm hex screws?

Amazon is best. 5 pack pulleys from seller Laptopaid is what I got. Search M3 x 16 on Amazon for the screws or you may be able to pick smaller quantity up at local HW store or Lowe's, Homedepot.

Thank you for the correction Ramon. That indeed should be search for m5x16 instead of m3x16 as I mistakingly replied in an earlier post. I believe the info is correct in the materials list.

cool just wanted to let you know