Eagle 25 Milling Machine
Eagle 25 Mill by Chester UK
At long last I've finally picked up a bigger milling machine! This was bought off Ebay at a very good price and is virtually unused. My brother and I travelled to Stockport to collect it and managed to get it in the Astra Estate by unbolting the column from the base and removing the head. It was still a struggle but worth it!
I've stripped it down completely and cleaned all the sand, grit, and swarf from the castings and holes and then rebuilt it. It's worth doing this to all these cheaper Chinese mills as the cleaning of the parts in the factory before assembly leaves a bit to be desired.
It came with the 4 inch machine vice and a collet set with metric collets. It's a metric machine (not that I'm bothered about that!) with an R8 spindle which I think is better than the MT3 spindle as it's easier to remove the R8 tooling. Unfortunately, the collet chuck and collets are a non-standard spring type (Chinese brand). They are very similar to the normal ER collets but a different size and taper so it's not easy to get other collets to fit. It would be nice to get a set of imperial collets as well as the metric ones as most of my endmills etc. are imperial sizes. The mill came without a drill chuck so I need to pick one of those up sometime, also a proper clamping set would be useful.
I can see changing the spindle speed will be a bit of a pain as this involves moving two belts and undoing a couple of bolts. I've got a spare 1HP, 3phase motor and I think I may eventually fit this along with an inverter to vary the speed. Much easier!
The machine is too big to go in the house workshop so at the moment it is outside the back door in the covered area that runs down the side of the house. Not ideal but it will have to do for now. I am also getting an old Denham Junior lathe from a friend at the club so that is going to have to be found a home as well shortly! I can see that I am going to have to eventually build a proper outside workshop!
The mill has been giving good service in it's new home in the new workshop but there are a few improvements that I want to make to it.
I have yet to fit an inverter drive and a three phase motor to make changing the spindle speed much easier. Having to change two belts has proved to be an absolute pain and it's very awkward to do. Consequently, I tend not to change speed at all if possible. I have picked up a faulty 3HP inverter off Ebay that I'm hoping to repair and fit along with the new three phase motor at some point.
The second improvement has been on the cards for some time and that is to fit a two axis DRO to the table. As mentioned above, the machine is metric but I do most of my work in imperial so I have to convert everything. That's not a problem really but can lead to mistakes being made. The DRO will solve that problem as it can be switched between the two systems. It will also be far more accurate than relying on turning dials which can also lead to mistakes!
I already have a digital readout for the quill feed. I bought it at one of the model engineering exhibitions a few years back but never got around to fitting it. I decided to bite the bullet a couple of weeks back and buy a two axis DRO kit and use the scale that I already had for the Z axis..
I went for a chinese 'cheapy' direct from China ( advertised on Ebay ) as they are so much cheaper than the ones sold in the UK, most, if not all, of which are no doubt made in China anyway. I didn't go for the cheapest ones but a set made by Sinpo which seem to have quite a good reputation. This came with glass scales with 0.005mm resolution. The actual accuracy will be less than that but far better than I can achieve with the dials. I measured the actual travel of the table in X and Y and added a bit to get the working length of the two scales. I ordered a 150mm travel for the Y axis and a 400mm for the X axis.
The kit took about two weeks to arrive and I had to pay £21 in VAT and other fees when it was delivered. Remember that if you order items with a reasonably high value from China etc. you will be liable to pay import duties and VAT when the item arrives. I think the sellers usually give the items a far lower value than they are actually worth to keep the extra payments as low as possible. You may find that the courier will also add a fee as they have to pay the duties on your behalf before they can collect them from the Customs and they charge you for this.
The DRO kit arrived this morning as two separate parcels and was well packed and everything was in good order. The kit consists of the display unit and mounting arm, the two scales, covers for the scales, and various brackets and nuts and bolts for mounting them. From what I have read, you usually have to modify these brackets or make your own to suit the particular milling machine. These kits are not a simple bolt on job! The kit also included a pressed steel plate for holding collets etc.
I connected up the scales to the display and switched it on and everything seems to work as it should. The only slight problem was that the mains lead had a continental type plug on it which is no use in the UK. I have plenty of suitable leads but I may just chop the plug off the lead that came with it and fit a proper UK 3 pin plug instead.
I haven't studied the manual yet but I gather that they can be hard to follow and understand as they are usually written in 'Chinglish'!
Well, yet another year has gone by! I ventured into the workshop today for the first time this year and did a bit of tidying up and cleaning. The boxes containg the DRO were still on a chair where I had put them in September so I thought maybe it was about time that I did something with it!
I've got one or two jobs to finish before I can spend the time installing the scales but I decided to at least mount the display and get that box out of the way.
The original idea was to mount the display on the right-hand side of the mill but there wasn't really enough room for it to go there. I therefore decided to fit it on the left-hand side by mounting the bracket on the back wall of the workshop. It will be less obtrusive there anyway and can be folded back against the wall when not in use. It was just a case of fastening the bracket to the wall with some wood screws and job done.
The mains lead that came with the DRO kit is much too long and also has the wrong style plug on it so that will be shortened and a proper UK 3 pin plug fitted.
The holder for the mill clamping set was originally on the back wall but I've moved that to the side wall on the right-hand side of the mill. It's easier to get at it there anyway. Those spanners will have to be moved as well!
I've spent some time looking at how to fit the X axis scale to the bed. Most people seem to fit them on the back of the bed but thaty would mean losing some of the Y axis travel which is a bit limited anyway. So I decided to fit the scale to the front of the bed instead. This also meant that mounting the scale and the reader head would be very simple as the scale could be mounted directly to the front of the bed using the existing Tee slot on the front and the reader could be mounted directly to the front of the Y axis casting. No brackets or any complicated fixings would be needed. This did mean that I would loose the travel stops that used the front Tee slot but I rarely used those anyway. The stops were a rubbish fit in the slots anyway and the slot itself varied in depth and width across the casting! With the DRO fitted I wouldn't really need the stops anyway as I can just use the DRO to stop the table where I want it.
I made a couple of custom Tee nuts to fit each end of the slot and used two of the included M5 bolts to mount the scale to the bed. The Y axis casting was slightly proud of the front of the bed so I had to fit some brass shims between the scale and the bed to make sure that the scale and the reader head were exactly in line. After the scale was mounted and the top set parallel with the top of the table, I used a transfer punch to mark the mounting holes for the reader head. These were then drilled and tapped for two M5 bolts.
The mounting holes in the reader head were tapped M5 as I presume you were meant to mount this onto one of the included brackets. I drilled out these holes to a good clearance fit for the mounting bolts so that the head could be adjusted slightly if necessary. I also reduced the diameter of the heads n the bolts for the same reason as they were recessed into the head.
When I was determining the position of the reader head I left the plastic transport strip in place between the reader and the scale. I then clamped the reader to the scale before marking the position of the mounting holes. That ensured that the reader was parallel to the scale. The transport strip was then removed once the head was bolted on.
Next job is the Y axis scale which will not be so simple unfortunately!
One thing I noticed was that I think there should have been a length of aluminium bar in the kit for mounting the X axis scale to but it was missing. The idea is that you mount the bar to the mill and then bolt the scale to the bar. There is one for the Y axis though. As it happens, I didn't need it for the X axis so no problem.
Also, the cables for the scales are way too long. I could mount the display down the other end of the shop! I suppose the manufacturers have to allow for every possibility when the kits are fitted. I could shorten the cables quite easily if necessary but I'll probably do what everyone else seems to do and just coil up the excess.
To be continued
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