Let's build a small infill smoother! #2: More Metalworking

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Blog entry by Ripthorn posted 02-20-2015 03:35 PM 2409 reads 0 times favorited 4 comments Add to Favorites Watch
« Part 1: Intro and Rough Metal Working Part 2 of Let's build a small infill smoother! series Part 3: Filling it in »

Alright, so last time we left off with some holes drilled and infills roughly cut. Before I could transfer the holes from the sides to the sole pieces, I needed to make sure that the mouth spacing would be right for my (anticipated) 3/16” thick iron. Now, you will remember that the sole pieces had the angles rough cut on a bandsaw. This actually did a pretty good job, but there were still marks that needed to be removed.

I decided that while removing the marks, I would also clamp the infill to the back sole piece. The reason for this twofold: first, to give the sole piece something to support it. Since this is a critical angle, I couldn’t just free hand it and get it “close enough”. Second reason is that this would ensure a nice plane (pun intended, as always) with the infill, reducing later effort in ensuring a level bedding of the iron. I started with 80 grit paper on the table saw top and used a single direction stroke. The pieces were held together thusly:

I then free handed the toe piece because the exact angle for chip ejection is not critical. I also took the opportunity to sand down the side of the infill to be flush with the sole piece, also to aid in fitting later on. With that done, I was ready to transfer the holes from the side pieces to the sole pieces.

Before I could transfer holes, I needed to set the spacing between toe and rear sole piece. Because I had lapped them to 220 grit, I didn’t have to worry about any additional material being removed. Because the sides are 3/16” thick, I ground a scrap piece to a bevel to simulate a blade. I used this to space the mouth correctly, leaving it dead on so that I could file it open a few thousandths later on (or to accommodate a slightly thinner iron). When the spacing was done as I wanted, I superglued one side to the soles. Let it sit for a few minutes, then I put the sole in the bench vise (firmly, mind you!). I used a transfer punch to mark the holes. Like so:

With the holes marked, we can drill the holes for the tap. Since my last infills, I have acquired a cam action drill press vise. I love this thing! They aren’t too expensive, and have a nice little step in the jaws, like built in parallels. I then went to town (with generous amounts of cutting fluid) to get this:

The super glue holds just well enough that you can handle it normally, but comes off with a decent tap of a hammer (this assumes you used enough glue and your surfaces are clean and flat).

Also since my last infill, I have acquired a hand tapping machine. Really it is just a fancy tapping guide. I got it cheap, but you can make a tap block from a scrap of wood really easily too. I proceeded to tap the holes. Of course I had to check to make sure all was well:

With both sides all tapped, I was able to mark out where I wanted to drill to secure the infills. They will be epoxied in, but a couple screws won’t hurt. This needs to be done very carefully, as drilling them wrong can make them slide when seated, which would ruin our work on the bedding. So out come the clamps again:

Both infills got drilled, but I am a little nervous, as the holes in one or two spots look ever so slightly off, so my game plan is to epoxy in place, let set, then use screws afterwards to secure the infills. With all the holes drilled, it was time to think about peening, so I made a buck from a 2×4:

So here is where things got interesting. I drilled and tapped for #8-32 screws and countersunk. However, the only flat head screws I could find were all phillips head. The problem here is that the point in a philips screw goes below the surface so far that you can’t really peen and sand perfectly flat. So I did a test joint using just threaded rod. It looked promising enough, so I tried it. I’m not a fan. That means it is time for

Lessons Learned

- Peening threaded rock is not fun
- You can leave the zinc coating on a screw or threaded rod and it won’t show after peening and sanding
- #8 screws are a little bit, but I chose them due to the fragility of #6-32 taps
- I’m going to try to get some flat head screws from online
- You don’t have to peen opposing sides simultaneously like you do with through rivets

So I think that on the next one of these, I am going to make the toe piece longer (at least another 1/2”, it’s only 1 1/2” right now) and I will do through rivets where the sole is drilled first, then the side pieces are marked and drilled from that. I like peening round rod, but not threaded rod. This will also allow me to not use a countersink, but just a reamer. That means less peening and therefore less risk of a void.

Time to this point: ~5 hrs

Next up: peening and epoxying in the infill.

-- Brian T. - Exact science is not an exact science

4 comments so far

View terryR's profile


6733 posts in 1970 days

#1 posted 02-20-2015 04:22 PM

Thanks again, Brian! I’m amazed at the simple tools you are using!
Maybe I really can pull off something similar?

Thanks for sharing all the info and photos!
You’re a little over my head, but I’m trying to keep up!

-- tr ...see one, do one, teach one...

View Ripthorn's profile


1433 posts in 2646 days

#2 posted 02-20-2015 04:25 PM

Terry, if guys working 150 years ago can do it with their tools, I can probably manage with what I have :). I like sharing this stuff because there isn’t a whole lot on step by step infill making out there. Not only that, it helps keep my thoughts organized and serves as a reference to me when I want to check a detail or something.

I’m sure you could pull something off. As long as you have a way to cut, some sandpaper, a drill press, and a hammer and some files, that’s really all it needs. I want a stationary belt sander, but we’ll just have to see how that goes.

-- Brian T. - Exact science is not an exact science

View terryR's profile


6733 posts in 1970 days

#3 posted 02-20-2015 04:48 PM

Terry, if guys working 150 years ago can do it with their tools, I can probably manage with what I have :). I like sharing this stuff because there isn t a whole lot on step by step infill making out there.
- Ripthorn

I suppose that’s an excellent point! No power tools required really.
Thanks for sharing your methods…very beneficial for other newbies!

-- tr ...see one, do one, teach one...

View Don W's profile

Don W

18314 posts in 2229 days

#4 posted 03-14-2015 05:22 PM

I always use flat head screws or bolts. The Philips just won’t cut it.

Excellent tutorial.

-- - Collecting is an investment in the past, and the future.

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