Custom machined part
Plastic insulating rings
- Breaks
- Electrical or heat paths
- Forms
- Rings, sleeves, washers & gaskets
- Made to
- Your drawing & grade
- Starting point
- Drawing, spec or old ring
Machined plastic rings, sleeves and washers that break an electrical or heat path at a joint or bore, made to your drawing and the grade your specification names.
- ±0.002"–±0.005" on critical dimensions
- Family owned in Aurora since 1986
- Expedited service for breakdowns
Where insulating rings are used
Three places a ring breaks a path
These are common settings, given for orientation. In each, the ring breaks a path while the assembly around it still carries the load.
Bolted flange
- What the ring does
- An isolating gasket between the flanges, with sleeves and washers around the bolts, so the flange and its fasteners don’t recreate a metal path.
- The honest limit
- Complete isolation kits can include metal parts and a separate seal. Pressure, sealing and protection performance belong to the kit design.
- We machine
- The plastic pieces your kit needs: gasket, sleeves, washers or rings, to your drawing and grade.
Bearing housing
- What the ring does
- An insulating sleeve or ring in the housing, one published way to stop shaft current passing through a bearing on drive-fed equipment.
- The honest limit
- Insulating one bearing doesn’t remove the shaft voltage. It can push the current into the next bearing, gearbox or encoder, so it belongs in a wider plan.
- We machine
- The sleeve or ring, machined to your housing bore and bearing size.
Heated joint
- What the ring does
- A ring or insert between a heated part and its support, to cut how much heat flows into the frame.
- The honest limit
- The result depends on the exact grade’s thermal data, the contact area, thickness and load. We don’t promise a temperature or an energy saving.
- We machine
- The ring or insert, machined to your fit in the grade your specification names.
What defines the ring
Sized to what it fits between
An insulating ring is sized to the parts it fits between. We machine it from your drawing, or from the old ring and the parts it fits.
- The ring
-
- ID and OD
- Thickness or length
- Shoulder or flange
- Split or grooves
- Bolt pattern or counterbore
- What it fits between
-
- Housing bore or bearing OD
- Flange and fastener sizes
- Mating materials
- The fits you need
- The duty
-
Electrical
- Voltage and frequency
- Creepage or clearance needed
- Electrical property and test method
- Grounding plan
- Flame or certification class
Flange
- Which kit pieces you need
- Clamp load
- Media, pressure and temperature
- Sealing role
Bearing
- Bearing OD and housing bore
- Drive setup
- Your shaft-current plan
Thermal
- Hot- and cold-side temperatures
- Duty cycle
- Contact area and load
- Target thermal requirement
Electrical and thermal ratings come from your exact grade, its thickness and your specification, not from the machining. Tell us the grade and any allowed substitutes.
Getting a quote
Start with what you have
Any one of these is enough to get a quote started. Pick yours to see what helps.
Send the drawing and the specification it calls up.
- The exact grade
- Allowed substitutes
- Test or documentation needs
Upload drawings, specifications and photos on the quote form.
Send the old ring and the parts it fits between.
- Its grade, if known
- What failed
- Quantity
A sample gives us the shape, not its original grade, rating or certification.
Send the joint sizes and the duty. We’ll ask for the rest.
- Mating sizes
- Electrical or thermal duty
- A photo of the joint
Upload drawings, specifications and photos on the quote form.
Plastics for insulating rings
Common grades for insulating rings
- G10 / FR4 Glass-epoxy laminate, a common electrical insulating grade.
- Phenolic Paper or fabric laminates for electrical and mechanical duty.
- PEEK Strong and stable at temperature.
- ULTEM High-temperature PEI with good electrical properties.
- PTFE Chemically inert, with a wide temperature range.
- Acetal Stiff and stable for lower-temperature sleeves and washers.
Machined in Aurora
How your rings are made
±0.002"–
±0.005"
On critical dimensions, depending on the plastic.
- Rings and sleeves CNC turned so the outside and bore stay concentric. Bolt patterns, flats and splits milled.
- Machined from the exact grade you specify, with specs kept for reorders.
Evaluating a supplier? See the shop and how we check the work.
Buyer questions
Insulating ring FAQs
Something else? Call (630) 904-2525.
We machine the plastic pieces to your specification: the gasket, sleeves, washers or rings. Tell us which pieces you need. Metal retainers and the overall kit design stay with your kit supplier.
Ratings come from the exact grade, thickness, test method and your specification. We machine the ring from the grade you name, and can tell you what documentation comes with that material.
It’s one published way to protect a bearing, but it can push the current to another component. It belongs in a wider plan from your engineering team.
We hold ±0.002" to ±0.005" on critical dimensions, depending on the plastic. We review your drawing and confirm the critical dimensions, such as bore and thickness, with your quote.
Not an insulating ring?
Find the right part
We machine almost any plastic part. If yours isn’t listed, describe it in a quote request.
Standard quote
Ready to send your ring details?
Experienced help from your first quote to the finished part.