Harold Hall's Faceplate and Angle Plate Clamps

[Sailplane Driver]

Well, machinists are a pretty opinionated bunch, and you definitely have a lot more machining knowledge and experience than me (your post history is great),
but "this Hall fellow" is a pretty well respected author of a very large number of books and articles on model engineering and machining in general. I think he is or used to be the editor of the Model Engineers Workshop magazine in the U.K. To me, he's right up there with George H. Thomas.

What clamping method do you recommend for faceplate work? Mr. Hall's clamping system seems reasonably compact to to me. I'd be hard pressed to come up with anything more compact other than super-glue on freshly faced aluminum, but I'm still learning. (I use-super glue all the time for small one-off parts and light cuts, but its kind of a pain to clean up, especially with multiple setups.)

Seriously (no disrespect at all): if you have a better suggestion for faceplate clamping I'd also like to see it.

With respect to the original question, I'd recommend a "one part a time, one operation at a time" approach for a project like this (or almost any project). Definitely do not bore a deep hole through a long piece of stock as the first step before cutting pieces to length! Drill bits tend to wander, and deep boring jobs are a PITA anyway as you have to keep retracting the drill to extract chips. You can sometimes get away with drilling all the way through and then parting off multiple parts, but it's also easy to get into trouble that way.

For example, I'd machine the packing pieces as follows:

1. Chuck up a length of material in a three jaw chuck, with about 1/8" more than dimension A extending from the jaws.
2. Face.
3. Center drill, then M6 drill to a depth slightly deeper than dimension A.
4. Chamfer the bored hole slightly with a 90º countersink (to remove any burr).
5. Break the edges with a file.
6. Part off at dimension A. (Remember to break the inside edge with a file before parting all the way through.)
7. Extend more material, then repeat steps 2-8 for the number of parts desired. (Parts will already be spotted, though, so no need to center drill)
8. Flip and re-chuck each part to chamfer the hole on the other end with the countersink.

This completes the first operation, creating center-bored parts of the correct length. The second operation would be on the mill to bore the non-centered M6 hole. I'd do it as follows:

1. Insert the part in the vice. Use a v-block, parallels, and vice stop to repeatably hold each part in the same location.
2. Position the table to drill the offset hole.
3. Center drill, then M6 drill through the part.
4. Chamfer the drilled hole with a countersink.
5. Repeat steps 3 & 4 for each part.

The third operation is also on the mill to create the step. I'd create a super simple fixture out of aluminum to orient each part: just drill two M6 holes the correct distance apart in a piece of aluminum, then use pin gauges (or drill bits) slightly smaller than holes to align the parts before clamping them in the vise. After milling the step in each part, I'd do the final countersink chamfering and de-burring of the milled step edges by hand.

There are almost certainly more and better ways to do it, but that's how I'd approach the job. The idea is to make set-up changes between operations, as much as possible, rather than within an operation.

Hope this helps.
--
Rex

Thanks Rex, that is exactly the type of input I was looking for. I took a class at our local community college but they didn't go into work holding or sequencing in much detail. The program was geared more to getting into CNC than traditional machining.

I like your idea of the alignment fixture. I was trying to figure out a way to do keep alignment without having to change from a drill to a mill for every piece. I can turn down a couple of pins easy enough.

I'm still tempted to drill (not bore) the center hole through and part off using a horizontal band saw rather than parting off each piece. My 7x12 lathe does not like to part very well compared to the much larger lathes I used at the college. Could be the type of QCTP I have and the resulting overhang - the tool gets cantilevered well to the left of the cross slide. It is the Harbor Freight QCTP and I can see the tool post lean because of things flexing when I cut off. I guess I could try using the original tool post for cutoff operations as an alternative.

I've cut the round stock down to 4" lengths for groups of parts. How bad do drills wander over 4" if you use a center drill with a reasonably well aligned tailpost? These clamps do not have critical tolerances.

 

[Sailplane Driver]

I suppose this sort of clamping arrangement is for those of us who don't own a milling machine. The bore in the example pic on Harold's site is a simple thing to do with a boring head. As Wreck implies, it would probably safer and more accurate as well.

Thanks, mikey. I just bought a boring head - right after I bought the steel to make these clamps. I figured I would build them anyway since it looked like a simple and worthwhile project.

 

[Sailplane Driver]

Workable but not ideal, any length of boring bar extension is unwanted, keep the extension to a minimum. You have I suspect read that the rule of thumb is not to extend the work or tool more the 3 diameters, this is often impossible with boring operations. Boring tools are often made from more rigid materials for this reason, solid carbide shank bars are excellent for boring many diameters deep, anti vibration tooling also allows deep boring. This increases costs however.

In this case the excess threads and nuts are 2 or more bar diameters themselves, thread the clamps and bolt from the back allowing the bar to be held much deeper in the holder. At the very least use flat head screws.

It is possible that the author just threw it together for a photo.

If you look at the photos, Harold Hall is using tap bolts, bolts that are threaded the full length. I cannot get tap bolts in either metric or 1/4-28. That means that the bolt length will have to match the packing/busing combination and any thread extension beyond the nut will be minimal. 1/4" bolts 6 inches or less only have 3/4" of thread.

 

[Sailplane Driver]

Now with all this input, I'm getting confused as to the worth of constructing these clamps.

