Thread: X2 Mill Belt Drive

The other day I came across a spare drive belt for a Scheppach thicknesser, Poly-V 140J3, 14" long and 7mm width, just the right size to use to setup a belt drive for my X2 mill.
Some pictures attached showing drive and driven pulleys so far (keyway cutting still required), the poly-V belt, sketch of the pulley groove profile, spreadsheet printout that I set up for this application to determine the pulley sizes required for different speed ranges while minimizing centre distance variation, and the form tool for cutting the pulley grooves.

More to come.....

Andrew
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Looking good Andrew, that will quieten it down.

Look forward to your up dates

Dave

Some updates for post #715.
I chased up single lump of aluminium for $20 and decided to make the whole motor mount and
casing from the single piece.
After much work on the mill, including a few planning/dimensional mistakes and lots of
swarf, the motor/drive mounting plate is nearly complete.
Pictures include the spring return spindle lock, and the adjustable belt tensioning idler
pulley that avoids having to have movable motor mountings.
I have left the rear of the plate solid to allow for future mounting of a gas mill head
support system, and also to allow the plate to be attached to the top of the rear dovetail
casting for rigidity to prevent the spindle support casting from moving against the dovetail
casting (these parts are bolted together face to face, with no positive or repeatable
locating method).
The tensioner roller is supported by a pair of ball bearings from some old hard drives
(10,000 RPM).
The spindle lock spring was wound by hand using the lathe and an arbor to obtain the correct
relaxed diameter.
Just about ready for assembly and testing.

Andrew
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Hi Andrew,

Nice work. looks very slick Does that design still allow for speed changes using the pulleys with the different diameter?

Regards
Ray

Ray,

The pulleys that have been made are 2 speed and sized to give nearly the same centre distance at both low speed and high speed, and the adjustable tensioner has been positioned to work with both speeds.
The bearings on the tensioner roller will be working at approximately the same speed as their original use in the hard drives when the motor is at full speed and the belt is on the high speed pulleys.

The main unknown is how the bearings cope at that speed with the extra radial load of the belt tension, although I don't foresee having any operation on the mill that will have the spindle turning at 3000 RPM .


Andrew

Hi Andrew,
Thats a nice bit of work! You may want to be up round the 3k mark if you plan on milling ally a lot, especially with smaller cutters.

I worked on a Mueller inspired (ok i copied it) Dovetail measuring jig today. Just need to make the holder and 2 legs to support the business end.
The beam is 40x5mm. I have had to borrow the thumb screws from the Mars as of course i don't have a lathe working to make them

Don't look too hard. The machining on the stop is shocking....i think i stuffed up in every way possible today. I think i will try take 2 at some stage....

Edit, yes Stu, i hit the submit button before i had uploaded the pics just one more way i have stuffed up today!

Finally.....the drive is finished, assembled and tested.

Sweet...

Good Things:

It's very quiet compared to the original gear drive
Smooth, also
Better speed range in low speed (up to 1500), so I won't have much occasion to change the belt across to the high speed pulleys.
It doesn't look to bad (if I say so myself)
The spring loaded spindle lock works well for me (right-hand is available for using tools), and it also has 3 locking positions instead of the original one position.

Shortcomings:

The belt is very close fitting in the housing and accessibility is nearly zero at the motor pulley end...I dread having to swap to high speed if needed.
The belt tensioner is nearly at it's travel limit, but I may get away with a longer screw if necessary. OK at the moment.

Future Improvements:

I may redo the motor mounting with a removable eccentric circular plate for belt accessibilty and coarse belt adjustment. The internal belt adjuster will still be used for fine adjustment and to account for belt stretch.
Fitting of a gas suspension system may be a good time for this improvement to be done.
Front top cover plate to be fitted for safety.

Pictures attached.

Andrew
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Looks good Andrew, great work.
It's hard to see problems before you finish and test it. Some times I spend many hours designing things so I don't have problems latter on, but I get caught out and have to redo things.
It's all a part of learning.

Dave