1. Motors- SQ100D is 900W induction type motor and SQ100F is 1500W induction type.
2. RPM- SQ100D is two speed 24/10rmp, SQ100F is three speed 36/20/11rpm. Different efficiency.
3. Threads types available- SQ100D can make BSPT, NPT, Metric threads, SQ100F can make BSPT, NPT, Metric, BSPP, NPSM.
4. Threading dies brands and types- SQ100D uses F4 type and REX similar type dies, SQ100F uses RIDGID compatible types of dies. They are different brands. SQ100D is for Asian market and SQ100F is for North and South American market. It depends on your using hobbies.
5. Threads Precision- 1/2"-2" dies are full teeth dies, the precision is higher than 2 1/2"-4" profiling types. Because full teeth dies can finish threading in one turining while the profilling ones cannot. See the pictures.
6. Appearances- SQ100D is using pressure casting while SQ100F using precision foundary casting
One is beautiful and another is strong.
7. Noise- SQ100D is about dB80-82, SQ100F is about dB78-81.
Hope you will find out the suitable ones as per your requests!