Calculating the correct stud length for your MTH series fastener is essential to ensure a secure and reliable assembly. Follow this step-by-step guide to determine the right stud length for your application.
Step 1: Choose Your Receptacle
The type of receptacle you select will dictate the calculation formula. Common receptacle types include A, B, C, D, and E, each with specific requirements.
Step 2: Measure Your Panel and Frame Thickness
- Panel Thickness (P): Measure the thickness of the panel where the fastener will be installed.
- Frame Thickness (F): Measure the thickness of the supporting frame.
Step 3: Account for the Retaining Washer
Choose the retaining washer you plan to use. Options include standard, flush, or specific types like MTHWSS, MTHWFS, or MTHWFTP.
Step 4: Apply the Correct Formula
Use the formula based on your chosen receptacle type:
- Type A + E + F + G:
T = P+F
Minimum Total Thickness (T): No restrictions.
- Type B:
T = P+F
Minimum Frame Thickness (F): 0.75 mm.
- Type C:
T = P+F
Minimum Total Thickness (T): 9.9 mm.
- Type D:
T = P+X
X = 0.5 mm (minimum)
Step 5: Adjust for Gaskets (Optional)
If your assembly requires sealing, use gaskets like MTHGIR or MTHGOR. These gaskets add 0.75 mm to the total thickness, which must be factored into the formula.
Examples of Stud Length Calculations
Here are five examples to help you understand the process:
Example 1:
- Panel Thickness (P): 3.00 mm
- Frame Thickness (F): 1.50 mm
- Receptacle Type: A (MTHR25BZ, bronze with zinc plating)
- Stud Type: Wing-headed, steel zinc-plated
- Retaining Washer: MTHWSS
Formula:
T=P+F=3.00+1.50=4.50
Using the Type A Stud Length Table, T=4.50 corresponds to stud length 5, suitable for total thicknesses between 3.80 mm and 4.60 mm.
Part Numbers:
- Stud: MTHTLW-5Z
- Retaining Washer: MTHWSS
- Receptacle: MTHR25BZ
Example 2:
- Panel Thickness (P): 7.20 mm
- Frame Thickness (F): 4.50 mm
- Receptacle Type: B (MTHRPM2HA, aluminum)
- Stud Type: Folding ring handle, stainless steel
- Retaining Washer: MTHWFS
Formula:
T=P+F=7.20+4.50=11.70
Using the Type B Stud Length Table, T=11.70 corresponds to stud length 16, suitable for total thicknesses between 11.40 mm and 12.20 mm.
Part Numbers:
- Stud: MTHTLFR-16S
- Retaining Washer: MTHWFS
- Receptacle: MTHRPM2HA
Example 3:
- Panel Thickness (P): 3.20 mm
- Frame Thickness (F): 10.50 mm
- Receptacle Type: C (MTHRF25S, stainless steel)
- Stud Type: Cross-headed, stainless steel
- Retaining Washer: MTHWFS
Formula:
T=P+F=3.20+10.50=13.70
Using the Type C Stud Length Table, T=13.70 corresponds to stud length 6, suitable for total thicknesses between 13.70 mm and 14.50 mm.
Note: When TTT is on the limit between two stud lengths, choose the longer length.
Part Numbers:
- Stud: MTHTLC-6S
- Retaining Washer: MTHWFS
- Receptacle: MTHRF25S
Example 4:
- Panel Thickness (P): 8.15 mm
- Frame Thickness (F): 8.00 mm
- Receptacle Type: D (MTHRTZZ, zinc die-casted)
- Stud Type: Slotted-headed, steel zinc-plated
- Retaining Washer: MTHWFS
Formula:
T=P+X=8.15+0.50=8.65
Using the Type D Stud Length Table, T=8.65 corresponds to stud length 11, suitable for total thicknesses between 8.40 mm and 9.15 mm.
Part Numbers:
- Stud: MTHTLS-11Z
- Retaining Washer: MTHWFS
- Receptacle: MTHRTZZ
Example 5:
- Panel Thickness (P): 3.00 mm
- Frame Thickness (F): 1.50 mm
- Receptacle Type: E (MTHRA24S, stainless steel adjustable)
- Stud Type: Flush cross-headed, stainless steel
- Retaining Washer: MTHWFTP
Formula:
T=P+F=3.00+1.50=4.50
Using the Type E Stud Length Table, T=4.50 corresponds to stud length 3, suitable for total thicknesses between 4.32 mm and 9.65 mm.
Part Numbers:
- Stud: MTHFTLC-3S
- Retaining Washer: MTHWFTP
- Receptacle: MTHRA24S
Final Tips
- Always double-check your calculations using the Turnlock catalog.
- If your total thickness falls between two stud lengths, choose the longer length for a better fit.
- For sealed assemblies, include the gasket thickness in your formula.
By following these steps, you can confidently select the correct stud length for your MTH series fastener.