Intro: Machining a Finger Plate Clamping Tool
If you're looking for a new project for your mini lathe and mini mill, then look no further; you've just found it. Not only will it give both machines a good workout, but at the end, you will also have a great little tool to use in the shop.
All those fiddly little parts that usually defy holding, can be clamped securely to this tool, and then you can work with the tool either "hand held", or lock it down on a vise. It makes life a lot safer on the drill press.
It's surprising how often you need to put a cross hole in a thin rod section so it also has a very useful cross-hole drilling jig built into it, to make that job easier and quicker.
There are plans available for purchase at the Clickspring website, but if you are feeling adventurous there is no reason why you can't simply use the concept presented here and then make it using items that you already have in your scrap box. It can also be scaled up or down according to the sort of work you do.
This tool is usually associated with clockmaking, but it really is a must for every home shop.
(Refer to the drawings for dimensions, or simply modify the design to suit what you have in your scrap box)
- 1 x Block of scrap steel for base approx 3.5" square, 3/4" thick
- 2 x 2" length of 5/8" mild steel rod
- 1 x 1" x 3.5" section of 1/4" mild steel plate
- 2 x 2.5 lengths of 1/4" threaded rod
- 1 x 1" length of 1" diameter brass rod
- 1 x 1" length of 1/2" diameter brass rod
- Metal adhesive
- Layout fluid
- 400 grit emery paper
- Milling Machine
- Drills and taps
- Calipers or Micrometer
- Hand files and finishing tools if desired
Step 1: I Love It When a Plan Comes Together...
You can certainly make this project without a set of drawings, and you certainly don't need to have a fancy CAD layout either. But I recommend that you at least scratch something down on a pad to get yourself organised. Even better, buy a set of plans from my website and get the warm feeling that comes from knowing that you're helping a budding Instructible's creator keep the lights on...
Either way, have an idea of the layout of the tool.
The only really critical aspect of the design is that the cross-drilling jig must be dead on the centerline of the V-groove for the jig to give a good result. Other than that, make it the way you want it.
Now is also good time to assemble all of your materials too, and square up the stock for the base if needed. I used a rough plasma cut scrap for the base for mine, so I took it to my metal cutting bandsaw and trimmed up the edges.
Step 2: Mark Out the Base.
Apply some layout fluid to the metal base, and mark out the hole positions and the centerline for the V-groove. Also mark out the 60 degree V shape cut out.
Center punch the hole positions.
Step 3: Drill and Then Tap the Threads for the Base.
Hold the base on the mill in a vise, and drill out the hole positions as per the plan, and then tap the center hole for the threaded rod.
As a general rule, if I want a larger hole to be both accurately positioned and have a nice surface finish, I will start the hole with a series of drills, and then finish off with an end mill. The end mill is much stiffer, and has a lesser tendency to 'walk'.
Step 4: Groovy Man...
The V groove is the most critical part of the job, so it requires a bit of attention in the setup.
Using whatever angle setting method you prefer (I like angle blocks), set the work on a 45 degree angle and hold the work securely in the vise. Touch off the outer tip of your end mill precisely on the centerline of the groove, and then note the settings on your handwheels (or zero your DRO if you have one).
You will then feed in, and down exactly the same amount for each cut to ensure that the centerline of the groove is cut where it should be.
Take your time, and use a pen/paper to keep track of your moves as you cut.
Total Infeed = √(2 x groove depth)
Use the band saw to rough out the 60 degree cutout, and then clean up the cut with either a belt sander, or hand files as required.
Use emery paper to give the desired surface finish, and break all sharp corners too.
Step 5: The Cross Hole Jig Insert
The drill bushing jig is an interesting little part.
I'm going to direct you to the video for this one, because it really is much easier to watch the process, than to explain it in writing.
Check your progress on the outside diameters using the holes you created in the base as your gauge. You want a snug fit, but not tight.
Once completed, bond the part in place using a spot of metal adhesive. Be sure to confirm that the alignment is in line with the groove.
Step 6: Threaded Rod Inserts
There are 2 threaded rod inserts in the tool; One for the center stud, and one for the lifting screw.
Cut off both to length, and then trim the ends to a nicer finish on your lathe.
One can be bonded into the base of the tool using adhesive, and the other can be set aside for later use with the lifting screw.
Step 7: The Clamping Nut
Knurl the outside of the stock, and then turn the profile. Drill and then tap the center hole, and part off. Rechuck the other way around and tidy up the cut surfaces.
Step 8: The Clamping Finger
Paint the surface of the steel with layout fluid, and mark out the shape of the clamping finger.
This part is symmetrical, so it's perfect for laying out using the center line of the part to help you along. The video shows what I mean.
I formed the center slot using the milling machine, however there is no reason why you couldn't do this with a jewellers saw and files - that's how I made slots before I purchased a small mill. It will take you longer, but you can get a very good result.
The outside shape of the finger is best formed by roughing out the waste stock using a saw, and then bringing it to the line using a powered sander of some sort. (I used a 1" belt sander)
Again, you could do this by hand with a saw and files, it would just take longer.
Use 400 grit emery to give a nice surface finish.
Step 9: The Lifting Screw Thumbwheel
This part is made in a very similar fashion to the clamping nut.
The interesting difference is that once it's parted off you'll need a way to hold the work so that you can turn that parted off surface. I used an appropriately sized cap screw as a mandrel, and screwed the work onto that.
You'll note on the video that I turn the dome section using a hand held graver.
A graver is a traditional and much used tool in the field of watch and clockmaking. It functions much like a wood turners lathe tool, but on a much smaller scale. It is one of the most satisfying ways to shape metal on a lathe, and can be used very precisely.
I will be making a video on the use of gravers in future, so be sure to subscribe to the Clickspring YouTube channel to be aware of that when it gets released.
Step 10: The Drilling Jig Bushings
These bushings are an elementary turning exercise. You can make these as you go along - when you need a particular cross hole diameter drilled, just turn one up on the lathe. Before long you will have a good collection of commonly used sizes.
I stamped the sizes on mine, just to keep track of what sizes I have.
Step 11: Assemble and Enjoy!
Try it out on the drill press and see what you think. It takes a moment to adjust to the feel of the weight of the tool, but before long, you will wonder how you ever did without it.
In my opinion, the drill press is by far the most hazardous machine in my shop, and this tool goes a long way toward addressing that hazard.
I hope you've enjoyed this Instructable. I think you'll really enjoy building the tool, and the tool itself will certainly be one of your most used.
If you liked this Instructable, or if you can suggest some ways to make it better, let me know in the comments below. Also, be sure to subscribe to the Clickspring Youtube Channel, for more tool building videos.