Mini Mill belt drive conversion kit

Hello . I have recenctly bought a mini milling machine for hobby use . Ita Draper mill and is a chinese made and identical to most others on the market . Badge engineering at its best ! Reading up on it I now find that they suffer a common fault, namely the plastic gears break if overloaded ! A belt drive conversion kit is widely discussed on the various sites like youtube etc . All of these sites seem to be a few years old and adverts for the conversion kit that I have found are now long out of date . Does anyone know of any suppliers for these kits ?

Thanks in advance

Hi, Philip,

I converted my mill (Seig X2 type) to belt drive long ago, without using a kit. I recently upgraded it to use a 3-phase motor, with the same belt drive. I posted some pics of this conversion on this forum on which you can see the conversion, but it is not very clear.

It is a simple mod to do - basically remove the cast iron plate on the top of the mill - the drive gears are under this. I replaced this iron plate with a 6mm aluminium plate which carried the motor, and bought and modified two toothed pulleys to fit the head input shaft and the motor, and connected them with a short toothed belt. The motor mounting plate is remounted in place of the old cast iron plate using 6 aluminium spacers - this has been worked hard now for at least 15 years, and I haven't broken a drive belt yet. I made a new motor mounting plate because I needed to move the motor back a few millimetres to make the belt a good fit - there is room to do that. This mod also keeps the mechanical two-speed system on these lathes - some belts mods eliminate it. (and a 3-phase motor with VfD eliminates the need for it completely)

I'm sorry I am travelling away from home over Christmas/New Year, but if you are interested, I could run up a few sketches to make it clearer when I get back - the belt/pulleys were only a few Euros when I did it (20 Euro?), and a days work to make the ally plate and fit it.

Its a big improvement - most of the noise stops (caused by the gears), and the 'feel' of the mill is much better - more stable - I don't know how else I can describe it. Fitting the 3-phase motor (at a later date) was another good move - it is only a 1/2 HP motor, but is much smoother and more powerful than the old DC thing, and it removes the chance of unreliable controller board failure and 'death of motor' these mills suffer from. (spares are v. expensive!)

BTW - this mod is reversible - if you don't like it, or something go wrong, you still have the original parts to revert to standard.

Edited By An Other on 24/12/2021 11:57:36

I've had THIS ONE on my machine for many years. It works well and only takes a few minutes to fit. I'll remove the broken gears when I eventually convert to CNC.

I used to own an XJ12 mill, bought from Amadeal about 12+ years ago, but I don't know how that compares with your mini mill. I converted it to belt drive and was very happy with the result. Initially I thought I'd shortcut the process and bought the kit referred to above by Nicholas, from The Little Machine shop in the USA. At the time, I was living in France and even then the postal charges were eye-wateringly expensive. Even more so now, I'd guess.

Also, be aware that not all mini mills are built the same. I discovered this when my kit arrived, and to my horror, the spindle of my mill was a smaller diameter than the pulley in the kit. I ended up making a pulley to fit and cannibalised the rest of the parts to make a working conversion, Sadly no pictures. However, I do have a pdf of a similar conversion, should you wish to make your own, which I'll gladly email to you, if you PM me your email address. Below is lifted from that pdf to give you some idea of how it looks.

(The belt cover has been removed for clarity.) The pdf includes the drawings (in Imperial) of all the parts needed.

John

P.S. I think I've still got the original pulley from the kit and a suitable belt or two, somewhere, if you would like them.

Poly Vee conversion will give better performance than vee belts. This conversion was done ona X2 mill years ago with a 1.25 hp DC Motor added. along with other mods giving Trouble free running ever since.

I got my kit from Benchtop Precision but their website seems to have vanished and shown up again at Minipro (The installation manual is available for download). It was straightforward to do the conversion.

(Some discussion at CNC Zone).

Best thing since sliced bread!

Edited By Peter Greene on 24/12/2021 18:37:20

Thanks for all tha advice and offers of help. The kits look extremly expensive and only available from USA with all the added costs . I have bought a metal gear set for the moment . Noisy yesbut should be more durable than the standard plastic gears.

The annoying bit is that I have now seen a new mill for sale that has the belt drive and brushless motor fitted as standard and for similar price as I paid .

Thanks again

PF

FYI: The mini-mill group that used to exist on Yahoo was moved to groups.io and has all of the files (I think) including the DIY version of the belt drive conversion. Files are at https://groups.io/g/Mini-Mills/files/Mini-Mills

Requires a lathe, of course.

I did the exact same conversion as shown in JH post and from the same source.

It is not too difficult to do and has been very reliable and quiet ever since.

It was noisy as hell on the gears and as i was a true novice when starting with mine it did not take to long to get overambitious and frag the gears.

FWIW when i did mine I took the opportunity to change the bearing for taper rollers. Its exactly the same type and conversion as used on the mini lathe. I think it will be in the same group.io mentioned above , if not look at the ARC Eurotrade site for their article on the same.

It pays to do the bearing first so that you can triple check the dimensions and adapt the original design dimensions if required.

Good luck.

Clive

Hi Clive,

Not to change the direction of the thread, but do your tapered roller bearings require regular oil or grease?

Mike

I do not use the mill much. Its fits and starts as jobs require.

I made sure it was well greased at the beginning and have not needed to top up so far. All runs as smoothly as the day assembled 4 - 5 years ago.

Clive

Edited By Clive Farrar on 01/01/2022 12:24:27