Acrylic tube cut to size is an ordering problem before it is a machining problem. A display fabricator ordered 300 acrylic tubes, 40 mm outside diameter, 900 mm long, and specified the inside diameter because that was the dimension on the drawing he had been given. Eleven per cent of the tubes would not accept the fitting. The wall thickness tolerance had done what wall thickness tolerance does.
Acrylic tube cut to size: three numbers in order
Outside diameter, wall thickness, length. That order matters because diameter is the dimension that locates the tube, wall is the dimension that carries the load, and length is the one that can be adjusted on site.
Specifying inside diameter moves the tolerance onto the wrong feature. A 50 mm tube with a 3 mm wall can arrive with a 43.6 mm bore, and a fitting designed for 44 mm will not pass.
The diameter and wall range that is actually stocked
- 20 to 60 mm: extruded, tight tolerance, widely stocked
- 60 to 200 mm: cast or extruded, stocked in increments of 5 to 10 mm
- 200 to 400 mm: cast, made to order, longer lead time
- 400 to 600 mm and above: cast only, quotation by drawing
Wall thickness is normally 1.5 to 10 mm, with 2 to 5 mm covering most display, lighting and furniture work. Above 10 mm the tube becomes a special casting.
Cutting length and what tolerance to expect
A saw cut holds plus or minus 0.3 mm on lengths up to a metre, and plus or minus 0.8 mm beyond that. For a tube that sits between two fixed points, order 1 mm long and trim on site rather than ordering to the millimetre and discovering a stack-up.
Squareness is the second tolerance: an end that is 0.5 mm out of square over a 50 mm diameter will not bond cleanly and shows a gap under light.
End finishing options
Three levels, priced accordingly: as-cut with a deburr, machined square, and machined square with a flame or vapour polish. The last is what a retail display needs, because a visible end is part of the product.
For tube that will be bonded into an assembly, machined square is the minimum. Solvent cement needs a flat, parallel face to capillary properly, and an out-of-square end leaves a void that shows as a white line.
Packing and the ovality problem
Tube is easily distorted in transit. Long lengths stacked without internal support arrive slightly oval, and an oval tube will not accept a round fitting. Packing in a crate with end supports, or in bundles with a mandrel, prevents it.
Inspect three tubes per bundle for ovality at arrival. A caliper across two axes takes seconds and catches a whole bundle.
For diameters above 200 mm, price and lead time shift because the tube is cast to order; the large diameter tube note covers the sizing and quotation convention. For structural uses, the tube strength guide gives the wall thickness logic.
Send a diameter, wall and length list to oversales@rpplexiglass.com; we will confirm stock sizes and cut tolerance before the order.
Frequently Asked Questions
What diameters are available in acrylic tube?
Cast tube commonly runs from 20 mm to 600 mm outside diameter, with larger sizes made to order. Extruded tube covers the smaller range with tighter dimensional consistency.
How is acrylic tube wall thickness specified?
By outside diameter and wall, for example 50 mm outside diameter with a 3 mm wall. Stating inside diameter instead causes most ordering errors, because wall tolerance then moves the fit.
Can tube ends be finished square?
Yes: saw cut then machined or polished square to within 0.2 mm over the diameter. A hand-cut end is visibly out of square and will not bond cleanly.