KeithAug

Michael - I hadn't looked for a while - so much to catch up on. Very interesting techniques and everything up to the usual extremely high standard.

I just spent a happy hour catching up. Really beautiful work - well done.

Just been enjoying catching up Mark. Lovely work as ever.

Moab / Mike Thank you very much for you kind comments.

Mark / Wefalck Thank you for your interest and observations. One of the reasons for building the mill was to get higher speeds than available from my larger mill. The recommended speed for machining brass is 90 to 210 meters per minute:- The maximum size of cutter I plan to run in the mill is 6mm. The pulley ratios give me 8000 rpm, 12000 rpm and 16000 rpm respectively. Calculating cutting speeds for 8000 and 16000 rpm gives the following results:- The cells highlighted in yellow are all within the recommended range. You can see that even at the higher speed I still don't achieve the recommended cutter speed for a 1mm diameter cutter. At the lower speed only the 4mm, 5mm and 6mm cutters come within the recommended range. Of course for hardwoods much higher speeds are recommended. I expect to use the mill almost entirely for soft metals and hardwoods. The bearing speed rating is important. I scavenged the bearings from an almost new (but dead) Triton router which ran up to speeds of 16000 rpm. Fortunately I am working within this speed range.

I made the drive pulleys out of aluminium. In the end the sizes were dictated by the stock that I had to hand (which was a bit on the small size for the larger pulley). The grooves are sized so that the belt binds on the side of the groove rather than the bottom as this improves power transmission. The wedge angle I used was 30 degrees. The 3 pulleys give 3 different speeds, the minimum speed being 8000 rpm - a 3 to 1 reduction from the 24000 rpm lower speed of the drive. The boss was drilled and tapped to take grub screws. These fit into dimples in the shafts. the belt was made from watchmakers lathe drive belt of 4mm diameter circular cross section. The belt comes in 3m lengths and the required size of belt is cut and the ends heat welded together. The pulleys were mounted and the belt was installed and tightened using the adjuster previously described. And that is it. I have run it and done a couple of cuts and it seems to work fine. I really need to get on with another ship build to test it in anger. In retrospect i decided I didn't need DRO.

I use the micrometer attachment on the Byrnes saw extensively, however I find three aspects of it a bit frustrating. Firstly and probably the most frustrating aspect is that I find I often want to accurately cut widths (or a series of parallel slots) greater than 1/2 inch. To do this I move the fence and micrometer in series of steps, this is time consuming and (unless carefully done) introduces errors. Secondly I sometimes need the full travel of the fence and have to remove the micrometer to achieve this. Removal and replacement can be a bit time consuming. Finally my eyes are not as good as they once were and I sometimes struggle to read the small 1/2" micrometer body. I would have put up with these minor annoyances had my brother in law not donated a 2" travel Mitutoyo micrometer body recovered from one of his engineering projects. I mounted this on a quick release clamp which attaches to the edge of the table. This gives me 2 inches of fence travel before I have to reset the micrometer to its second clamp position. the clamp is designed so that the second position is exactly 2 inches further out than the first position. This means I can get the 2" to 4" range by simply moving the clamp. Removal and replacement of the micrometer is now very quick and tool free. The larger micrometer body makes reading far easier.

Thank you for the feedback Aviaamator. The next job was to sort out the motor mounting. I had drilled and tapped holes in the side of the sliding plate. On to these I mounted a 2"x2"x1" aluminium block, drilled to take mounting bolts and the up stands on to which the motor mounting plate was to be attached. 2" up-stands are required to allow room for the belt drive arrangement. One is fixed while the other swings on a short arm. The next photo shows the up stands fitted. The motor mounting plate clamps onto the neck of the rotozip body. The mounting hole was accurately bored and then split on one side using a slitting saw. A hole drilled at right angles to the slit takes the clamping bolt which pulls the mounting plate tight against the rotozip body. The up-stand on the swinging arm locates in the circumferential slot on the motor mounting plate. This allows the motor plate to be rotated to accommodate different drive belt ratios (different drive belt centre distances). The motor was then mounted.

