Oval duct transition fitting / hose-shaped reducer 3D models

First model: 2025-12-03

Number of 3D models generated: 114

Category: technical parts

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Photos of various 3D printed models

This template generates oval duct adapters, similar to hose-like connectors.

Depending on whether you print the fitting in a rigid material (PLA, PETG, ABS, ASA) or a flexible one (TPU, TPC), you’ll end up with different possible uses.

With more than ten parameters — including offsets along the Y and Z axes — this template can accommodate a wide range of situations. By setting the width just slightly greater than the height (example: width = 90.1, height = 90), you can create a near-circular tube on one side or both sides of the adapter.

You can also add internal or external chamfers to make assembly easier.

Most models print without supports.

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Keywords: oval transition fitting, oval duct fitting, oval adapter, oval duct adapter, oval transition, oval reducer, oval coupling, oval transition coupling, oval joint, oval end fitting, oval connector part, oval hose adapter, oval hose fitting, oval hose piece, ovoid fitting, ovoid adapter

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	name	unit	Value	Weight
#1	side A internal width 10 to 300 – up to 1 decimal place	mm
#2	side A internal height 10 to 300 – up to 1 decimal place	mm
#3	sleeve length on side A 5 to 100 – up to 1 decimal place	mm
#4	side B internal width 10 to 300 – up to 1 decimal place	mm
#5	side B internal height 10 to 300 – up to 1 decimal place	mm
#6	sleeve length on side B 5 to 100 – up to 1 decimal place	mm
#7	thickness 1 to 8 - integer	mm
#8	transition length 20 to 300 – up to 1 decimal place	mm
#9	Y offset 0 to 300 – up to 1 decimal place	mm
#10	Z offset 0 to 300 – up to 1 decimal place	mm
#11	end chamfers		-	-
			Search

Illustration of the parameters

The latest online-generated models

Oval duct transition adapter STL 3D file 215x90 mm to 150x149.8 mm – transition: 20 mm (📦 #11306)

1 object(s) - format STL

Oval connector in STL 3D file format. The internal cross-section on side A is 215x90 mm (oval), while on side B it is 150x149.8 mm (nearly circular). Each sleeve provides a useful length of 20 mm. The transition section between the two ends is 20 mm long, for an overall length of 60 mm (sleeve A, transition and sleeve B). The external chamfers improve fit when inserting the adapter into ducts or hoses.

Parameter	Value	Unit
side A internal width	215	mm
side A internal height	90	mm
sleeve length on side A	20	mm
side B internal width	150	mm
side B internal height	149.8	mm
sleeve length on side B	20	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Hose-shaped reducer STL file 215x90 mm to 150x149.8 mm – transition: 20 mm (📦 #11305)

1 object(s) - format STL

Oval adapter available as a STL 3D file. On side A, the internal cross-section is 215x90 mm (oval), whereas on side B it is 150x149.8 mm (nearly circular). On side A, the sleeve is 20 mm long, and on side B 10 mm. The central transition occupies 20 mm, bringing the overall length to 50 mm. External chamfers are added at the ends to make it easier to insert the adapter into ducts or hoses.

Parameter	Value	Unit
side A internal width	215	mm
side A internal height	90	mm
sleeve length on side A	20	mm
side B internal width	150	mm
side B internal height	149.8	mm
sleeve length on side B	10	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Oval duct transition adapter STL 3D file 210x71 mm to 135x134 mm – transition: 20 mm (📦 #11278)

1 object(s) - format STL

Oval hose adapter in STL 3D file format. The internal cross-section on side A is 210x71 mm (oval), while on side B it is 135x134 mm (nearly circular). On side A, the sleeve is 20 mm long, and on side B 100 mm. Between the two sleeves, the transition runs over 20 mm, resulting in an overall length of 140 mm. A thickness of 1 mm provides a very light, thin shell. Internal chamfers are added at the ends to make assembly and duct insertion easier.

Parameter	Value	Unit
side A internal width	210	mm
side A internal height	71	mm
sleeve length on side A	20	mm
side B internal width	135	mm
side B internal height	134	mm
sleeve length on side B	100	mm
thickness	1	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval duct transition fitting STL 3D file 69x39 mm to 70x69 mm – transition: 30 mm (📦 #11164)

1 object(s) - format STL

Oval duct fitting in STL 3D file format. The internal cross-section on side A is 69x39 mm (oval), while on side B it is 70x69 mm (nearly circular). The useful sleeve length on side A is 20 mm, while on side B it reaches 10 mm. The transition section is 30 mm long, for a final overall length of 60 mm. The ends are straight, with no chamfer at all.

