Drive belt for small Chinese pedestal drill

[Andrew TinsleyParticipant @andrewtinsley63637]

I have one of the generic cheap Chinese pedestal drills  The drive belt is in good shape and I can still read the identifiers on it. Rather than wait for the belt to wear out and the identifiers becoming unreadable. I would rather get a spare belt now.

This is where it becomes interesting. The identifiers are K680, 0505 and 46. The 680 is the belt OD in mm. What the 0505 and 46 mean, I know not. The belt cross section is very odd, being 7.5mm width and 6.5mm deep. I cannot seem to find a replacement belt that fits these dimensions. As there must be many thousands of these pedestal drills around, the belt cannot surely be an odd ball. Maybe I am looking in the wrong places, although it does seem to be a non standard cross section.

Anyone know what this belt is and where can I get a spare?

Andrew.

 

[Howard LewisParticipant @howardlewis46836]

The nearest, listed in Kempe’s Engineers Year Book, 1982, is a SPZ given as 8.5 mm pitch width, 9.5 mm top width and 8.0 mm deep, or a Y section belt which would be 5.3mm pitch width, 6.5 mm top width and 4 mm nominal height.

Maybe the “0505” refer to the pitch width and the “46” to the nominal 4mm height?

HTH

Howard

[Martin BrookfieldParticipant @martinbrookfield82338]

It is a Chinese belt and the designation is simply K-680, there are plenty on eBay that are k-660 so it might be worth checking whether this would do.  (I remember I replaced mine with a longer one and found that the original was probably too short since it was hard to change speed!)

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Howard,

Yes I made the nearest thing to be an SPZ belt, but it is not the same dimensions as the K680. Martin, I have tried Ebay and no one does a K680 belt. It may well be useful to try Aliexpress or Temu. If, as you say, it is a Chinese spec, then I may have more luck there. Not sure about the payment system, but well worth a try. The K680 belt is just right for speed changing, neither too tight or too slack. Having said that, I have not checked if there is adjustment on the motor to get the right belt tension.

Thanks both for your suggestions,

Andrew.

 

[duncan webster 1Participant @duncanwebster1]

I’d ring simply bearings or belting on line. They know more about belts than is healthy

[Andrew TinsleyParticipant @andrewtinsley63637]

I looked on Temu and Aliexpress and no luck. I will try Duncan’s suggestion, these belts must exist!

Andrew.

[larry phelan 1Participant @larryphelan1]

Might be worth checking to see if you can move the motor to suit the belt. I had a somewhat similar problem when I decided to replace the belts on my drill. They were 40 years old, not damaged, but I thought it was time to retire them, TLC, and all that.

The existing belts were A24, so I bought two new Mitsubishi A24 belts, knowing that they would a straight swap. No such luck ! they were just that bit too long, even with the motor at its limit.

Not prepared to make another 20 mile round trip to change them, I simply made up a few spacers to pack out the motor. Rough and ready, like most of my efforts, but it worked. The point is that you cannot depend on what it says on the box or the belt, it seems to be more a question of who makes these things. In my case, it was simply a belt, but had it been something else marked with the same size, it could have been very different.

 

As they say, “Believe nothing you see and half what you hear”

[Andrew Tinsley]

On 29 May 2024 at 17:16 Andrew Tinsley Said:

The identifiers are K680, 0505 and 46. The 680 is the belt OD in mm. What the 0505 and 46 mean, I know not. The belt cross section is very odd, being 7.5mm width and 6.5mm deep.

 

The usual protocol with belts would be the 680 in K680 is the circumference of the belt at the pitch depth, not the diameter. Is that what you have?

There seem to be plenty of K660s about, which if they are in fact only 20mm shorter in the circumference rather than the diameter, would only need a matter of the motor moving 10mm closer to the pulley to make up the difference. Do-able?

There are also a few K690s on Aliexpress that could possibly work if you can move your motor the extra needed 5mm away from the pulley.

These guys list a K686, aka K27 (inches) for the US market. https://beltpalace.com/ksectionbelt.html

According to them, the K series V belts are a special for drill presses, a nominal 5/16″ or 8mm wide across the top.

The K680 seems a rare beast though. It might be worth checking you have not misread the 686 as 680?

 

[Andrew TinsleyParticipant @andrewtinsley63637]

No definitely a K680 belt. I have been out annealing copper for a friend most of this afternoon. I will take a look at the motor on the pedestal drill and see what movement is possible,

Thanks,

Andrew.

[Michael GilliganParticipant @michaelgilligan61133]

This won’t help much, Andrew … but at least it confirms the section:

https://uk.misumi-ec.com/vona2/detail/221005023050/

MichaelG.

[peak4Participant @peak4]

You could try the VB-8 range here, which whilst shallower are the cogged design and might even do a better job
https://simplybearings.co.uk/shop/Belts-V-Belts-VB-Classical-V-Belts-5-/-6-/-8mm-VB-Classical-V-Belts-8x5mm/c4601_4790_5053_5056/index.html?selection=8mm+Wide+V+Belt

Bill

[Andrew TinsleyParticipant @andrewtinsley63637]

Thanks Michael , as you say the belt cross sections I quoted are near enough to the ones you reference.

Bill I am sure the belts you refer to are near enough in cross section, but the outside diameters for the two nearest belts are approx 660mm and 700mm. The really bad news is that there is NO adjustment on the motor position, which is most surprising! In fact a modification to the mount, to provide adjustment, is not exactly a trivial job.

Andrew.

[Andrew Tinsley]

On Andrew Tinsley Said:

[…] The really bad news is that there is NO adjustment on the motor position, which is most surprising! In fact a modification to the mount, to provide adjustment, is not exactly a trivial job.

I haven’t seen the configuration, but … might it be practical to add a jockey-pulley [if that’s the right term] that applies pressure to the back of the belt ?

… an idea quite commonly used on the ‘serpentine’ belts in cars.

MichaelG.

[Andrew TinsleyParticipant @andrewtinsley63637]

Can I thank everyone for their input on this problem. I have decided to bite the bullet and modify the motor mount to give some belt adjustment. Then I can go with the K660 belt which is the one K series belt that is very common.

I am still surprised that there is no motor adjustment on this version of the common Chinese pedestal drill. But as I only paid £30 for it, at a closing down sale, a few years back, I can hardly complain!! In all other respects it has been an excellent drill, with only a very little play where it really matters. The only other snag is that the table bends down when you apply a bit of pressure from the drill. An old car jack solves that problem.

Thanks again everyone, it is much appreciated.

Andrew.

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