Installation of a DIY Feed Rate Scale on a DF520

Questioning why EFM has been manufacturing boilers for this long and have never incorporated a simple feed indicator scale of some design similar to their current air scale I decided to add my own feed scale for my DF520. I took a piece of 1¼” wide x 4¼” long thin gauge metal and bent a ¾” 90 degree angle at one end. I drilled a hole in the angle end for mounting. I drilled the hole a bit off center so I could get the scale as close to the thumbscrew and steel guide as possible without interfering with their movement. I removed a bolt from the bracket bearing and bushing assembly that is closest to the thumbscrew and placed the bolt thru my scale and retightened back into its original location.

I followed the EFM instructions to adjust the feed rate and with a Sharpie marked my scale with settings ranging from 3 to 8 teeth. I have room to mark additional but this winter (my first year with an EFM) the max I adjusted to was 7. You can choose to use the leading end of the steel guide as your guide line (pointer) or there is a rivet head (small bump of steel) on the steel guide that you can use as your reference point. Realizing of course that if you mark with one you can’t then adjust using the other as you will be two teeth off.

Feed adjustments may not be needed that often but once the scale is set up all future adjustments can be made instantly and accurately while the boiler is in operation. Others can easily adjust for you should you not be available when adjustments are needed. Line up your reference point to the mark on the scale and you’re done! No more finger on the pawl counting teeth or powering down to adjust manually. Attached is a picture of the scale viewed from above as well as a side view to observe the mounting bolt if anyone else is interested in incorporating a similar or enhanced design.

Good idea I was thinking the same thing. I was given a brother labeler recently and was going to use high endurance hello tape , print out a calibrated scale clean up the metal with acetone and see if it sticks. All the same idea