Parameter	Value	Unit
side A internal width	69	mm
side A internal height	39	mm
sleeve length on side A	20	mm
side B internal width	70	mm
side B internal height	69	mm
sleeve length on side B	10	mm
thickness	3	mm
transition length	30	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval duct transition fitting STL 3D file 67x46 mm to 67.1x67 mm – transition: 20 mm (📦 #11099)

1 object(s) - format STL

STL 3D file for an oval adapter. The internal cross-section on side A is 67x46 mm (oval), while on side B it is 67.1x67 mm (nearly circular). Both sleeves share an identical useful length of 8 mm. The transition links the two ends over 20 mm, with a total overall length of 36 mm. Both the inner and outer edges at the ends remain unchamfered.

Parameter	Value	Unit
side A internal width	67	mm
side A internal height	46	mm
sleeve length on side A	8	mm
side B internal width	67.1	mm
side B internal height	67	mm
sleeve length on side B	8	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval duct transition adapter STL 3D file 67x46 mm to 67.1x67 mm – transition: 20 mm (📦 #11094)

1 object(s) - format STL

Oval duct fitting provided as a STL 3D file. The internal cross-section on side A is 67x46 mm (oval), while on side B it is 67.1x67 mm (nearly circular). A uniform useful length of 14 mm is available on both sleeves. The transition links the two ends over 20 mm, with a total overall length of 48 mm. No chamfer is applied at the ends, so both the inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	67	mm
side A internal height	46	mm
sleeve length on side A	14	mm
side B internal width	67.1	mm
side B internal height	67	mm
sleeve length on side B	14	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval duct transition fitting STL file 52.5x22.7 mm to 52.5x22.7 mm – transition: 35.5 mm (📦 #11030)

1 object(s) - format STL

Oval duct transition adapter available as a STL 3D file. Both ends share the same internal cross-section, 52.5x22.7 mm. A uniform useful length of 30 mm is available on both sleeves. The transition section is 35.5 mm long, for a final overall length of 95.5 mm. Wall thickness is minimal at 1 mm. The internal chamfers help start the duct insertion more easily.

Parameter	Value	Unit
side A internal width	52.5	mm
side A internal height	22.7	mm
sleeve length on side A	30	mm
side B internal width	52.5	mm
side B internal height	22.7	mm
sleeve length on side B	30	mm
thickness	1	mm
transition length	35.5	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval hose adapter STL 3D file 52.5x22.7 mm to 52.5x22.7 mm – transition: 35 mm (📦 #11027)

1 object(s) - format STL

Oval duct coupling available as a STL 3D file. Both ends share the same internal cross-section, 52.5x22.7 mm. Each sleeve provides a useful length of 30 mm. The central transition occupies 35 mm, bringing the overall length to 95 mm. With 1 mm of thickness, the wall remains flexible and material-efficient. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	52.5	mm
side A internal height	22.7	mm
sleeve length on side A	30	mm
side B internal width	52.5	mm
side B internal height	22.7	mm
sleeve length on side B	30	mm
thickness	1	mm
transition length	35	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval duct transition adapter STL file 26x17 mm to 26x17 mm – transition: 20 mm (📦 #10878)

1 object(s) - format STL

Oval hose adapter provided as a STL 3D file. The internal cross-sections on sides A and B are identical, 26x17 mm. The useful sleeve length is the same on both sides, 20 mm. The transition section is 20 mm long, for a final overall length of 60 mm. The internal edges at the ends are chamfered to help guide the duct during insertion. Compared to side A, side B is shifted by 1.3 mm along the Y axis and 8.5 mm along the Z axis.

Parameter	Value	Unit
side A internal width	26	mm
side A internal height	17	mm
sleeve length on side A	20	mm
side B internal width	26	mm
side B internal height	17	mm
sleeve length on side B	20	mm
thickness	3	mm
transition length	20	mm
Y offset	1.3	mm
Z offset	8.5	mm
end chamfers	inside

Oval duct transition fitting STL file 67x47 mm to 55x35 mm – transition: 90 mm (📦 #10860)

1 object(s) - format STL

STL 3D file for an oval pipe adapter. Side A offers an internal cross-section of 67x47 mm and side B 55x35 mm. A uniform useful length of 10 mm is available on both sleeves. The central transition occupies 90 mm, bringing the overall length to 110 mm. The ends are left without chamfers, with raw inner and outer edges.

