[bigspike]

I have the Keling KL-34-180-90 & KL23-120-36 & KL23H276-28-4B motors and they have small holes in the end that are threaded and will align with the encoder bases I have, but I cannot determine the thread size.

Sighting down the hole and measuring with calipers, they measure around .085" (2.15mm)

Also do you sell or know where I can get end caps to protect the encoders on NEMA 34, 23 servo motors as well as NEMA 23 stepper motors, I have designed some to mill from aluminum, but if they are already available at a reasonable price, I may just buy them.

[RICHARD ZASTROW]

The Heidenhain encoders we use have 4mm mounting screws.

Dick Z

[bigspike]

No way will a 4mm screw fit in the holes I need to use ... all of the motors have the same size holes near the spindle for mounting the encoders. The nema 34 servo motors do have some 4mm holes spaced farther out that I plan to use for mounting an encoder enclosure.

The digikey encoders that I have have 2 mounting plates. One with ears for screw mounting and the other without. Both have holes that match up with the small holes in the motors. None of the mounting plate holes come close to the 4mm wider spaced holes.

I did find a reference on one of Kelings spec. pdf's that stated 2mm hole size but did not specify the pitch or depth.

[Al_The_Man]

.086 is #2 screw size and often used for Renco and other encoders for mounting.
Renco is now owned by Heidenhain.
Al.

[bigspike]

I would think with everything else on the motor being metric... that even these small screw holes would also be metric.

I tried another tactic to measure them.
A No 45 drill bit fits snugly down inside the screw threads and measures 0.080" on my dial caliper.
A No. 44 drill bit will not fit and measures 0.084".
2mm is .0787"
2.5mm is 0.0984"
None of my assorted loose computer screws fit into the holes.

Attached is a picture of the holes in question

[ecortech]

According to the drawings on Keling website the servo's are #4-40unc x 5mm deep
The stepper is M2.5

[Al_The_Man]

None of my assorted loose computer screws fit into the holes.
Attached is a picture of the holes in question

I found that #2-56 is fairly rarely used in practice .
Pololu - Machine Screw: #2-56, 7/16" Length, Phillips (25-pack)
I did find a #2 tap set however.
Al.