Thread: Sharpening Thicknesser Blades

I use a "surface" grinder from Timbecon to sharpen my thicknesser & jointer blades. Works for me.

It sure beats the 80k round trip each time for delivery or pickup. Not to mention the customary minimum 7 day wait (if you are lucky)

Ken

ShocK horror for all the purist members,

But I just sharpen mine up freehand on the bench grinder

Bob you have a good eye and steady hand, I envy you.

I certainly don't get them as straight as a dedicated machine or a jig would but they do work well. Slight discrepancies are minimised as its unlikely they will occur in the same locations on both blades.

I cut a 3mm slot along a piece of pine. I just jam the blades into the pine to make it easier to use on the bench grinder

Derek Cohen posted a thread on sharpening plane blades on a bench sander.
With some modifying I'm sure it could handle thicknesser blades.

There is not a hope in hell I'll ever sharpen my own blades. I have seen what happened to a jointer after a blade came lose (a mates joinery). The accident was attributed to blades that were not professionally sharpened & had a significant weight difference between blades. (from QLD Work Place Health & Safety Dpt investigation) There were some minor injuries to 3 people. It could of been worse if a narrower piece of timber was being run. The timber was almost full width of the 16" jionter & acted as a guard.
This seems to be common with non-pro sharpened blades, according to the Dept.

If it's feasibly possible have your blades professionally sharpened!

I'd have to agree with MajorPanic, I'd rather spend the few dollars and have thicknesser blades done professional.

I do have a Tormak wet stone grinder, but the jig for it to sharpen such blades is $250 odd, mainly because of the precision of the jig.

my thoughts anyways

Major , when you live in the sticks you learn to do things city slickers like you take for granted.

BTW I have seen a jointer explode due to a knife coming loose.
Not a nice feeling to be close. I was about 10 feet away when it went bang.
I remember hitting the ground immediately and laying flat while looking for the off switch.

I'll hafta remember to balance the blades by weight, its easy enough to do but it will eliminate or minimise harmonic vibrations.

A real problem with any sort of sharpening involving the brittle mixes used on many moulder/planer blades is heat build up & stress cracks. Just went through this at work and the minutest of difference in technique can have disastrous results in use. Fixing the results of wayward shards of high tungsten content steel is a sobering task, so you Blokes be really, really careful, cause I'm a country Bloke, born with a piece of #8 in my mitt, and I will never do these freehand again especially without running coolant.

I have a Tormek and the jigs. I think it is worth it. Now I can sharpen my jointer knives and thicknesser knives whenever I like. More importantly I can sharpen them as often as possible when I don’t have to worry about another $70-$80 for a set of 6 blades.

Having sharp blades all the time will only benefit your machines and work quality.

I have a woodcraft 12" thicknesser and to re sharpen the blades I ran two grooves the same depth into a block of wood at 47* the angle on the original blades

When the blades are in the block the two cutting edges are then parellel and can be honed touched up relatively easily
Or if realy bad done on a belt sander if its long enough,

I've used a jig like Ashore's to hone my planer knives for many years. On mine, the slots are parallel, and about 75mm apart, a couple of degrees less than the grind angle, so I can put a microbevel on easily. I use it to clean up the knives when they come back from the sharpeners (they leave 'em a bit rough for my liking) & re-hone them several times between regrinds, only sending them out again when the micro-bevel gets a bit too macro, (or I plane a nail ). Works very well for me.

The thought of exploding knives doesn't thrill me at all. Sounds plausible that uneven heating and stress cracks coupled with imbalance vibration could do it, but my Hitachi blades are great chunks of soft steel with a thin tool-steel insert for the cutting edge, so they would be pretty unlikely to blow, I'd hope. Mind you - my blades don't always come back from the sharpeners quite as well-balanced as I'd like - is there a rule of thumb about what percentage diffence is tolerable? (My manual doesn't even mention balancing knives - I guess they assume that'll be taken care of automatically.)
Thinking about it, probably not. There are too many variables such as actual size & weight of knife and diameter of the cutter block. My cutter block radius would only be about 25mm, and a few % difference in knife weight certainly doesn't cause any noticable vibration or affect quality of cut.

Cheers,

Hey Wongo, do you have the really real tormek jig? $250.00 is a fair load of money, I was wondering if a homemade variation could get the accuracy required.

Outback,

I did make the jig just like ashore’s one. I thought it was a great (clever) idea at the time. It worked well but boy it was a mighty effort to do 1 jointer blade.

Yes $1100 for the lot is a fair bit of cash but hey sometimes you just need to have one.

Originally Posted by Wongo

Yes $1100 for the lot is a fair bit of cash but hey sometimes you just need to have one.

youch!
You could have a Domino for that price. Then you would save time on joinery and sharpening jointer blades.