Opportunity came knocking and I answered. A small horizontal milling machine became available. And now it is in the basement!
An unknown brand, it has 3 speeds and metric lead screws. Divisions on the handles are 0.1mm, approx. .004 inch. A solidly built machine, it is in good condition showing little wear and no abuse. I might repaint it machinery gray at a later date but for now I want to get on with using it.
I stripped the machine to components, cleaned and re-assembled. No bad surprises, old oil and metal chips were easily removed with Varsol. There are just a few Allen bolts and set screws to replace.
The spindle is 1.125-12, a match for Myford and others. It is a solid spindle which is a pity as a MT2 taper with draw bar would get some horizontal clearance back. The unit probably weighs over 120 lbs., it doesn’t move once placed on the bench. Operation is very quiet and smooth.
The ER32 collet chuck came with a 3/32” collet enabling me to try cutting some mystery aluminum with an 1/8 milling cutter. I am ordering some more collets to fit my various end mills. For the .75” and 1” diameter ones I will have to make my own arbors from 1.75” diameter steel, that will go onto the Tools-To-Make list.
There are a few machining steps coming up for the Jan Ridders Glass Cylinder engine that require larger pieces to be machined than will fit int he milling vise. A usual solution is a T Slot table to bolt onto the cross slide or milling slide but there isn’t one available in Taig size. Some time ago I bought a bunch of metal from someone, including a large piece of 1/2″ cast aluminum plate. A 5 minute cutting session on the bandsaw resulted in a 4” x 5.25” plate.
A bit of layout work and off to the drill press. Given that there is a grid of 20 holes to drill and tap I made use of the recently built fogless coolant sprayer to keep the drill bit cool and lubricated. The drill press was used to guide the 10-32 tap into the holes, finishing the tapping in a vise.
Last I drilled 4 mounting holes to line up with the T Slots on the Taig cross slide and milling slide.
I don’t have a #10 counterbore and the 10-32 SHCS’s I have are too long so 2 more tools go on the build list before I can finish this plate.
Cutting metal always works better when you apply cutting fluid (except cast iron, which you cut dry). It lubricates as well as cools the cutting tool. Serious machining usually uses flood coolant, which is very messy. A better solution for the small machine shop is a fogless coolant sprayer.
These basically mix air flow with a trickle of fluid. The better ones pressurize the fluid as well as the air. The design is very simple, 2 holes to let air and fluid into the mixing block, a .040 hole lets fluid into the air stream. As .035 hole in the end of the nozzle and you are done.
A visit to eBay for parts, Home Hardware for a 1/4-18 NPT tap and off to the workshop.
I made a hose barb fitting from some scrap brass to match the one for the coolant intake filter.
The various parts, the block is not finished yet.
The block is now cleaned up (edges chamfered to 45°) and 2 mounting holes counter-bored, using a 5/16 end mill.
After more than a year away from hobbies, I am back! In meantime we moved into a fabulous house, with 2 workshops! One for wood, in the garage, the other in the basement for electronics, models and machining. Pretty close to utopia for me.
First some catch up from July 2014. Having made the cylinders and pistons, the next item is the cylinder block. A nice chunk of brass was squared up with a 3/8” end mill and then marked up for the center of the combustion chamber. The block was then centered in the 4 jaw chuck and drilled out. I started boring the hole larger but the boring bar has the wrong back rake for brass, resulting in a mess! I left things here as we were packing up the condo in preparation for our selling it.
Rolling forward to the present:
Having access to all my tools is so empowering. I made a new HSS boring tool with geometry to suit machining brass. This solved the issues I was having while boring out the cylinder block to fit the glass cylinders. They are a somewhat lose fit to allow the Loctite 603 to do its job, and to prevent the block from cracking the glass once it heats up during operation.
I also bought the rest of materials that I needed for this project. The supports were not the same width so I fly cut them to be the same. The usual mess of chips flying everywhere but they are now within .002” end to end. Due to the small work envelope I had to shift the pieces 3 times to machine the entire 6.2” length. Thanks to the very solid milling vise this works out well.
We now have a working 3D router built up from a set of 3 Velmex positioners from the 1990’s. The built in limit switches are also connected. With Sonny Jeon’s excellent work on Grbl over the past year this is now a fabulous combination.
