Planer Accurate Depth of Cut

[velocette]

Hi all Wood Nuts
Recently I bought a 150 mm wide planer in rough condition and spent a lot of time and a little money on a rebuild to use on my woodworking.
Once complete I figured that if I fixed a DTI to the In feed Table Gibs  then every 5 mm on the DTI  = 3 mm depth of cut.

Eric

[Spurry]

That's a very cunning solution to feed depth.  Do the vibes from the machine not affect the DTI when in actual operation?
Pete

[velocette]

That's a very cunning solution to feed depth.  Do the vibes from the machine not affect the DTI when in actual operation?
Pete

Hi Pete
Nothing detected so far with a heavy cast iron frame of around 30 - 40 Kgs. I lock the gibs and then take up the backlash on the adjustment to hold the table up.
The drive is with Poly Vee Belt 6 Ribs giving a very smooth drive. I do confess to being a Poly Vee Belt Drive addict with all bar one workshop machines with them fitted.
Eric

[Spurry]

Thanks for answering the query Eric.
Hope it continues to work well for you, so happy planing.
Pete

[ZebraDriver]

Eric. Nice set up, a couple of wee comments for you to consider:-

 If you mount the DTI vertically with the reader tip running against a horizontal block the reading will be direct rather than your 5mm for each 3mm Also I see you seem have two DTIs fitted, the outfeed table should be fixed at the height of the blades, if you don't have it set at blade height you will start planning curves.

Martin

[velocette]

Eric. Nice set up, a couple of wee comments for you to consider:-

 If you mount the DTI vertically with the reader tip running against a horizontal block the reading will be direct rather than your 5mm for each 3mm Also I see you seem have two DTIs fitted, the outfeed table should be fixed at the height of the blades, if you don't have it set at blade height you will start planning curves.

Martin

Fair comment Martin Yes  Two DTI's fitted However I posted pictures of Two different machines and failed to make comment. Look closer and one is mounted on a Black Frame the other on a Grey Frame.
To read directly the anvil for the DTI MUST  be parallel to the in feed table and have a polished surface
The Blades to the  out feed table is set up with a special jig to Plus or minus 0.05 mm of the blades at TDC so planing curves is NOT a problem.
The black frame was a recondition job and on sold the grey one is bolted to the side of my saw bench

Eric

[velocette]

 
Hi
Took your comment on board Martin and mounted DTI to measure vertical on a sliding block so much simpler 

Eric

[howsitwork?]

Good ideas there. The real fun comes when you start changing or sharpening the blades off the machine then need to remount. The magnetic jigs make it a bit easier but still an awkward little job.

Ian

[ZebraDriver]

Be careful when your changing blades.  I was recently sent to a job where the operator had failed to tighten one blade properly on a 12" Smith planer.  It had managed to get up to full speed before the blade slid out.  The blade shattered sending shrapnel everywhere but as it did it snapped the end 4" off the infeed table and managed to pull the mounts for the cutter block hard enough to tear them out of the casting below it!!. The operator who was standing next to it, luckily, didn't have a mark on him but I guess he had to go home to change his underwear.


Martin

[awemawson]

Odd . . . most planers have a wedge shaped slot, narrow bit to the outside, and the clamps are naturally also wedge shaped, so as they and the blades tend to fly out with centrifugal force the grip tightens. 

[ZebraDriver]

Not all planers have wedge shaped slots. The smith machine that I was working on has two large plates clamped on the side of the block. Each held with 4 studs (probably 5/8 or 3/4 whitworth).  The plates are machined to provide a recess so that they will hold a 1/8" thick blade but there is no wedge - the blades are held only by the pressure exerted by the studs/nuts

Even some of the Wadkin machines don't have wedges or wedge shaped slots.  The securing screws are angled in the block and the seat for the end of the screws in the "wedge" is angled but the ""wedge" itself is a parallel piece, as is the slot. We've just refurbished 3 9BFT machines for one of our customers  (another four to go) and they are all the same as this.

[awemawson]

I've just ordered a 12" travel remote indicating DRO for my Dominion combination machine that should aid determining thicknesser settings more accurately than previously.

Not arrived yet, but I'm hoping I can mount it at the side of the mechanical indicator picking up the current pointer with a custom 3D printed adaptor. the display can go anywhere as it's a magnetic mount 

[velocette]

Hi
Part of my job was servicing and setting up Tobacco Cutters that had 5 Knives mounted on a large drum that had automatic knife advance with a powered grindstone that advanced and dressed with a fixed diamond to keep the clearances correct.
Often wondered if this principal had been applied to a planer.

Eric

[ZebraDriver]

Some woodworking machines have dressing stones that can be used to give the blades an edge between sharpens, but I've never seen one that could advance its own blades. Perhaps this is one of these issues where one industry could learn from another.