I recently decided it was high time I quit cursing my micrometer carriage stop, and actually make myself a bracket for mounting a dial indicator. I had a dial indicator on my previous SB lathe, and it was a very useful accessory. While a positive stop for the carriage is sometimes preferable, I?ve found that for most of my work, the dial indicator is much more useful for easily and precisely locating the carriage along the ways.
Such brackets can be readily machined from metal bar stock, but I prefer the Metal Lathe Accessories MLA-8 indicator/saddle stop bracket, for its streamlined design and classic look. It?s a fun little project that can be completed in a couple of evenings. And for those of you out there who don?t like machining cast iron... fine, I say, that leaves more for the rest of us!
If you have never machined an iron casting before, it can be a bit of a challenge to figure out the best machining approach. One has to carefully judge material allowances, and pay close attention to how the UNmachined surfaces relate to those which will be machined. It?s a kind of knack that one slowly develops with experience, and I actually enjoy the challenge. This project, being fairly simple and forgiving, makes an ideal first project for the novice.
The MLA-8 bracket casting has a very generous machining allowance to fit a variety of bedway sizes and configurations. I found that the simplest way to transfer the bracket contour to the casting was to start with a paper template, trimmed to fit the front bedway, and marked with the approximate location of the indicator centerline:
The bracket contour can then be traced on the casting, such that the indicator location is centered on the round casting boss. This is just to get us close -- there will be a bit of cut-and-try when the time comes to fit the bracket to the bedway.
To accurately machine the V-way contour, I clamped the bracket in the vise using a 45° angle block. With the bracket clamped lightly in the vise, I placed a 1-2-3 block across the jaws, secured in place under light end mill pressure (padded with a scrap of leather), and offered the angle block up to align the bracket:
This setup worked pretty well. After getting it machined as close to the line as I could, I removed the bracket and offered it up the lathe bedway -- close, but not quite there. Back to the mill for a tweaking cut, and that was all it needed. The bracket slid very easily along the front V-way.
The rest of the machining operations are fairly straightforward. I deviated slightly from the plans in moving up one size on the cap screws (1/4 & 5/16 instead of #10 & 1/4), but only because there was ample clearance, and it seemed more ?proportional.?
If you don?t have a slitting-saw for your mill or lathe (as I don?t) the indicator clamp barrel can be slit with a bandsaw. I bolted the bracket to the end of a 1-2-3 block, using the clamp bolt hole. Here?s what that setup looked like:
Be careful to block up the saw, or place a piece of scrap in the indicator hole, so that the saw blade doesn?t mark the opposite side of the indicator hole when it cuts through.
The clamp shoe is a simple part to make. You may have to machine an eighth of an inch or so off of one end, to clear the carriage rack, as I did. The plans call for the 1/8? dowel pin to be pressed into the clamp show, but I pressed mine into the bracket. No particular reason -- just made more sense to me.
I painted my finished bracket to match the lathe:
My next challenge: save up for a 2? travel indicator!