Are your part’s tolerances tighter than necessary? If so, chances are you’ll overpay for that part when you could get it for less money without compromising on performance. 

Visualize a bracket designed to hold a light. Our precision machine shop could quickly and easily mill that bracket with standard +/- 0.005” tolerances for, say, $75. But add precision tolerances to every feature on the part, and you could see the cost skyrocket to nearly $900! 

When you need tight tolerances, our experts are well-equipped to meet your specifications. But why pay for precision you don’t need? Instead, take these engineering design tips to heart and avoid the pricey over-tolerancing mistakes we often see.

Tolerancing Mistakes That Cost Customers Time and Money

You’ll see immediate savings when you avoid two common design missteps.

1. Requesting precision tolerances on the entire part

Most drawings include a tolerance block where the engineer designates default tolerances for features that aren’t individually assigned specific tolerances throughout the drawing. For anyone unfamiliar, a tolerance block typically looks something like this: 

The problem arises when an engineer writes every part dimension as a four-place decimal, which indicates to the machinist that they must default to precision tolerances across the part. 

Shop Tip: Think critically about the necessary tolerances for each feature. 

2. Over-tolerancing the mating components in an assembly 

When machining parts for assembly, we often discover that the parts have tight tolerance specifications even though they would fit together equally well with looser tolerances. We understand an engineer’s desire to make every part “perfect” with precision tolerances. But when it comes to assemblies, what matters most is achieving a perfect fit, and that doesn’t always necessitate the tightest of tolerances.

Shop Tip: Talk to our team about the fit of your mating parts, and we’ll help you identify the ideal tolerances for a great fit. Conversations about Design for Assembly (DFA) are a big advantage of sourcing all assembly components from the same shop.

Cost-Sensitive? Let’s Have a Conversation

Every customer wants the best possible price for their manufactured parts, but we recognize that some projects are more cost-limited than others. If you’re working on a particularly cost-driven project, consider reaching out to your preferred precision machine shop and saying to them, “This is the part I need. What are the most cost-effective solutions?”

We’re committed to helping you get the best parts at the best price, and the most common opportunities for cost reduction involve loosening tolerances.

Ready to request a quote? Ask our precision machine shop to flag your RFQ for cost-reduction solutions, and we’ll see how we can help!