Tuesday, April 26, 2011

Micro Adjustable Grinding Jig

Today I finally got to spend a whole, uninterrupted day working in my new shop. It was fantastic! I've been looking forward to resuming shop life and I made sure to mix up activities to get all the juices flowing. In the morning, I assembled a continuous armchair and in the afternoon, I decided to pursue the grinding jig that Greg and I played around with at Kelly Mehlers.


Here is the finished jig and you can see the steps to making it below. I used spring pins for the bearing surfaces that the tool rides on. They are spring steel, so they will be hard enough to resist the wear of the tool riding back and forth without forming ruts. You can find them in the hardware store along with the bolt and locknut that form the adjuster.

To start out, I needed a dado cut across the block of cherry. Without a table saw or sliding mitre saw, I decided to pull out my trusty Stanley dovetail saw. Years ago, I filed the teeth off of this saw and refiled new ones that were a bit larger and did NOT set the teeth. Contrary to what you might expect, it doesn't bind and it cuts like a laser.
I've tried lots of the fancy saws out there, and maybe their handles are more comfortable, but none has surpassed my $10 Stanley. Don't get me wrong, I love that toolmakers are out there trying to make better quality saws, but I always feel like the teeth are too small and the set too great, but to each his own.

 I cut a center kerf and chopped out  most of the waste before bringing in my much neglected router plane (can you tell I was in the mood for fun!)

After a tiny bit of cleanup on the dado walls, I cut the sliding block that holds the pins. As you can see, I mounted some aluminum angle on both sides of the block to capture the adjuster bolt.
The notch out of the bottom of the block and the small slot out of the back serve the same purpose, namely to increase the travel past the aluminum. I suppose I could have done two notches or two dados, but I was in the zone and working on the fly.

I put the block in the slot and marked the position of the bolt, through the holes already drilled through the aluminum on both sides of the adjuster block. It's a good idea to offset the bolt hole just a hair above the holes in the aluminum to create tension against the bottom of the slot. This will create stability and help keep it from vibrating out of position.

The bolt easily cut threads through the cherry block.

Then I drilled for the pins. The vertical pin is only partially housed.

Here, you can see the horizontal pin inserted into the hole beneath the vertical. I used the grinder to trim the length of the horizontal pin afterward, and pared back the face of the block to give more clearance around the vertical pin.

Here is the whole unit clamped to the tool rest. I used the gross adjustment of the wolverine jig to start and then turned the bolt to fine tune the setting.

It's very important to note that the back of the drawknife, which rides along the pins should be filed clean and smooth. The grind will only be as straight as the the back. Luckily, most blades are soft along the back and easy to file and polish.

Here is the grind, I am very pleased. I loved being able to control the angle so precisely.

And for the farm enthusiasts out there. It's an amazing coincidence that Sue and I moved just a mile or so from a Heifer International Education Farm. We have been frequent visitor to see the births and visit their lovely herd of goats.

Here are some of their new additions. We just stand there grinning like idiots.
It seems like these kids are born knowing something important, when the sun shines on you, stop what you are doing, close your eyes and enjoy.


Tee said...

Awww! I would be right there with you grinning as well. We recently visited friends in North Georgia that have goats (chickens, cows, dogs and a cat) and I was in hog heaven, so to speak. I could so live on a farm.

Peter Galbert said...

I knew I could elicit a comment from you with these guys!

R Francis said...

Peter, I am being stupid are the spring covers just held by friction in the holes in the block. And what makes them stay at right angles and touching when you put the back of the drqwknife on them?

John said...

I love that you guys have the goat farm. Our friends have been trying to convince us to put some on our land, but we haven't made the plunge yet!

Peter Galbert said...

the pins are indeed held in place by friction. The vertical one is only partially inset, as you can see in the image but the horizontal pin goes about 1 inch deep into the block. There's nowhere for them to go. Lemme know if this needs further clarifying!

Beware, goats are a slippery slope, you can't just have one!! Every day they make me smile and the little care that they take is simple. The only hassle factor is getting someone to goat sit when we travel. If it's just for a day or two, we stock em with hay bales and an auto waterer. I hope to breed again at the end of the year, the whole experience of kidding and milking was fantastic. Good luck,

Anonymous said...

Hey Pete,
Wondering if you could do a short video of your new jig while sharpening your drawknife. It would go miles for me to see and hear you talk about it in video form...


Peter Galbert said...

I'll make the video once I find my tripod, you haven't seen it since the move have you!??

Linden said...


I'm getting ready to make this jig, with one modification. The bolt that I'll use will be a full thread carriage bolt mounted backwards, with a wing nut on the outside (operator side). I'm hoping that this will allow adjustments with no need for a screwdriver, plus, give a visual indicator of slight incremental changes.

An easy retrofit for your jig also... I'll send photos and report.

Thanks for sharing your design!


Peter Galbert said...

sounds great. There are a million ways to skin this cat, I figured someone would advance the idea. I look forward to seeing the results,

Anonymous said...

Hi Pete
do you stop during the grind to cool the blade in water?
it looks a beautiful grind

Peter Galbert said...

Generally, needing to quench the blade is a sign that you are using too much pressure or that your wheel needs dressing, which reminds me that I have to order a new 8" wheel, mine is down to about 5"!