The column of the mill needed to be connected to the X,Y table. This was easily achieved by using 2 pieces of mild steel - 1" x 1/2" section which was drilled and tapped to match the holes in the table and column. I had previously made the vertical carriage clamp ( see earlier ). I felt however that I could increase the stiffness of the column by clamping the head directly to the frame of the column. The original clamp was thus dispensed with and the alternative design was manufactured. The revised clamp was made from 2" x 1" section aluminium. The semi-circular groove is necessary to clear the rods on which the head runs. The back plate of the column was slotted to take the clamping lever. The clamping lever was modified from the one made for the discarded clamp. The assembled clamp can be seen in the following photo.

After an extended break I thought I'd better get back to finishing this thread. You may recall that I had been struggling with the shaft recovered from a Triton router. Having binned it I made a more substantial shaft by turning down a mild steel bar between centres. The bearings locate against the shoulders on the shaft and are fitted from either end. The brass ring in the picture is a spacer which allows the distance between the bearings to be finely tuned to match the spacing of the bearings in the head. A very good fit is required to eliminate any axial movement of the spindle during milling. The following photo shows the assembly with the spacer in place. Having thrown away the router spindle I also chose to dump the router chuck (it was a little big anyway). I bought a cheap ER11 chuck off eBay and turned down a spigot on the shaft to take this. The shaft was then mounted in the head and the bearings were secured using the 2 previously made retaining plates. I did the eccentricity check again and recorded minimal run out. Amazing how doing something the right way seems to give better results.

Richard / Moab Thank you both for visiting. I have been otherwise occupied for about 6 months, but i did manage to finish the mill in that time - I'll post the results as soon as I get a few minutes - hopefully later in the week. In the mean time I will also be sorting out the next model which I hope will be underway before Christmas. Keith

good looking sails - very nice.

One step forward and two steps back seems to have been the motto for the last few days. One off builds tend to be that way and fixing / improving the design on the run is a necessary part of the process. I continued work on the carriage clamp and pressed into service my ball turning attachment that I made several years ago. I needed a ball for the end of the clamp handle. The funny thing about ball turning attachments is that they are always high on the must have list but are seldom used. In a little over 4 years this was its 4th outing. I do find the process quite satisfying. The clamp worked well, and with a bit of polishing the ball looked just the job. Unfortunately I subsequently decided I needed to stiffen up the slide assembly and the design for doing this involved a different clamping arrangement - so this work was wasted. I then measured the run to on the spindle and it was a deal greater than I thought necessary - about .003" eccentricity. So followed a day tracking down the problem. On inspecting the collet i realised the bore was rough and did not run true when measured with the dial indicator. I decided to re machine the internal taper. I set the topside to the correct taper angle using one of the collets as a reference for the dial indicator. I then machined the taper angle in the collet bore. I then rechecked and found that the eccentricity had only improved marginally. I continued to check and even checked the bearings were running true - they were!!! Having eliminated all other possible causes I was forced to conclude that the bearing seats on the shaft were at fault - you may recall from earlier I had re machined one. If I had started from scratch I would have turned the shaft between centres, but I took a short cut. The shaft is now in the bin and I have dug out a bar from which to make a new one by the correct method!!!!!! So in summary most of the work over the last few days (like the shaft) is in the bin.

Patrick, they don’t make them like they used to. Can’t wait to see what you imagine to be inside. Perhaps warp engines with dilithium fuel bunkers.

John, I was pleased to see the update. The final version of the sail looked great and the use of shell was fascinating. Your self control during the fan incident demonstrates excellent marital skills but you might consider buying her flowers, as a thank you, and to encourage her to do it again.

Mark - I'll be interested to how you get on with copper.

M Mark, lard is animal fat Lard oil is the clear, colourless oil pressed from pure lard after it has been crystallized, or grained, at 7° C (45° F). It is used as a lubricant, in cutting oils, and in soap manufacture. ... Lard oil has excellent lubricating qualities, but it tends to become rancid

Thank you Mark. Today the temperature outside was 25 deg c (77 deg f). If felt hot but fortunately the workshop only got to a comfortable 16 deg c. I reached a bit of a milestone in the build. I made the carriage lock for the sliding plate and attached it to the plate with 2 bolts (the 2 smaller holes). The locking handle has still to be made and uses the larger centre hole. With the lock attached I was able to bolt the bearing housing to the sliding plate. I was then able to assemble the milling head on to the runners. The leadscrew and nut were then assembled. Finally I have something that starts to look like a mill. The head now moves smoothly and securely in response to the turning of the leadscrew - very satisfying. I took a couple of further shots to show maximum and minimum elevation.

