Pfaff 345 sub base needed

[barclay]

345 h3 cast iron sub base, the part that holds the head to the table.  The one I have is from a singer I think and is too tall and not the right width for the pfaff.  The singer is about 6" tall and I would like the lowest base possible, maybe 2".  Where can I get such a cast part.  If all else fails I will cut this one down. But I will search first.  thanks

[barclay]

the black base is the wrong size and not a Pfaff.  Machine is too tall and need a lower base.  Any ideas?

[Handstitched]

All the pics I've seen of the 345's don't have that extra black  bit with the clip on . Can that be removed? Or get another bench with adjustable height ? It would be  quite a tall order to modify the Singer base. 

HS

Edited May 7, 2023 by Handstitched

[kgg]

 

@barclay

I would:

i) call around to the repair shops and try sourcing one as they may have a donor machine.

ii) get a new one from a PFAFF dealer if they are still available. The parts you need can be found on page 4 of "Housing Sections" of the listed in the following topic as a downloadable manual "parts5ao8mf6d.pdf". The base part number is: 91-014 200-75/995

iii) have a welding shop fabricate a support frame probably using 3" angle iron

iv) as you suggested cut down the one you have.

 

kgg

Edited May 7, 2023 by kgg

[barclay]

thanks for the wisdom.

[barclay]

I decided just to cut and weld.  Its ready to weld tomorrow.  I can weld it from the inside to hide the weld , paint it and its done. I took out almost 4".  Hinge and latch holes are still intact.  No drilling no tapping.  Now waiting for a servo to show up.  At that point I will need to reduce the speed etc.  onward.

[kgg]

5 hours ago, barclay said:

I decided just to cut and weld.  

That is what I would have done. A few cutting disc later and the basic job is done. Are you planning on modifying the existing Singer treadle table to accept a servo motor or building a new table? With the servo motor I would install it first before putting a speed reducer on as you may find it not necessary, depending on what you want to sew.

kgg

[barclay]

one disk and a jig and the 2 cuts went better than expected.  I will keep the singer table as it is cool.   The servo goes down to 300rpm and with a small pully and a 5.5" handwheel pulley I will get about 100 spm i think. could be slower for the thick leather so reduction may be in order..

[barclay]

base done, much more acceptable height.  On to the next issue.. a bigger handwheel pulley, to slow things down a bit.  Back to the lathe for that.

[kgg]

5 hours ago, barclay said:

base done, much more acceptable height.  On to the next issue.. a bigger handwheel pulley, to slow things down a bit.

Nicely done. As a note if you want the base color to be a better match, try your auto supply store for a tin of spray paint. I used one for a Toyota to match the base color of a PFAFF flatbed.

A good pulley size calculator to checkout before you hit the lathe is: https://www.blocklayer.com/pulley-belt

Example A:

Small pulley at servo motor with a 5.5" hand-wheel pulley with a motor speed of 300 rpm will give you a hand-wheel rpm of:

i) 2" pulley at servo motor: 109 rpm

ii) 3" pulley at servo motor: 163 rpm

to get those speeds down to say 40 rpm at the hand-wheel the new hand-wheel pulley would have to be:

i) 2" pulley at servo motor: 15 inches in diameter

ii) 3" pulley at servo motor: 22.5 inches in diameter

Personally I would suggest putting a speed reducer in, double bearing shaft or canter lever style, and leaving the existing 5.5 inch hand-wheel pulley for a couple of reasons. Leaves the machine in original condition, helps reduce startup jerk and provides a more uniformed torque range.

Example B:

Small pulley at servo motor with a 5.5" hand-wheel pulley with a motor speed of 300 rpm and installing a reducer pulley (6 inch /2 inch) will give you a hand-wheel rpm of:

i) 2" pulley at servo motor  36 rpm

ii) 3" pulley at servo motor: 55 rpm

kgg