Starting to use Proxxon MF70

[barryblundellParticipant @barryblundell]

Hello, apologies if I should be posting this question elsewhere on the forum. I’ve recently bought a second-hand Proxxon MF70 – the basic machine – and have a couple of questions in connection with using it for a current project. In brief, I need to accurately drill a number of holes with diameters 1.6mm, 1.7mm, and 1.8mm. These must be aligned accurately so that they lie at right angles to the surface.

Drills available from Proxxon (with a 3mm shank) appear to only be available in 0.5mm increments.

Is there a collet that I could obtain which will hold the drill sizes that I need to use? Alternatively, are drills available with the diameters mentioned above that have a shank that will fit the 3mm collet?

Just one other question – am I correct in assuming that the Proxxon machine cannot be adjusted in terms of accuracy? I am asking this because using a small set square (of good quality), there appears to be a misalignment in terms of the vertical and one of the horizontal axes (there is no discernible play).

[John HaineParticipant @johnhaine32865]

I think you can get a Jacobs type chuck as an accessory which screws on instead of the collet closer nut. What is the misalignment you see exactly?

[JasonBModerator @jasonb]

Your mill should have come with a range of collets the largest will accept 1/8″ shank tools so provided you are not drilling very deep holes then “PCB Drills” will do the job. These have 1/8″ shanks and are available in many sizes.

[Michael GilliganParticipant @michaelgilligan61133]

The widely available carbide ‘PCB’ drills have a common shank-diameter

MichaelG.

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Edit: _ Jason got there first

[Adrian R2Participant @adrianr2]

Rather than worry about the machine alignment I would clamp something of similar dimensions and material to the workpiece to your table, drill some test holes and measure the result. If the holes are not vertical enough for the intended use then shim the test piece to compensate for the error and repeat. When you are happy replace the test piece with the actual workpiece.

 

[Michael GilliganParticipant @michaelgilligan61133]

I wonder if anyone supplies an actual 3.175mm collet in the MICROMOT style ?

https://www.proxxon.com/en/micromot/28940.php

MichaelG.

[Michael Gilligan]

On Michael Gilligan Said:

I wonder if anyone supplies an actual 3.175mm collet in the MICROMOT style ?

https://www.proxxon.com/en/micromot/28940.php

MichaelG.

Just buy them from an American site, as soon as they cross the pond they become imperial with Rounded metric equivalents 🤣

https://www.proxxon.com/us/micromot/28940.php

[Michael GilliganParticipant @michaelgilligan61133]

Nice one, Jason !

… although I was actually being serious:

If the collets were as good as they claim, then 3.175 would only be nipped by the front edge of 3.200 and the PCB drill would rattle.

Watchmakers have understood this problem for generations.

MichaelG.

[Roger BParticipant @rogerb61624]

The Proxxon collets are double coned so they have a reasonable range.

PROXXON – Steel collet set

 

[jaCK HobsonParticipant @jackhobson50760]

I have the TBM 220 drill. The collets are bad and suffer the problem Michael describes.

I use proxxon 28122 chuck which is ‘ok’.

[Graham MeekParticipant @grahammeek88282]

Proxxon do not list a drill chuck for the MF70. I am fairly confident the spindle nose thread on the MF70 is M8 x 0.75P whereas the TBM 220 Drill is 3/8″x 24UNF.

As the Collets are double tapers they do tend to clamp parallel within reason. Bristol-Ericson use a similar principle, but with 3 tapers.  Draw-in collets do not do this as Michael has already pointed out.

Regards

Gray,

[Roger BParticipant @rogerb61624]

As Graham says the two machine spindles have different threads.

The drill will take a Rohm geared chuck as well as the collets. The drill also has a 4mm hole through the spindle to allow the drill chuck to be removed and replaced and to allow the collets to be properly tightened.

 

The mill has a smaller spindle and just takes the collets. Both the spindle and the collet nut have spanner flats to allow the collets to be properly tightened (important with double taper collets like for ER collets).

The collets have 0.4mm slots which will limit the clamping range.

As a trial I put a 3.2mm collet in my MF 70 and clamped a length of 3mm rod. This seemed to rotate without wobble.

 

 

[Roger B]

On Roger B Said:

[…]  As a trial I put a 3.2mm collet in my MF 70 and clamped a length of 3mm rod. This seemed to rotate without wobble.

 

 

Thanks for the notes, etc. Roger

I must admit I’m rather impressed that Proxxon can supply these versatile collets at such a low price!

MichaelG.

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Ref. https://www.modelshopleeds.co.uk/catalog/product_info.php?products_id=104545

[barryblundellParticipant @barryblundell]

Sincere thanks for all of these really helpful replies, which have given me a much better understanding, and I’ve now placed an order for a set of the Proxxon collets. In addition and as a backup I’ve also ordered a Proxxon chuck – which they indicate fits the MF70.

In terms of the alignment of my MF70 – I bought it secondhand and although it appears to be in good condition I suspect it may have had some hard usage. Consequently the suggestion of correcting the misalignment using shims when setting up the material seems a sensible approach.