Mark - copper can be quite tricky - it work hardens quite quickly and pick up on the tips of tools can give a poor finish. Because it is very soft it can also be prone to snatching at the tool. My advice would be to use HSS tools which are sharpened to good edge. My preference is to use cutting oil as i think it lessens the tendency for pick up and snatching - as a result gives a better finish. But here is what the experts say:-

Dave, the strips of wood with angled cuts look like they are the sides of stairs. The treads go in the slots.

Lovely day here - bright sunny and 24 deg centigrade, only 2 weeks ago I was walking in snow - thats British weather for you. More progress - the spindle is now done. The spindle as removed from the router had bearings at the extreme ends:- The spindle had been machined so that both bearings were press fits (and as a consequence took some getting off). I used the lathe tailstock as a press to replace the lower (chuck end) bearing The distance between bearings was circa 6 inch. I wanted the bearings on the mill spindle to be circa 3 inch apart so I needed to turn down the shaft. Easier said than done as the shaft turned out to be as tough as old boots. My preferred HSS tools struggled to cut it and I was forced to press my TCT tools into action. Even then it was a slow process requiring plenty of cutting fluid. Anyway some time later:- The outer races of the 2 bearings are clamped axially in the bearing block and the inner race of the lower (chuck end) bearing is rigidly clamped to the spindle. Consequently the newly machined seat for the upper bearing needed to be a sliding fit. The shoulder on the shaft is about .010 short to allow for the expansion of the spindle relative to the bearing housing. The spindle / bearings were then mounted in the housing and the chuck was replaced. The chuck is treaded such that the action of the cutter is to tighten it on to the spindle. The spindle shaft sticking out of the the top of the bearing housing will be used to mount drive pulleys - currently I think 3 pulleys. The spindle feels nicely tight with no unwanted movement. I next needed to make the carriage lock for the vertical slide. This will be bolted to the slide plate and will clamp round the right hand slider bar. Three more holes were drilled in the slider plate and the block for the clamp was cut from 2" x 1" bar. The final operation on the slide plate was to machine and tap holes in the upper left hand edge to take the mounting for the motor (yet to be designed). Fortunately I think that is the end of machining on the sliding plate, it is already looking a bit like a Swiss cheese. I also mounted the boss on the back of the slide plate that attaches to the leads crew nut. The leads screw nut is fastened in place by the grub screw in the end which via a taper pushes out the pin on outside diameter. this clamps the lead screw into the bore - see phot.

Druxey - thank you - and an interesting point you raise. In the UK periodic table its aluminium:- Is it aluminum in the Canadian table?

So here goes with a little more progress. The bearing houses stands off the sliding plate by 2 inches. A 2"x2"x1" piece of aluminium was cut from bar and the ends machined square. The bearing housing is drilled and tapped (M8) to take the bolts that will secure it and the stand off to the sliding plate. In the previous photo the bearing housing is held against the mill table by the black clamp while the side clamping is achieved through the bar with 5 horizontal cap bolts. I made this some time back and find it very useful. A recess is cut in the bearing housing to take the stand off. The set up means that the recess is parallel with the axis of the housing. The fit of the stand off into the housing has to be good to make sure that the housing axis is parallel with the stand off. The quality of the fit is illustrated in the next photo where the housing is suspended from the stand off by friction alone. A better view of the joint can be seen in the next photo. I needed bearing retaining plates for either end of the bearing housing, these were cut from 0.1" aluminium plate. The next step was to create the cut out and holes for attaching the stand off to the sliding plate. This was virtually a repeat of the operations to connect the stand off to the bearing housing. And once again I did the friction suspension test to demonstrate the fit. The next photo shows all 3 parts assembled and held together by friction. Thats it for the present. Tomorrow I am going to have a go at machining up the spindle and mounting it in the bearing housing.

Tecko I have always found that good quality wine corks are a great source of modelling material. It takes a while to accumulate a decent quantity and the collection process often makes me forget why I was collecting them in the first place. Model is looking like the bees knees.

Mark, looks a lot of fun, the sin off envy is raising its ugly head.