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Q-Mark Probe Styli: Orders Placed by Noon PT Ship Out Same-Day* | Ultra-Fast Service | Always Guaranteed | Proudly USA Made
Q-Mark Probe Styli: Orders Placed by Noon PT Ship Out Same-Day* | Ultra-Fast Service | Always Guaranteed | Proudly USA Made

Frequently Asked Questions

Same-Day Shipping

Q: When will my order ship?

A: Online orders received by 12:00 noon Pacific Time, Monday through Friday, will ship the same day.  Orders received after 12:00 noon PT may be delayed one business day.  All of our online products are in stock and ready to ship.  Please note: Unexpected demand may cause delays.  Should this occur, we'll contact you for your instructions.

In Stock and Ready to Ship

Q: Is it in stock? When will it ship?

A: All of our online products are in stock and ready to ship. We average an order fulfillment time of 2.5 hours during regular business hours. On average, your product is boxed and ready to ship or pick up within a few hours.  Please note: Unexpected demand may cause delays.  Should this occur, we'll contact you for your instructions.

I Didn’t Receive My Instant Quote?

Q: Why didn’t I receive my Instant Quote?

A: Make sure you entered your correct email address.  If you entered the correct email address, the quote might be in your spam folder. The quote email is sent from “Q-Mark <> via“ and the subject line is, “Quote From Q-Mark Manufacturing Inc." You can try searching your spam folder for this subject line. If the email is in your spam folder, please mark the email as “not spam” to make sure you receive future quote emails.  If you still can’t find your quote, please contact us for assistance.  Our styli experts are ready to help.

XXT Products

Q: What's the difference between M3 and XXT products?

A: M3 products use 4.0 mm diameter stainless steel bases and fittings with carbide or ceramic shafts.  XXT products use 5.0 mm diameter titanium bases and fittings with carbide or graphite shafts.  XXT products weigh less than similar M3 products. 


Q: How do I tell the difference between TL1, TL2 / TL4 and TL3 XXT Adapter Plates?

A: The carbide spheres on the top of the plate are in different positions.  See illustrations, below:

TL1 Plate

This is a TL1 adapter plate.  Note the side-by-side position of the two carbide spheres at the 12 o'clock position. This plate fits TL1 probe heads. 

TL1 XXT Adapter Plate From Q-Mark

TL2/TL4 Plate
This is a TL2/TL4 adapter plate.  Note the single carbide sphere at the 12 o'clock position. This plate fits TL2/TL4 probe heads. 

TL2/TL4 XXT Adapter Plate From Q-Mark

TL3 Plate
This is a TL3 adapter plate.  Note the space between the two carbide spheres at the 12 o'clock position.  This plate fits TL3 probe heads. 

TL3 XXT Adapter Plate From Q-Mark

Technical Information

Q: What is the best sphere material choice for my application?

A: Ruby spheres have long been the industry standard, thanks to their high hardness, excellent spherical form, low coefficient of friction, relative low cost, and good abrasion resistance.  We recommend using ruby spheres for most measurement tasks.

That said, there are certain applications where we recommend spheres made from other materials.

Silicon nitride spheres exhibit superior performance when measuring untreated aluminum and brass.  When a ruby sphere repeatedly touches a soft material, bits of the material will adhere to its surface.  Silicon nitride resists material buildup.  Silicon nitride is also a better choice for abrasive surfaces, like high temperature alloys and EDM cuts. 

Zirconia spheres are best on cast iron.  Cast iron can quickly wear out a ruby sphere.

Diamond spheres are the best choice for any material.  Diamond spheres never wear.  Soft materials won’t adhere to a diamond sphere.  Bonus: diamond spheres won’t scratch.  Not even a mirror finish.


Q: How do I clean an adapter plate?
A: Clean the contact points using a lint-free cloth moistened with a small amount of 70% isopropyl alcohol.

Q: How do I know which thread size to order?
A: Using metric calipers, measure the thread diameter on an existing stylus.  Round the result to the nearest whole number.  That’s your thread size.  2 mm equals M2, 3 mm equals M3, and so on.