This current project is far removed from my usual sort of projects concerning building flying models, but is using much of this experience. Quite by chance my wife and son who are both pianists were given a nineteenth century grand pianoforte. It’s an amazing piano – or perhaps I should said it used to be – the reality is that at some point the mechanism (action) was very badly damaged. Subsequently somebody has tried to repair it, but has completely failed and so this pianoforte was abandoned. I’ve been working on it for several months, the initial problem being to correctly determine the original sizes of the various components. This hasn’t been at all obvious since the person who previously attempted the repair work had changed so much and didn’t seem to appreciate the level of accuracy required.. On the other hand I’m truly in awe about the original design and the way in which this was implemented so accurately. It uses what’s call ‘A Viennese Action’, which is quite different from the modern piano. In case this is of interest to anybody here is a link to a short video I made this afternoon:

https://www.youtube.com/watch?v=JeJWYISDaSA

Again – my thanks for all the helpful messages.

[Michael GilliganParticipant @michaelgilligan61133]

Thank You for posting the video … ‘though unfortunately I am struggling with the audio track 🙁

MichaelG.

[Graham MeekParticipant @grahammeek88282]

Sorry Barry,

I had totally forgotten about the Micromot Drill Chuck, 28941, which of course will fit your machine.

Sadly old age does not come alone.

Regards

Gray,

[barryblundellParticipant @barryblundell]

Thanks Gray,

In fact the chuck arrived today and will be great for general use. Unfortunately I don’t think that it will work for my current project. Fitting a piece of 1/8 inch straight brass rod into the chuck I rotated the chuck by hand and had a set square against the rod. During a single rotation of the chuck the set square revealed a degree of wobble. I tried refitting the rod to the chuck several times but on each occasion the degree of wobble was the same. It’s certainly small and perhaps wouldn’t usually matter. In fairness, in the sales info Proxxon do make it clear that the chuck is not intended for precision work. Fortunately I’ve also ordered a set of collets, which should arrive on Monday..

Regards, Barry

[Graham MeekParticipant @grahammeek88282]

Hi Barry,

I have had no experience with this accessory, but as the chucks construction follows my Stanley Wheel brace drill I would not expect a high degree of accuracy.

I don’t know if you have a lathe, or not, but you could mount your desired drills in a separate shank. By turning the outside diameter and drilling for your desired drill size at one setting concentricity is guaranteed. The drill can be secured in the hole with Loctite or if you prefer soft solder.

I hope this helps,

Regards

Gray,

[John HaineParticipant @johnhaine32865]

I have seen two styles of chuck for the Proxxon.  One is as Gray describes.  The other (which I have) came with my Proxxon drill stand and is a proper “Jacobs” style with a chuck key and is pretty good.  Screws on the standard thread.

I have to say that I was very disappointed with both my Proxxon purchases. Style over substance I thought.

[Graham MeekParticipant @grahammeek88282]

Regrettably John there is a mis-match as regards the threads. I had my suspicions earlier in this post and Roger B confirmed it with some photographs above.

Regards

Gray,

[barryblundellParticipant @barryblundell]

Hi Gray,

Thanks for this good suggestion – but sadly I have no access to a lathe at the moment… However, I now have a set of the Proxxon collets and also followed up on the suggestion of getting some PCB drills. So this evening I was able to fit the first axel pin with the required accuracy. It’s also been possible to improve the accuracy problem that I mentioned in my first post, which related to the lateral accuracy of the Proxxon table relative to the drill bit. On removing the table I found some small particles of swarf between the runners.

Interestingly, in the case of the Proxxon chuck that I bought several days ago, and the Proxxon knurled threaded piece that is used to tighten the collets, the flats that allow a small spanner to be used for tightening are absent. So I’m assuming that in both cases Proxxon anticipate that they are simply tightened with the fingers. For my present activity which involves working with 5mm mahogany, this is fine. However, I would have thought that when working with metal finger tightening would not be sufficient. Perhaps Proxxon are anticipating the use of pliers…

[Roger BParticipant @rogerb61624]

The collet nut that came with my Proxxon hand tool does not have spanner flats and from time to time I have had to use pliers to undo it.

The collet nut that came with my MF70 has 10 mm spanner flats in the lower knurled section. The nut does not seem to be hardened so it should be fairly easy to file the flats. I guess that there are actually two part numbers, one for the standard nut and one for the milling nut.

 

 

[Michael GilliganParticipant @michaelgilligan61133]

As a passive observer in this discussion, I can only offer this ‘find’ for information.

There is an interesting ER 11 spindle conversion  shown on this page:

Proxxon MF70 Milling Machine

with a link to the supplier.

MichaelG.

[Roger BParticipant @rogerb61624]

There have been quite a lot of options offered for the MF70, the ER11 spindle, reduction gearing to reduce the spindle speed  and allow 6mm cutters, CNC conversions as well as the official Proxxon one:

Proxxon MF70 accessories – USOVO

PROXXON – MF 70/CNC-ready

I like my MF70 in it’s base form, I think a lot of these accessories are stretching a basic cheap machine too far.

[Michael GilliganParticipant @michaelgilligan61133]

I’m glad you like your MF70 in its base form, Roger

The World is a better place when people are happy

MichaelG.

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