Thread: An idea for a contact grinder.

I thank you for sharing this.
Unfortunately, as Geezer can attest to, my mechanical aptitude is 0!
If you ever make a short video of your process please send me a link.

Originally Posted by randydance062449

I thank you for sharing this.
Unfortunately, as Geezer can attest to, my mechanical aptitude is 0!
If you ever make a short video of your process please send me a link.

I'm planning on working on it tomorrow. I'll try and shoot some video.

I am enjoying this thread, I admire your process and the way you are going about things. It is very well thought out.

Originally Posted by Voidmonster

Here's a visual of how I'll use it. The guide is just the stick itself and the way it holds the blank.

Attachment 303661

Added for clarity:

All the stick is doing, really, is protecting the part of the blank that will become the spine and shoulder, so all I can grind on is the blade face.

Man I'm loving this thread!
Inventing/engineering/designing is something that I enjoy doing. Even if its been done, its interesting to note that many of the "lost" ways are realized again as the process takes the most logical and "human created" steps to completion..
Basically, the same reason completely unconnected people on opposite sides of the planet will invent the same things, and develop the same methods.
I was drawing out similar plans for a blade jig and so am excited to see this development in your project! Yours looks way better than mine, more professional.
Have you considered a track for the jig to slide on?
I like Richard's suggestion on jig material.
Also Jerry said something, let me see if I'm getting it right: attaching metal in spots of high friction? Perhaps stainless sheet, or bumpers?
Perhaps this would minimize variance over a number of blades, and instead of replacing the whole jig, a new sheet or bumper can be replaced..?
Various jigs and track assemblies can be made depending on what part of the blade needs to be ground, to hold the blade different and move it past the grinding wheel in just the right way.
Seems very repeatable.
Thanks for the updates, good stuff here!

Watching and learning. Although I may never join in, it is fun to learn things from the ground up. I really like the traditional look Zak!

Originally Posted by MikeT

Man I'm loving this thread!
Inventing/engineering/designing is something that I enjoy doing. Even if its been done, its interesting to note that many of the "lost" ways are realized again as the process takes the most logical and "human created" steps to completion..
Basically, the same reason completely unconnected people on opposite sides of the planet will invent the same things, and develop the same methods.
I was drawing out similar plans for a blade jig and so am excited to see this development in your project! Yours looks way better than mine, more professional.
Have you considered a track for the jig to slide on?
I like Richard's suggestion on jig material.
Also Jerry said something, let me see if I'm getting it right: attaching metal in spots of high friction? Perhaps stainless sheet, or bumpers?
Perhaps this would minimize variance over a number of blades, and instead of replacing the whole jig, a new sheet or bumper can be replaced..?
Various jigs and track assemblies can be made depending on what part of the blade needs to be ground, to hold the blade different and move it past the grinding wheel in just the right way.
Seems very repeatable.
Thanks for the updates, good stuff here!

My plan is to make a proper contact grinder (which I'm initially going to drive with the lathe, since it's got a DC induction motor with continuously variable speed and it'll be trivial to stick a pulley between the chuck & a live center), and when I do that I intend to make attachments for a wide degree of template-controllable movement restrictions. For now though, it's just going to be the simplest one.

As for the high friction areas, I'm initially going to deal with that simply by making the sandpaper on my drum a teeny bit too narrow so none of it sticks off the edge and comes in contact with the jig. If I'm getting any notable wear on parts from that, I'll probably cut some delrin disks to go on the ends of the drum.

Here's a video of the washer punch in action with some explanation of the setup.

It would have been done yesterday if it hadn't gone something like this:

• Shoot video
• Review footage and see unusable bits
• Reshoot video
• Notice other bits have become unusable in different ways
• Reshoot video
• Get annoyed with the milling vise sliding from vibration
• Take what I've learned from breaking down the lathe to making the milling vise work better
• Notice that the offcenter vise dislodged the part I've been demonstrating on
• Make new part
• New part works differently because the old part was made before I drilled out the center hole in the punch
• Get everything working
• Reshoot video
• Edit video
• Upload will take 4 hours
• No, one minute
• VOILA!

Thanks for posting! I'll have to watch more of it when I get home.

Thanks a bunch !

You might also notice that one of the washers in the preload image of that videos is a little... Pockmarked.

Let that be a lesson to you all to clean out your receiving die before making anything! There was a bit of crud in there when I made that one and the method faithfully copied it in brass.

Edited to add:

Or DON'T clean it out for that authentic Old Sheffield touch! (Says the guy who's looked at a lot of old Sheffield washers under magnification)