Parameter	Value	Unit
side A internal width	67	mm
side A internal height	47	mm
sleeve length on side A	10	mm
side B internal width	55	mm
side B internal height	35	mm
sleeve length on side B	10	mm
thickness	2	mm
transition length	90	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval duct transition adapter STL 3D file 63x47 mm to 53x37 mm – transition: 110 mm (📦 #10859)

1 object(s) - format STL

Oval adapter available as a STL 3D file. Side A offers an internal cross-section of 63x47 mm and side B 53x37 mm. Both sleeves share an identical useful length of 5 mm. Between the two sleeves, the transition runs over 110 mm, resulting in an overall length of 120 mm. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	63	mm
side A internal height	47	mm
sleeve length on side A	5	mm
side B internal width	53	mm
side B internal height	37	mm
sleeve length on side B	5	mm
thickness	2	mm
transition length	110	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval duct transition adapter STL 3D file 73x30 mm to 65x35 mm – transition: 150 mm (📦 #10814)

1 object(s) - format STL

Oval duct transition adapter in STL 3D file format. The internal cross-section on side A is 73x30 mm, while on side B it is 65x35 mm. The useful lengths are 30 mm (A) and 50 mm (B), respectively. The transition section between the two ends is 150 mm long, for an overall length of 230 mm (sleeve A, transition and sleeve B). The external edges at the ends are chamfered, which simplifies inserting the adapter into the duct.

Parameter	Value	Unit
side A internal width	73	mm
side A internal height	30	mm
sleeve length on side A	30	mm
side B internal width	65	mm
side B internal height	35	mm
sleeve length on side B	50	mm
thickness	2	mm
transition length	150	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Oval duct transition adapter STL 3D file 110.1x110 mm to 180x40 mm – transition: 70 mm (📦 #10650)

1 object(s) - format STL

Oval duct adapter provided as a STL 3D file. On side A, the internal cross-section is 110.1x110 mm (nearly circular), whereas on side B it is 180x40 mm (oval). The sleeves on sides A and B have the same useful length of 40 mm. The central transition occupies 70 mm, bringing the overall length to 150 mm. External chamfers at the ends help with engagement and assembly within the duct system. Compared to side A, side B is shifted by 35 mm along the Y axis.

Parameter	Value	Unit
side A internal width	110.1	mm
side A internal height	110	mm
sleeve length on side A	40	mm
side B internal width	180	mm
side B internal height	40	mm
sleeve length on side B	40	mm
thickness	2	mm
transition length	70	mm
Y offset	35	mm
Z offset	0	mm
end chamfers	outside

Oval duct transition adapter STL 3D file 110.1x110 mm to 180x40 mm – transition: 20 mm (📦 #10649)

1 object(s) - format STL

STL 3D file for an oval duct adapter. On side A, the internal cross-section is 110.1x110 mm (nearly circular), whereas on side B it is 180x40 mm (oval). A uniform useful length of 40 mm is available on both sleeves. The transition portion extends over 20 mm and the overall length, sleeves included, is 100 mm. External chamfers at the ends help with engagement and assembly within the duct system.

Parameter	Value	Unit
side A internal width	110.1	mm
side A internal height	110	mm
sleeve length on side A	40	mm
side B internal width	180	mm
side B internal height	40	mm
sleeve length on side B	40	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Oval hose adapter STL file 110.1x110 mm to 180x40 mm – transition: 70 mm (📦 #10648)

1 object(s) - format STL

Oval adapter provided as a STL 3D file. The internal cross-section on side A is 110.1x110 mm (nearly circular), while on side B it is 180x40 mm (oval). The useful length is consistent on both ends: 40 mm. Between the two sleeves, the transition runs over 70 mm, resulting in an overall length of 150 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier. Side B is offset by 35 mm along the Z axis relative to side A.

