Magnetic jig

I'm looking at putting together a magnetic jig to hold blades that I'm restoring, mainly during hand sanding. I've seen Bill Ellis' and Rayman's designs which have given me some pointers...already got the rare earth magnets, a range of off-cuts to use as a base and a sheet of aluminium 0.032" thick to use as a heat-sink. Does anyone have any hints or tips they're willing to share? Preferred dimensions, extra features they find useful. I'll be attaching it to a Black and Decker type portable work-bench using a couple of coach bolts through the jig and the peg holes in the work-top. I'll post pics tomorrow once I've got things laid out.

Looking forward to seeing what you come up with.

I handled one that was put together by another member here "hornm" he may be able to help if you shoot him a PM.

I made mine from walnut. Here's a couple pics.

Paul, is that your jig in the hand sanding tutorial at SRP? If it is, thanks for a very informative and detailed thread. I haven't got a router but wondered if your design would work using a plane to make the "ledge"? I've got the small round magnets...I'll start with one in each recess to see how much hold it gives, then add extras if needed.

Pumpkin said:

Paul, is that your jig in the hand sanding tutorial at SRP? If it is, thanks for a very informative and detailed thread. I haven't got a router but wondered if your design would work using a plane to make the "ledge"? I've got the small round magnets...I'll start with one in each recess to see how much hold it gives, then add extras if needed.

Click to expand...

Yes, that's mine on SRP. I was really flattered that my ugly block was featured in that tutorial and the SRP Wiki page on restoration. Anything that would leave a ledge should work fine, or you could glue or screw another piece of something onto the main piece to create a ledge. The round magnets would be easy to inlay with just a drill of the appropriate size. Can't wait to see your creation!

PaulX608 said:

Anything that would leave a ledge should work fine, or you could glue or screw another piece of something onto the main piece to create a ledge. The round magnets would be easy to inlay with just a drill of the appropriate size. Can't wait to see your creation!

Click to expand...

I'm thinking along the lines of gluing a strip of wood across the top of the jig...I've got some 1/8" basswood that should give a "soft" edge.

The magnets are 10mm diameter, so I've drilled a row of holes along a piece of 6mm thick MDF (bottom left in pic) that I will glue across the pine base...this should give me plenty of depth to add extra magnets (if required). There's a stack of 12 of them sitting on the MDF!

The photo below shows the components laid out on the work-bench. Instead of coach bolts I've gone with a couple of cavity-wall fixtures (top left on top of pine block) that I had spare. Proper bolts would have probably been a bit TOO heavy duty!
I've countersunk the bolt holes, in the pine block (top left in pic), so that the MDF will lie flush. I'm going to glue the MDF in place. The toggles of the cavity bolts (just) clear the peg holes in the work bench so there's no need to remove them. The working area is 5" wide x 4" deep.

I haven't cut the aluminium sheet yet (right hand side of pic), just in case there were any suggestions
I did look at getting a sheet of copper to use as the heat-sink...but it was about 4 times the price at my local model shop!

Apologies for the mix of units...I'm a child of the 60's so I'm still not fully metric!

Pumpkin said:

I've countersunk the bolt holes, in the pine block (top left in pic), so that the MDF will lie flush. I'm going to glue the MDF in place. The toggles of the cavity bolts (just) clear the peg holes in the work bench so there's no need to remove them.

Click to expand...

Having just glued the MDF onto the pine block, I've discovered a (fairly major) flaw in this step! I should have applied a spot of epoxy/CA to the head of the bolt before covering it with the MDF Doh! I'll do a test run to see if I can still tighten the butterfly nut with the bolt turning freely. Hopefully it will grip a bit as it tightens.

EDIT: One held on it's own, the other bolt just spun freely. I've applied a spot of CA to the threads, where they come out of the base, hopefully that should hold things.

Here's the "finished" jig. It's ended up very close to Bill's design (credit where it's due).
The edges need to be tidied up a bit. The wood strip is 1/8" basswood that I've stuck down with CA, rather than epoxy, so that I can replace it if required.

I went with 2 magnets in each recess. I was worried that any more would make the razors "snap down" too hard...and make it too hard to get them off!

The spot of CA on the threads seems to be holding. With 20/20 hindsight I think that just drilling holes, for the bolts, in the aluminium would have been more practical. With this method I'm restricted to only using it on the work-bench. However, that should make for a happier home life as there will be no risk of me working on the dining room table again (the bench was an early birthday present from SWMBO, so it probably bothered her more than she let on! )

You don't need to go so large. 1 x 2 3/4 x 6 is as big as you'd ever need. Here are three ways to fasten the jig to a work surface.

• Drill and install wood inserts into the table surface in the position that you see on my pic of the finished jig. 10x24x1/1/4 machine screws will work fine to hold it down. The inserts are put into the tabletop with a hex key after drilling the hole the same size as the barrel of the insert. Find them in any hardware store.
• Fasten with glue or screws, a 1x1 wood strip on the bottom of the jig lengthwise and set it down into the jaws of that vise you already have on your worktable. The bottom of the jig sits against the top of the jaws and the fastened wood strip is between the jaws. Ain't goin' nowhere as long as the vise is securely fastened.
• Put 4 more magnets on the bottom of the jig near the corners. Glue an over sized thin piece of ferrous steel to the surface of the work table. You can also use those same type inserts to temporarily hold the steel to the table top. When you want to use the jig, just position it at any angle you want.

You got a bit more complicated than it needs to be. But, what works... works. Use what you are comfortable with.

BillEllis said:

You don't need to go so large. 1 x 2 3/4 x 6 is as big as you'd ever need. Here are three ways to fasten the jig to a work surface.

• Drill and install wood inserts into the table surface in the position that you see on my pic of the finished jig. 10x24x1/1/4 machine screws will work fine to hold it down. The inserts are put into the tabletop with a hex key after drilling the hole the same size as the barrel of the insert. Find them in any hardware store.
• Fasten with glue or screws, a 1x1 wood strip on the bottom of the jig lengthwise and set it down into the jaws of that vise you already have on your worktable. The bottom of the jig sits against the top of the jaws and the fastened wood strip is between the jaws. Ain't goin' nowhere as long as the vise is securely fastened.
• Put 4 more magnets on the bottom of the jig near the corners. Glue an over sized thin piece of ferrous steel to the surface of the work table. You can also use those same type inserts to temporarily hold the steel to the table top. When you want to use the jig, just position it at any angle you want.

You got a bit more complicated than it needs to be. But, what works... works. Use what you are comfortable with.

Click to expand...

Bill, thanks very much for the feedback...I'd agree (now that it's finished) that it's probably on the large size!

I hadn't even thought of using the vise...just saw the holes and tried to figure out the best way to use them.

Not too shabby!

I use mine all the time, fantastic idea, and it saves a ton on Band-Aids!

Having just used the jig for the first time, Bill is definitely right on the size (and my over-complicating things)!

Whilst I went to a lot of effort to make it fixable to my workbench, I've actually just used it hand held This was pefectly adequate for hand-sanding. However, when I switch over to a polishing mop attached to my drill, I think having the extra security and stability (and a free hand) will be a big help.