Menu
Cart 0

FAQ

General

What are the benefits to using a Modular Fixture Plate on a CNC machine?

Modular fixture plate benefits include:

  1. Increasing the workholding, clamping and setup area
  2. Convenience of having hundreds of bored and tapped holes versus a few t-slots
  3. Indexing, shifting, locating and holding large parts
  4. Clamping large parts outside of the machining envelope
  5. Using the SMW Mod Vise low profile, modular work holding system!
  6. Protecting the CNC machine table (often made from soft cast iron)
  7. Quickly aligning, tramming, and clamping vises and other workholding
  8. Using custom, hot-swappable fixture plates tops

Should I buy an aluminum or steel Fixture Plate?

Aluminum benefits: lower price, lighter weight means reduced shipping cost and easier installation, and scratch-resistance hardcoat anodize.  
Steel benefits: longevity, toughness, strength.
The SMW steel fixture plates are made from a heat treated, hardened chrome-alloy steel (4140).  They are strong, tough and durable.  SMW Steel Fixture Plates are well suited for daily, industrial use!
The SMW aluminum fixture plates are made from 7075 aluminum, a high strength aluminum with almost double the yield strength of general purpose 6061. Each tapped hole in the SMW aluminum fixture plates is form tapped which creates a stronger thread by cold forming the grain flow of the material.   

We only offer aluminum fixture plates for the Tormach line (440, 770, 1100).  We do not offer custom aluminum fixture plates due to the batch size require for hardcoat anodizing.

What is the Fixture Plate hole spacing?

Standard SMW fixture plate holes are spaced 1.25" on center

Is each hole bored and threaded?

Yes, each hole is precision bored 0.25" deep for use with a 1/2" dowel pin, the SMW Mod Vise or other 1/2" accessories.   Below the precision 1/2" bore, each hole is tapped 1/2x13.

What Torque Specs should I use on the Fixture Plate?

We recommend 60 ft-lb (81 N-m) for the low-profile SHCS that secure the fixture plate to the T-Nuts.

The appropriate torque when using the fixture plate for workholding depends on a variety of factors, including the thread engagement of the stud or screw into the fixture plate. 

For the 1/2x13 holes in aluminum plates, we recommend up to 45 ft-lb or 61 N-m.  DO NOT exceed 50 ft-lb or 68 N-m.    

For the 1/2x13 holes in steel plates, we recommend up to 50 ft-lb or 68 N-m. Do not exceed 70 ft-lb (94 N-m). 

What is the greasy, sticky stuff on my fixture plate?

We apply a light coat of LPS3 to steel fixture plates prior to packaging and shipping.  This can be easily removed with traditional solvents or cleaners such as WD-40 or acetone.  We recommend leaving steel products lightly coated with a rust inhibitor, particularly for shops located in environments prone to rust (e.g. high humidity, near saltwater, etc). Refer to article on NYCCNC.com for tips on avoiding rust in the machine shop.

Why does my aluminum plate have four set screw in the back?

These are used for fixturing during the anodizing process

 

Do you provide Solid Models?

Yes, click here

 

Will you create a custom plate for my machine?

Email us at   to inquire about custom fixture plates for your CNC machine

How do I setup and install my SMW Fixture Plate?

Click here to watch our instructional video

How do I prevent rust on my fixture plate?

Click here to read our article on machine shop rust prevention

What maintenance do I need to do on my Fixture Plate?

We recommend any workholding device (fixture plate, vice, 4th axis, etc) be periodically removed and cleaned.  This interval depends on personal preference, frequency of use, types of material being cut, coolant and more but generally should be inspected every 3-12 months.  See FAQ item above for tips on preventing rust.

What is the leadtime on Fixture Plates? Do you keep them in stock?

Standard leadtime is two weeks from order.  We keep stock on hand for standard fixture plate sizes but machine the plates on a just-in-time basis.  Certain plates for popular machines and configurations are kept in stock.  Please contact us with questions about leadtime or to inquire about rush orders.


Mod Vise

How do I use my SMW Modular Vise System?

Click here for our instructional video on how to use your Mod Vise

What is the difference between the Pitbull and Tiny Vise version?

Tiny Vise: each Tiny Vise clamp offers two clamping edges:  one serrated edge for better gripping and one smooth edge for lighter, but non-marring clamping.  
Pitbull:  The Pitbull clamps use the Mitee-Bite Pitbull clamp which offers higher clamping forces than the Tiny Vise.  We generally prefer using the Pitbull for this reason.

Will Mod Vises work with non-SMW fixture plates?

Mod Vises require the unique combination of having each fixture plate hole both bored for 1/2" precision pins and tapped 1/2x13".   Generally speaking, the Mod Vise will not work on other brands of fixture plates.

 

Tolerances

What is the parallelism tolerance of an SMW Fixture Plate?

SMW Fixture Plates are held to parallelism of +/- 0.0005" per 18" .

What tolerance is the flatness of a SMW Fixture Plate held to?

We do not qualify plates in an unconstrained state.  However, we do evaluate and process the raw material in a specific way so that when the fixture plate is secured to the machine table, it's "flatness" will be the result of the thickness tolerance plus any deviation, level, or tram error in the machine table.


How precise is the bored hole diameter on a SMW Fixture Plate?

The 1/2" precision bores on the SMW Steel Fixture plates are machined to 0.5005" +/- 0.0002".  We have found this to be the ideal tolerance when using a mix of dowel pins, gauge pins and accessories like the SMW Mod Vise.  Keep in mind, for a dowel pin to have a "slip" fit (e.g. not require hand tools, vice grips, etc to remove), there must be some gap or "slop" in the fit between the pin and the hole.  
The 1/2" precision bores on the SMW aluminum fixture plates are held to approximately 0.5005" +/-0.0004".  The additional tolerance range is due to the variability of the hardcoat anodizing process.

What if a dowel pin has a loose fit?

Dowel pins can be purchased with varying degrees of tolerance and fit, but traditional "off the shelf" dowel pins (e.g. this 1/2" dowel pin from McMaster Carr) have dimensional tolerance of 1/2" +0.0001 to +0.0003.  A pin cannot fit in a hole of the same size; the hole must be larger.  Our hole tolerance, as described above, allows for this fit.   However, adding a relatively small amount to a bore diameter - even 0.0001 (a.k.a. "one tenth" of an inch) results in a notable difference in the feel and fit of how a pin fits into a hole.  We use a combination of metrology tools, including bore gages and deltronics gage pins, to ensure bores meet our tolerances.