Parameter	Value	Unit
side A internal width	110.1	mm
side A internal height	110	mm
sleeve length on side A	40	mm
side B internal width	180	mm
side B internal height	40	mm
sleeve length on side B	40	mm
thickness	2	mm
transition length	70	mm
Y offset	0	mm
Z offset	35	mm
end chamfers	inside

Oval hose adapter STL file 110.1x110 mm to 180x40 mm – transition: 70 mm (📦 #10646)

1 object(s) - format STL

STL 3D file for an oval adapter. Side A offers an internal cross-section of 110.1x110 mm (nearly circular) and side B 180x40 mm (oval). Both sleeves share an identical useful length of 40 mm. The transition links the two ends over 70 mm, with a total overall length of 150 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier. An offset of 35 mm along the Y axis and 35 mm along the Z axis is applied to side B relative to side A.

Parameter	Value	Unit
side A internal width	110.1	mm
side A internal height	110	mm
sleeve length on side A	40	mm
side B internal width	180	mm
side B internal height	40	mm
sleeve length on side B	40	mm
thickness	2	mm
transition length	70	mm
Y offset	35	mm
Z offset	35	mm
end chamfers	inside

Oval duct transition adapter STL 3D file 25.6x15.7 mm to 11x10 mm – transition: 160 mm (📦 #10315)

1 object(s) - format STL

STL 3D file for an oval duct adapter. On side A, the internal cross-section is 25.6x15.7 mm, whereas on side B it is 11x10 mm. The sleeves on sides A and B have the same useful length of 19.6 mm. Between the two sleeves, the transition runs over 160 mm, resulting in an overall length of 199.2 mm. The external edges at the ends are chamfered, which simplifies inserting the adapter into the duct.

Parameter	Value	Unit
side A internal width	25.6	mm
side A internal height	15.7	mm
sleeve length on side A	19.6	mm
side B internal width	11	mm
side B internal height	10	mm
sleeve length on side B	19.6	mm
thickness	2	mm
transition length	160	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Hose-shaped reducer STL 3D file 200x75 mm to 111x110 mm – transition: 60 mm (📦 #10294)

1 object(s) - format STL

Oval connector available as a STL 3D file. On side A, the internal cross-section is 200x75 mm (oval), whereas on side B it is 111x110 mm (nearly circular). A uniform useful length of 50 mm is available on both sleeves. Between the two sleeves, the transition runs over 60 mm, resulting in an overall length of 160 mm. A thickness of 1 mm provides a very light, thin shell. The internal edges at the ends are chamfered to help guide the duct during insertion. An offset of 30 mm along the Z axis is applied to side B relative to side A.

Parameter	Value	Unit
side A internal width	200	mm
side A internal height	75	mm
sleeve length on side A	50	mm
side B internal width	111	mm
side B internal height	110	mm
sleeve length on side B	50	mm
thickness	1	mm
transition length	60	mm
Y offset	0	mm
Z offset	30	mm
end chamfers	inside

Oval duct transition fitting STL 3D file 200x75 mm to 111x110 mm – transition: 60 mm (📦 #10293)

1 object(s) - format STL

Oval pipe adapter provided as a STL 3D file. Side A offers an internal cross-section of 200x75 mm (oval) and side B 111x110 mm (nearly circular). The sleeves on sides A and B have the same useful length of 50 mm. The transition portion extends over 60 mm and the overall length, sleeves included, is 160 mm. Internal chamfers at the ends improve assembly and make insertion smoother. Side B is offset by 30 mm along the Z axis relative to side A.

Parameter	Value	Unit
side A internal width	200	mm
side A internal height	75	mm
sleeve length on side A	50	mm
side B internal width	111	mm
side B internal height	110	mm
sleeve length on side B	50	mm
thickness	2	mm
transition length	60	mm
Y offset	0	mm
Z offset	30	mm
end chamfers	inside

Oval duct transition adapter STL 3D file 218x93 mm to 215x90 mm – transition: 20 mm (📦 #10236)

1 object(s) - format STL

Oval connector available as a STL 3D file. Side A offers an internal cross-section of 218x93 mm and side B 215x90 mm. Each sleeve provides a useful length of 10 mm. Between the two sleeves, the transition runs over 20 mm, resulting in an overall length of 40 mm. The internal chamfers help start the duct insertion more easily.

