Filed under: How To Sharpen. Tagged as: electric hedge trimmers, gas powered hedge trimmers, gas trimmers, sharpen hedge trimmers.
Sharpening of electric and gas powered hedge trimmers gets a little more involved as there are many different styles and shaped cutting teeth but I will try to explain it as best I can.
Electic Hedge Trimmers
Starting with the electric hedge trimmer. First check for any bent teeth (anchor fence does a nasty job on trimmers) if any hammer or use vice grips to straighten. remove handle and hand guard if removable (some are modeled as part of the housing). If the top and bottom rails are bolted together (some are riveted) I would remove the 5 or 6 nuts and bolts. Remove top rail bar cover (thin metal strip). Between the rails you will usually find spacers (be careful not to loose these) which the bolts need to pass through upon reassemble (prevents over tightening).
You can now spread the rails some what to clean between them (scrap, wire brush, or use a wire wheel). The lower rail needs to be ground on your bench grinder (usually straight across) following the shape of teeth. This is why I like the 8″ x 3/8″ wheel on a 6″ grinder for more clearance. Better yet is belt driven mandrel set up mounted to a board and hanging out from the front of your bench to allow more maneuverability and clearance. The top rail can be sharpened on either the grinder or belt sander if the cutting teeth are straight. Just follow the existing bevel.
After finishing one side using a thin screwdriver reach into the housing and turn the fan blade to advance or retract the top cutter rail to make the teeth on the opposite side accessible for sharpening.
Some Trimmers have cutting teeth that are curved as well as beveled. With these I would lock the entire hedge trimmer in my vise and sharpen these teeth with a dremel using a flex shaft and a small stone. I also use this method on trimmers with molded hand guards to get the last few teeth where the grinder can not reach in.
Before you reassemble coat the blades with petroleum jelly. Reassemble starting near the housing place the spacer to line up with the hole, slide top rail cover into position and work the bolt in, hand tighten nut. Slide top rail cover to either side then lay in your other spacers over bolt holes, slide top rail cover in position and run bolts in holes. On some units the bolts thread in, if this is the case just snug is good. I generally add a drop of loctite to the nuts just to stop them from loosening. Plug in and test, if blades seem to drag you may have a bolt overtightened.
|Electric Hedge Trimmer|
Gas Powered Hedge Trimmers
As I am more familiar with Echo gas trimmers and pole trimmers this is what I will reference to. With gas trimmers it’s always better to remove the blades from the unit. Be careful doing this the first time. First remove bolts holding blade rails together (metric), these bolts are threaded in and have a raised collar so no spacers are needed between blades. Most units need a bolt removed near the handle first. Remove bottom plate, the drive gear, (before removing the drive gear have the small hole in this gear line up to a tooth on the small gear and mark tooth position, this is a timing mark)remove felt gasket where blade enters housing, bottom blade should now come off. look for a thin spacer type washer between blades(usually sticks to one of the blades with the grease.
As above check for bent teeth as these will prevent trimmer from operating properly. Now the blades can be cleaned and sharpened. The teeth on these type units are much larger and thicker than on electric trimmers (also these units get extremely dull from over use between sharpenings) so for this reason I much rather use a grinding wheel for quicker metal removal. As these blades have a heavy bevel you will need to mount your grinder to a board an extend it out beyond the front of your bench for clearance. Lubricate blades with petroleum jelly and reassemble in opposite order being carefull to put things back in the correct order as they were.
A grinder like this will get the job done if the wood to the left is cut away and the unit is mounted overhanging your bench.
This homemade grinder behind me
is my favorite for grinding hedge trimmers