The claimed benefit is the ease of assembly and safety since they are captive to the plate. The packing is held firm to the plate before the clamp is tightened making it so you don't need three hands to mount something to the plate. Nothing gets thrown around the shop - hopefully - if a clamp comes loose.

Are these a good idea or a bad idea? How much distance do I lose using a nut at the back of the plate versus a nut on the face side of the plate? If we are talking about a few threads extending beyond a nut, is that much difference compared to a bolt head?

1/4" bolt head height = 11/64" or .172
1/4" hex nut height = 7/32" or .218
Add up to 1/4" additional for extended threads would give at most .300 extension compared to just a bolt head. Is that really excessive?

Are these the wrong direction for holding something to a faceplate? If so, where can I find information on the correct way?

If I have a boring head, will I ever need to use the faceplate? If so, then I don't need to make these at all.

 

[mikey]

If I have a boring head, will I ever need to use the faceplate? If so, then I don't need to make these at all.

I'll give an opinion and let the other guys tell me I'm full of it. I think using a faceplate is handy if you have no mill and/or boring head.

If you have a milling machine with a boring head then most things can be clamped in a vise or the mill's table with clamps and you can bore or otherwise profile your part. There may be some unique situation that may prevent this but I haven't run across it yet and I've been milling stuff for awhile.

 

[Doubleeboy]

Seems like the British model engineers were very inventive with lathe tooling. Lots of jobs that would have been done on a mill in USA were done by British hobbyist on the lathe , faceplates, angle plates, line boring with part on saddle. My hats off to their ingenuity, but for simple use, a boring head and a small mill sure seems easier. I am guessing that in last 20 years with the mini mill becoming prevalent in small home shops lots more jobs get done on a mill now that in past decades would have been done on lathe. Reading old Euro model engineering mags I get the sense the very few had mills back in the 40s-70s.

 

[george wilson]

I usually find it quicker to super glue small work rather than assemble all the stuff as seen in the picture. You could super glue the part to a larger piece of metal and possibly get it centered up using the independant chuck jaws. The work need not be put way back in the jaws,against the chuck body. A parallel faced off piece of metal could be used to make sure the work is parallel to the chuck's body. Then,removed when you get the work centered up.

I do not find super glue real difficult to remove. Some carefully applied heat,and you can get it into a rubbery state where you can peel all or most of it odd. A little soaking in acetone can get the rest.

 

[Rex Walters]

I'm still tempted to drill (not bore) the center hole through and part off using a horizontal band saw rather than parting off each piece.

I was getting lazy with terminology and talking about using drill bits to bore holes in metal. Sorry for the confusion.

I'd still strongly recommend planning your operations to minimize the depth you need to drill. I'd cut the parts to rough length in the bandsaw, then drill each piece individually. You'll get more accurate holes and not have the hassle of continually clearing chips. Deep drilling before cutting to length wouldn't be my choice.

Just be sure to think operations through -- don't bandsaw or part off until you're sure you don't need that bit to hang onto in the chuck! Since your project has a lot of center holed parts, you can always use a piece of stock in the chuck, freshly faced with a tapped hole and a screw to hold onto your parts for outside turning. My process above eliminates the need for that, but requires the ability to part off.

I used to have huge headaches parting until I made a rear mount tool post (that holds a parting tool upside down). Now parting is a dream. Try it if you can -- incredible difference.

 

[Rex Walters]

Are these the wrong direction for holding something to a faceplate? If so, where can I find information on the correct way?

If I have a boring head, will I ever need to use the faceplate? If so, then I don't need to make these at all.

There is no such thing as bad experience. ;-)

Sometimes work holding / tool holding is easier if you fix the part and move the tool (mill with a boring head). Sometimes it's easier to move the part and fix the tool (lathe work).

Every project is a learning experience. Everyone has preferences, and I tend to avoid my (admittedly crappy) boring head on the mill. Most of the time I can bore a hole better and faster on the lathe. That said, I rarely use a faceplate -- if I can't use the four-jaw chuck on the lathe, I'd consider using the mill.

Still, I've learned far more building projects from GHT and Harold Hall, etc. than I have goofing around on YouTube or forums. Ending up with a nice tool is a big win for me regardless how often I use it! I HATE buying a tool I use once, but I've never once regretted making a tool.

 

[Sailplane Driver]

I was getting lazy with terminology and talking about using drill bits to bore holes in metal. Sorry for the confusion.

I'd still strongly recommend planning your operations to minimize the depth you need to drill. I'd cut the parts to rough length in the bandsaw, then drill each piece individually. You'll get more accurate holes and not have the hassle of continually clearing chips. Deep drilling before cutting to length wouldn't be my choice.

Just be sure to think operations through -- don't bandsaw or part off until you're sure you don't need that bit to hang onto in the chuck! Since your project has a lot of center holed parts, you can always use a piece of stock in the chuck, freshly faced with a tapped hole and a screw to hold onto your parts for outside turning. My process above eliminates the need for that, but requires the ability to part off.

I used to have huge headaches parting until I made a rear mount tool post (that holds a parting tool upside down). Now parting is a dream. Try it if you can -- incredible difference.

The parting tool I use has to mount upside down in the Harbor Freight toolholder since it is too high when mounted in the normal position. I run the lathe in reverse in order to part off. This tends to put a lifting force on the toolpost and cross slide - not desireable but what I have to live with. It seems to work okay for softer metals but has a hard time with steel. I need to either buy or make a better QCTP. Then again, I really should get a better lathe.