Parameter	Value	Unit
side A internal width	218	mm
side A internal height	93	mm
sleeve length on side A	10	mm
side B internal width	215	mm
side B internal height	90	mm
sleeve length on side B	10	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval hose adapter STL file 190x165 mm to 135x35 mm – transition: 45 mm (📦 #9931)

1 object(s) - format STL

Oval connector available as a STL 3D file. On side A, the internal cross-section is 190x165 mm, whereas on side B it is 135x35 mm. The sleeves also differ in useful length: 30 mm on side A and 45 mm on side B. The transition links the two ends over 45 mm, with a total overall length of 120 mm. The shell is relatively thick, with a wall thickness of 5 mm. External chamfers are added at the ends to make it easier to insert the adapter into ducts or hoses.

Parameter	Value	Unit
side A internal width	190	mm
side A internal height	165	mm
sleeve length on side A	30	mm
side B internal width	135	mm
side B internal height	35	mm
sleeve length on side B	45	mm
thickness	5	mm
transition length	45	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Hose-shaped reducer STL file 88.9x34.9 mm to 46x45 mm – transition: 20 mm (📦 #9872)

1 object(s) - format STL

STL 3D file for an oval connector. On side A, the internal cross-section is 88.9x34.9 mm (oval), whereas on side B it is 46x45 mm (nearly circular). The useful length is consistent on both ends: 10 mm. The transition links the two ends over 20 mm, with a total overall length of 40 mm. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	88.9	mm
side A internal height	34.9	mm
sleeve length on side A	10	mm
side B internal width	46	mm
side B internal height	45	mm
sleeve length on side B	10	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval duct transition fitting STL file 50x20 mm to 35.6x35.5 mm – transition: 20 mm (📦 #9780)

1 object(s) - format STL

Oval duct adapter provided as a STL 3D file. Side A offers an internal cross-section of 50x20 mm (oval) and side B 35.6x35.5 mm (nearly circular). On side A, the sleeve is 20 mm long, and on side B 35 mm. The transition section between the two ends is 20 mm long, for an overall length of 75 mm (sleeve A, transition and sleeve B). The external chamfers improve fit when inserting the adapter into ducts or hoses.

Parameter	Value	Unit
side A internal width	50	mm
side A internal height	20	mm
sleeve length on side A	20	mm
side B internal width	35.6	mm
side B internal height	35.5	mm
sleeve length on side B	35	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Hose-shaped reducer STL 3D file 140x139 mm to 250x20 mm – transition: 75 mm (📦 #9613)

1 object(s) - format STL

STL 3D file for an oval pipe adapter. The internal cross-section on side A is 140x139 mm (nearly circular), while on side B it is 250x20 mm (oval). On side A, the sleeve is 50 mm long, and on side B 100 mm. Between the two sleeves, the transition runs over 75 mm, resulting in an overall length of 225 mm. The ends are straight, with no chamfer at all.

Parameter	Value	Unit
side A internal width	140	mm
side A internal height	139	mm
sleeve length on side A	50	mm
side B internal width	250	mm
side B internal height	20	mm
sleeve length on side B	100	mm
thickness	3	mm
transition length	75	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Hose-shaped reducer STL file 145x144 mm to 250x20 mm – transition: 75 mm (📦 #9611)

1 object(s) - format STL

STL 3D file for an oval duct transition adapter. On side A, the internal cross-section is 145x144 mm (nearly circular), whereas on side B it is 250x20 mm (oval). On side A, the sleeve is 50 mm long, and on side B 100 mm. The transition section between the two ends is 75 mm long, for an overall length of 225 mm (sleeve A, transition and sleeve B). The shell is relatively thick, with a wall thickness of 4 mm. Both the inner and outer edges at the ends remain unchamfered.

Parameter	Value	Unit
side A internal width	145	mm
side A internal height	144	mm
sleeve length on side A	50	mm
side B internal width	250	mm
side B internal height	20	mm
sleeve length on side B	100	mm
thickness	4	mm
transition length	75	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval hose adapter STL file 145x144 mm to 250x20 mm – transition: 60 mm (📦 #9610)

1 object(s) - format STL

Oval adapter in STL 3D file format. Side A offers an internal cross-section of 145x144 mm (nearly circular) and side B 250x20 mm (oval). You get a sleeve of 70 mm on side A and 100 mm on side B. The central transition occupies 60 mm, bringing the overall length to 230 mm. A thickness of 4 mm provides good stiffness. The ends are straight, with no chamfer at all.

