Advice on crimping tool selection

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Senior Member


New User
Fairhope, AL, US
What's the difference between O and BG die? Pros and cons of either?

Does the D3 groove use/require a specific type of die?
What style of die works best for my application? (See post #1 for my info)
For all of the questions above about which tool and die to use, start with the wire size and type, then the connectors you will be using. The connector determines the tool, not other direction. Some statements made above are not exactly correct. Today, there is no such thing as a UL Listed tool. If your work is going to be under the NEC and the connections need to be UL listed you must use the tools/dies recommended by the connector manufacturer to comply with the UL listing or the CSA certification. The UL Classified tools on the market are extremely limited in what they can crimp with UL coverage. The only applications covered are on that tool case label and only those conductor types. For example no flex (welding, locomotive, flex motor leads) will be UL Listed and therefore not covered in the NEC. Also only tubular connectors are currently covered and no grounding/bonding applications are covered by the Classified tools. These details as stated above in the Motor Shop may not be called out by an AHJ, but in bad times, you will own that violation. Neither the UL Classified tool supplier or the connector company are responsible for installations that do not follow their directions.

The D3 Groove serves two purposes. It is a very common die profile in the Utility Service Entrance market. Connector families that use a common die for several connector/conductor combinations. Just as the O and BG are. Typically the connector OD is the same while the ID varies for conductor sizes. The Burndy MD6 mentioned above can be supplied with other fixed dies such as O, or BG in the nose and a snub nose with just the D3 for tight clearances. The D3 Groove is also the seat for a series of insert dies as a family, W series and X series. Some of these install UL listed connectors up to 500 copper lugs and splices. You are not using the D3 groove as the crimping profile for that, you are using a die that is inserted into the D3 Groove for that range. Pins hold the W and X dies. 1. Wire size and type; 2. Connector; 3. then the die choice which will determine the number of crimps on that connector; 4. then the tool.

Be careful linking tool crimp force (6 ton or 12 ton) directly to wire size range. This subject tool with the D3 groove would be in the 6 ton family and as stated with correct dies can crimp UL Listed connectors up to 500 Kcmil copper. You cannot use that same tool to crimp a UL Listed Copper C crimp for that wire range. It does not even make a good bend to the connector. That would require a 12 ton type tool and a U die. Some wire range claims by generic tools on the market do not clarify this. That can be dangerous.

I have this tool and this die, what connectors can I crimp? This is not a simple answer. It ranges from one connector on one very specific conductor to 100's of connectors and conductor combinations.

tom baker

First Chief Moderator
Staff member
Your crimper purchade may be the only one you purchase.
1. Look at which wholesale house has best selection of lugs, and who is mfg?
2. Have the tool rep come by for a demo.
We had a nice greenlee set, older battery tool, could no longer get batteries, then went with 6 T milwaukee M18. 12T would of done larger C taps, good for grounding. Liked Milwaukee ad we were all on on M12 snd M18 tools.