Misumi USA Engineering Blog

Need more information about locating pins?

Check out the below link to the MISUMI VOICE Vol5. This issue features a technical article covering the various usages for locating pins:

http://www.misumiusa.com/globalvoice/volume5/article1a.aspx

The Linear Ball type stages use an integrated Gothic Arc design which provides high rigidity and precision, but uses fewer components and thus decreases the probability of alignment errors. It requires less space, and is more cost effective. It is made of stainless steel, which does makes it slightly heavier and gives it a metallic look.

The 2008 Metric Catalog features10 pages of NEW Linear Ball type products starting on page 935. 

Click here to visit page 935 in the online catalog. 

It is understood that all stainless steel is not created equal. There is a definite difference between the various stainless steels available today. This blog will discuss the differences as they pertain to mechanical components used in factory automation.

AUSTENITIC GRADES- (300 series) are non magnetic in the annealed condition, although some may become magnetic after cold working. They can be hardened only by cold working , and not by heat treatment. Combine outstanding corrosion resistance with good mechanical properties over a wide temperature range. The most common grades are: 303, 304, 316, 321 etc…Misumi offers 303, 304 and 316 grade.

FERRITIC GRADES- are always magnetic and contain chromium but no nickel. They can be hardened to some extent by cold working, but not by heat treatment, and they combine corrosion and heat resistance with moderate mechanical properties and decorative appeal. The ferritic grades generally are restricted to a narrower range of corrosive conditions than austenitic grades. The most common grades: 405, 408, 430 (Offered by Misumi) etc… Misumi offers 430 grade.

MARTENSITIC GRADES- are magnetic and can be hardened by quenching and tempering. They contain chromium, and with two exceptions, no nickel. Some are modified to improve machinability and other have a small addition of nickel to improve the mechanical properties or their response to heat treatment. Some of them have greatly increased carbon content and are hardenable to the highest levels of all stainless steels. These are excellent for service in mild environments such as the atmosphere, freshwater, steam, and weak acids, but are not resistant to severely corrosive solutions. The most common grades: 410, 420, 440C (Offered by Misumi). Misumi offers 420 and 440C grade.

M2.6 thread size is not a catalog mistake.  This is the correct size when listed in the catalog.  If you are having trouble locating hardware, we also sell hexagonal socket head cap screws with a M2.6 thread (Misumi part numbers: CB2.6-5, CB2.6-8, CB2.6-10, CB2.6-12, and CB2.6-15, where the last number in the part number refers to the length).

Our catalog often shows surface roughness information at the upper right hand corner of the drawing. This information will show a roughness value, and one or multiple values in parentheses. Please, see the example from page 159 from FA 2008 metric catalog. "Photo 1" The value before the parentheses means: unless otherwise specified, all surfaces are 6.3 μm and all values in parentheses represent other surface roughness specified on the drawing. 

Surface finish (surface roughness) specifications is a large topic. In fact discussing this topic in length would take at least a few pages. For this blog entry I would simply like to focus on the machined components in the Misumi catalog and point out that these components have surface finish specification (symbol and value) specified in the catalog. Please note that the surface roughness average value (Ra) in the Misumi metric catalog is measured in μm (micrometer-10-6mm) while in Misumi inch catalog it is measured in μin (microinch-10-6in).

See below as the preferred values for Roughness Average (Ra) are given in following table¹.

Metric threads have a different callout then US (inch) threads. Metric threads specify the pitch while US threads specify number of threads per inch.

Example:
Metric
M6 x 1 ( 6- nominal thread diameter in mm, 1mm-distance between threads in mm)

Inch
¼-20 (1/4-nominal thread diameter in inch, 20-number of threads per inch)

Pitch from metric fasteners can be coarse, fine and extra fine. The pitch callout on coarse thread is often omitted. For example, “M6” thread by default stands for coarse thread M6 x 1. Thread call out that includes the pitch “M6x0.75” specifies non-coarse thread (in this case fine thread). Also all threads are right-hand threads unless otherwise specified.

Majority of standards (JIS, ISO, DIN) follow this convention.

For more information about Metric Coarse Threads please see pages 2568/2569 in the 2008 Misumi Metric catalog. Also, see the following links.

Table for Metric Coarse Screw Threads
Table for Metric Fine Screw Threads

When dealing with the Case Hardness of Precision Linear Shafts very often Misumi engineers are asked if our linear shafts are case hardened or through hardened. If you look at the part specification table for Misumi precision linear shafts you will notice that a majority of our shafts are induction hardened. Induction hardening is just one of the ways to achieve case (surface) hardness. Through the induction hardening process the top layer of the shaft is hardened which increases the strength and wear resistance. At the same time the shaft core remains unaffected and material ductility and other physical properties are preserved. Hardness varies with the type of material while effective hardness depth depends on shaft diameter. Values for effective hardness depth can be found in Misumi catalog. See the following links.

Effective hardness depth for metric shafts
Effective hardness depth for inch shafts

We often receive inquiries regarding unspecified tolerances of particular component dimensions in the catalog.  We always do our best to inform the customer of all tolerances right on the product page. You will notice that the Misumi catalog covers most product dimensions as well as tolerances. There is, however a rule that is not clearly explained. Unless otherwise specified on the product page, the tolerance for most of Misumi Metric machined components (i.e. washers, collars, bearing housings, locating pins etc.) is located in the technical data section of the catalog. Please follow the medium precision tolerance in "Regular Machining Dimension Tolerance" tables.

It is always best to check with Misumi Engineering Team (engineering@misumiusa.com) and verify the tolerance.

Remember that some component tolerances (like bearings, bolts etc.) are also located in the back section of the catalog and have their own, special section.

We strongly suggest sending inquiries to engineering on all other unspecified tolerances for parts that are not machined (metal casts, extruded or molded parts etc.)

Welcome to the Engineers Blog, the blog for engineers, written by engineers. Common topics for this blog will include geometric tolerances and fits, materials, surface treatments and hardness, various calculations, product selection criteria plus frequently asked questions and other topics as well. Our head of engineering, Chris Blaszczyk, will be contributing to this blog regularly and is sure to add to this list. Chris is often busy creating materials and presenting at our Configuration Tech Seminars which have proven to be a valuable resource for engineers.

This blog is dedicated to mechanical components used in automation and the machine design and build process. It is meant to be a forum of knowledge that will help the engineer quickly and easily find resourceful information for various topics. In addition we will use this blog to link to various helpful technical resources across the web. To get things started feel free to check out this section of technical reference guides by visiting: https://www.misumiusa.com/PDFViewer.aspx?Metric=true2008&Page=2526.

Lastly, feel free to comment on any of our postings to this blog. We welcome and encourage all comments and feedback. Remember this blog is here for you to use as a resource so please enjoy.