Myford ML7 - Carriage Lock


I fitted a collar, with a handle, over the the head of the carriage locking bolt.

Continually locking and unlocking the carriage bolt using a spanner is a nuisance.

This modification does away with the 1/4 Whitworth spanner, which is one less tool to have laying around the lathe.

This modification speeds up the process of locking and unlocking the carriage.

The existing bolt is not altered in any way.

The new locking lever assembly has a very low profile, so it does not interfere with the locking lever on the tailstock.


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↓ This is the collar.

The collar fits over the head of the existing bolt.
The collar is the same thickness as the existing locking bolt and washer.

One face of the collar has a recess, which can be seen in this picture. The recess accomodates the washer that is under the existing bolt head, and allows the collars to sit nicely on the machined surface on the carriage.

The collar fits very closely around the apexes on the bolt head.

The collar dimensions are:-
OD = 25.4mm
ID = 15.3mm
Thickness = 7.68mm

The holes were positioned and drilled using a rotary table on the milling table.
The rotary table settings were as follows:-

2.5mm diameter hole - tapped M3 - at 0 degrees.
2.5mm diameter hole - tapped M3 - at 180 degrees.
4.2mm diameter hole - tapped M5 - at 240 degrees.


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↓ The other parts of the assembly are two small socket head screws, and a handle/lever.

The socket head screws are M3.
The handle is 5mm in diameter.
The handle is 52mm long (including the threaded portion).
One end of the handle is threaded M5.
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↓ The two M3 socket head set screws are screwed into the collar, and when tightened, they bear down on the flats of the bolt head. This firmly secures the collar to the bolt head.

This picture shows the top face of the collar; the face with the recess that fits over the washer is on the underside.

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↓ Here is the Ml7 carriage lock bolt with its washer underneath.
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↓ The existing carriagle lock bolt is not central on the machined boss.
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↓ Here is the locking assembly in position on the bolt head.
You can see the m3 screws bearing on the flat edges of the bolt head, at 2 o'clock and 8 o'clock.

The 6 apexes of the bolt head are touching the inside surface of the collar.

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↓ The locking assembly in the unlocked position.
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↓ The locking assembly in the locked position.
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