Q: What is the thread size on Q-Mark's calibration spheres?

A: All calibration spheres have M6 threads.


Q: What should my Dynamic probing force be when qualifying very small styli? 

A: For qualification of miniature styli sizes 0.5mm and smaller remember to also lower your Dynamic probing force (in %) to 20% or less. This along with lowering your Probing force (in mN) will keep you from breaking your styli tips during qualifying.


Q: How do I qualify very small styli? 

A: There are three steps. 

1. First, verify that your CMM’s probe system has the capability to use styli with spheres that are 0.5 mm or less in diameter. Certain probe systems aren’t compatible with very small styli.

2. Always use a small calibration sphere. We suggest 8.0 mm diameter.

3. Adjust the probe force to the minimum level. Lower the dynamic probing force to 20% or less, if possible.

Follow these three steps and you’ll achieve successful and consistent qualification of delicate styli. If you have any questions, please feel free contact our experts at We’re here to help.


Q: How do I qualify a disk probe?

A: Take at least 12 probings all over the disk.  For example, take 4 points around the equator.  Then move half the distance to one edge, and take 4 more all around.  Move to the opposite side and take 4 more all around. Compute the result.  If the standard deviation is too high, start over, taking more points.


Q: When should I use a cylinder stylus?

A: Cylinder styli are best suited for measuring edge features, like the edges of stampings, sheet metal, or thin lands between grooves.  A sphere stylus is always a better choice than a cylinder stylus for everyday measuring tasks.


Q: How do I qualify a cylinder stylus?

A: To calibrate your cylinder stylus you must reduce the calibration sphere coverage angle so that the spherical end of the cylinder stylus is always above the equator of the calibration sphere.  We recommend a coverage of 150 degrees.  Now proceed with the calibration routine.  Please note that the form of the spherical end on a cylinder stylus will never be as precise as a spherical (ball) stylus.  Expect a higher standard deviation value when qualifying a cylinder stylus as compared to a spherical stylus.

After calibration, it is important to measure a known artifact, like a ring gage, to ensure that the result is within acceptable limits.  Sometimes it's necessary to adjust the calibration results to get the correct measurement from the artifact. Only when you are satisfied with the results from the artifact should you proceed with inspection.


Q: How do I open packaged styli?

A: Packaged styli can be very small and fragile. Opening the package incorrectly can damage the contents. Watch the video below to learn how to - and how not to - open our packaged styli. The correct way to open a packaged or mini styli is to open the package carefully by holding the red holder in one hand and carefully pulling the styli directly out of its clear case in a parallel motion like taking a sword out of its sheath or a lipstick out of the case. This prevents the delicate part from breaking.

For further assistance, please contact our styli experts


Returns Are Easy

Q: How do I return merchandise for exchange or refund?

A: For online orders:

  • To return items ordered online, please call us at 1-949-457-1913 or email  A customer service representative will email a return label to you.  Please package the items carefully and place the return label on the outside of the container.  When the items are received by Q-Mark, you’ll receive a full refund to the original form of payment.  If the returned item is covered by our No Hassle Warranty, a new one will be shipped to you at no charge.  Non-warranty returns will be refunded to the original form of payment.  Please note that we cannot exchange items that were purchased online.  Instead, please place a new online order for the items you want, and return the unwanted items to us for a full refund.


For orders placed by email, phone or fax:

  • To return items, call us at 1-949-457-1913 or email  A customer service representative will email you an RMA number and a product return form. Please carefully package the items and ship, along with the corrected form, to:


                                ATTENTION – RETURNS

                                Q-MARK MANUFACTURING INC.

                                30051 COMERCIO

                                RANCHO SANTA MARGARITA CA  92688-2106


Once received and inspected, a refund or account credit will be issued to the original form of payment.  If the returned item is covered by our No Hassle Warranty, a new one will be shipped to you at no charge.  



Still Have A Question? Contact Us

Our styli experts are available to answer any of your questions
7:30am - 4:00pm PST,  Monday through Friday.

Call us at 1-949-457-1913 or send an email to