Parameter	Value	Unit
side A internal width	145	mm
side A internal height	144	mm
sleeve length on side A	70	mm
side B internal width	250	mm
side B internal height	20	mm
sleeve length on side B	100	mm
thickness	4	mm
transition length	60	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval duct transition fitting STL file 150x149 mm to 250x20 mm – transition: 40 mm (📦 #9609)

1 object(s) - format STL

Oval duct coupling available as a STL 3D file. The internal cross-section on side A is 150x149 mm (nearly circular), while on side B it is 250x20 mm (oval). The sleeves also differ in useful length: 50 mm on side A and 100 mm on side B. The transition section is 40 mm long, for a final overall length of 190 mm. With 4 mm of wall thickness, the adapter gains extra strength. The ends are left without chamfers, with raw inner and outer edges.

Parameter	Value	Unit
side A internal width	150	mm
side A internal height	149	mm
sleeve length on side A	50	mm
side B internal width	250	mm
side B internal height	20	mm
sleeve length on side B	100	mm
thickness	4	mm
transition length	40	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval hose adapter STL file 121x120.5 mm to 90x53 mm – transition: 63 mm (📦 #9581)

1 object(s) - format STL

Oval coupling in STL 3D file format. On side A, the internal cross-section is 121x120.5 mm (nearly circular), whereas on side B it is 90x53 mm (oval). The sleeve on side A provides a useful length of 25 mm, and on side B 30 mm. The transition section is 63 mm long, for a final overall length of 118 mm. Internal chamfers at the ends improve assembly and make insertion smoother. An offset of 31.5 mm along the Z axis is applied to side B relative to side A.

Parameter	Value	Unit
side A internal width	121	mm
side A internal height	120.5	mm
sleeve length on side A	25	mm
side B internal width	90	mm
side B internal height	53	mm
sleeve length on side B	30	mm
thickness	2	mm
transition length	63	mm
Y offset	0	mm
Z offset	31.5	mm
end chamfers	inside

Oval duct transition adapter STL 3D file 77x75 mm to 60x55 mm – transition: 50 mm (📦 #9178)

1 object(s) - format STL

Oval adapter available as a STL 3D file. The internal cross-section on side A is 77x75 mm (nearly circular), while on side B it is 60x55 mm (oval). The useful sleeve length on side A is 50 mm, while on side B it reaches 100 mm. Between the two sleeves, the transition runs over 50 mm, resulting in an overall length of 200 mm. The wall is on the thicker side at 4 mm. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	77	mm
side A internal height	75	mm
sleeve length on side A	50	mm
side B internal width	60	mm
side B internal height	55	mm
sleeve length on side B	100	mm
thickness	4	mm
transition length	50	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Oval duct transition adapter STL 3D file 66x65.9 mm to 107x51.5 mm – transition: 20 mm (📦 #8831)

1 object(s) - format STL

STL 3D file for an oval coupling. The internal cross-section on side A is 66x65.9 mm (nearly circular), while on side B it is 107x51.5 mm (oval). The sleeves on sides A and B have the same useful length of 80 mm. Between the two sleeves, the transition runs over 20 mm, resulting in an overall length of 180 mm. The wall is on the thicker side at 5 mm. The ends are straight, with no chamfer at all.

Parameter	Value	Unit
side A internal width	66	mm
side A internal height	65.9	mm
sleeve length on side A	80	mm
side B internal width	107	mm
side B internal height	51.5	mm
sleeve length on side B	80	mm
thickness	5	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Oval Duct Transition Fittings

Oval duct transition fittings are designed to connect two oval sections with different dimensions or slight misalignment while maintaining a clean, accurate fit. These custom 3D-printed parts could be suitable for HVAC setups, air-handling systems, workshop projects, and any situation where a precise geometry is required. Their parametric design ensures a stable, reliable connection, especially in tight installations or when working with flexible hose-style conduits, as shown with this hose-type connector.

Several profiles can be generated depending on the application: a standard oval-to-oval transition to extend or adapt an existing duct, an offset version to compensate for centerline shifts, or a progressive reducer for smoother airflow between different cross-sections. Although primarily intended for oval transitions, this template can also produce round-to-oval adapters by tuning the dimensions precisely, as demonstrated by this round-to-oval transition. These models could also help create vent register adapters, such as this vent outlet adapter.

Every fitting is fully configurable: sleeve length, wall thickness, dimensions of both ends, offsets, and optional chamfers for easier assembly. This level of customization makes it possible to produce parts that deliver a clean and reliable transition and remain straightforward to 3D-print, whether for a technical setup, a prototype, or a practical everyday project.