A short video of the first real cut. There is still some packaging work to do and it needs a control panel, esp. an E-Stop panic button. Router bits are on order from Richon Tools. These are inexpensive, a factor because I expect to break a few while figuring out the optimum cutting speeds, esp. for aluminum.
Grbl runs on an Arduino Uno but has no user interface. Instead you need to use a sender program. I tested out a bunch of different ones but the best for our purposes is Universal Code Sender. This program runs on various Windows, Mac and Linux. It provides various controls such as jogging and a file loader to send the actual Gcode cut program to Grbl. And it provides a cut visualizer.
The Grbl site has a copy of UCS but it is out of sync with the .9G version. So I installed NetBeans, , replaced the out-of-date RXTX library that is in the git source and compiled UCS 1.0.8. It is rock solid when run by double clicking the .jar file, no communication errors as before. (I do not use the start-windows.bat file, an open Command window seems to affect behaviour.) All testing is done on 64 bit Windows 8.1
I am presently blocked on the Glass 2 Cylinder project while I decide what grinder tool rest I am going to build. Boring the cylinder head, which is brass, is showing me that my hand grinding of cutting tools is not adequate. This requires a trip to a metal supplier and so need to fill up the hobby cash pile first.
In the meantime, I decided to revisit my previous CNC efforts. For the Unimat I used Mach3 (free edition) on a dedicated small PC. This worked well enough but it seemed overkill plus the learning curve for Mach3 is steep. After a bunch of browsing I came across Grbl and SmoothieBoard. SmoothieBoard requires a processor that I don’t have (it is partly based on Grbl though). For Grbl I only need an Arduino Uno, which I already have. It took some investigating to see if the 2.5D milling/routing that we want to do is supported by the limited G Code subset of Grbl. There are enough free tools to generate the code we need. Even helical threading is possible!
Now that I have 2 cylinders, it is time to make the pistons. These are supposed be graphite, which is easily obtained. But that only works if the cylinders are perfectly round inside. And regular borosilicate glass isn’t perfectly round. Close but not close enough. Option B is to make pistons out of brass and add a groove for an o-ring.
I’m a big fan of Plan B anything. First up, cut some hex brass to just over the final length of 2 pistons plus room for finishing the ends and the .05 wide cutoff blade. My 4×6 band-saw takes no time at all. Some time spent aligning its blade means that cuts are close to perpendicular. Less post processing that way. At same time I also cut the cylinder block. It amazes me sometimes just how much scrap material my dad collected from various places he worked. The waste was incredible. After 40 years I am still using the scrap leftovers.
Really, really almost done for now with my ‘must make’ tool list. My DW wanted to avoid looking at dark brass marks on my fingers at dinner. Since I will be turning knobs a lot while making my engine, it was time to retire the original brass handles on the carriage, cross slide and vertical milling slide. The handle design came from Keith Brooke’s excellent article on making zero-resettable dials for the Taig.
Making 1 of something is a simple task, making 3 identical units is something else. I marked out the dimensions on the first spindle, and then used that as a pattern for the other 3. Each was almost complete before moving on to the next one. The cross slide DRO was most useful. Touch the cutting tool to the material, zero the DRO, calculate diff between original and target diameter, divide diff by 2 and you get the desired reading for the DRO. (It always measures radius, not diameter). Wind the cross slide to the desired number, press zero again and now all you need to do is cut until you get to zero!
Nearing the end of the Must-Do list prior to starting the Jan Ridders engine.
Several years ago I bought a lovely 30mm boring head from Chronos in the UK. I had adapted it to the Unimat and kept it after that lathe was sold. For the engine I need to counter bore various holes to seat bearings, a perfect job for the boring head.
Lee Valley supplied the blank arbor, I bought 3 this time and milled the tightening flats on all 3 to save that setup when I need to make a custom tool.
A bit of turning, tapping with the die holder, polish up with emery cloth and oil to end up with a shiny new arbor. The thread is M10x1.5 .
The overhang is as short as I can make it. The 6mm boring bars will need to be razor sharp and small feeds to avoid flexing them. A test cut prior to making the arbor worked quite well. More practice aligning the cutting edge should result in excellent bores.