Make your own belts - UK Vintage Radio Repair and Restoration Discussion Forum

Studio263 · 5th Dec 2007, 11:06 pm

If you do a lot of work with tape recorders you will find that belts are a constant nuisance. No matter how many you buy there never seem to be enough and if you buy the "mixed" packs there are only ever a few of the useful sizes.

The answer is to make your own. The material to use is "o-ring cord", you can buy this from o-ring suppliers (look it up on the internet). They will offer you a wide choice of materials, "nitrile" is the one to go for as it is the most similar to what the original belts were made of. The other thing you have to specify is the cross-section diameter, 1mm amd 1.6mm are a good choice for cassette machines, with perhaps 2 or 2.5mm for open reel recorders and VTRs. Be a big-shot and buy a decent length (10 metres or so), remember that this sort of business is used to supplying industrial customers and so won't find it funny if you bother them for a 20cm piece! It's useful to have on hand anyway.

To make a belt out of the cord, simple slice the required length off the roll with a sharp craft knife. Make sure that the cut is clean and square, if it's not do it agin, it's worth spending some time to get this right. Gently roughen the ends with some oxide paper, 200 grit is about right. To bond the ends all you need is ordinary super glue. To work properly the glue has to be fresh (no matter how you store it it becomes pretty useless after about 3 months, so don't use that crushed up tube that's been in the bottom of your toolbox for years) and of a decent type, ignore those cards of 20 tubes that market stalls sell, get the real deal (Loctite etc, B&Q sell it).

Put a little spot of the glue on one of the cut ends of the cord. Then take the other end, ensuring that there are no twists in the rubber in between, and breathe on it. Super glue is activated by the moisture in the atmosphere and this accelerates the process. Now push the two ends firmly and squarely together and hold them there for about ten seconds. This takes practice to do properly so if the joint does not look straight or neat cut the bit with the glue on out and have another go. Don't try to pull the bond apart and do it again, super glue needs fresh, clean surfaces to work properly.

Once you are satisfied with the join, breathe on it again to cure off the remaining glue rapidly. Now leave the belt (as it now is!) for a few minutes for the glue to work. After this, give it a gentle tug to ensure that the bond is strong. If it passes this test, use your 200 grit paper to clean the excess glue away from round the bond. Be careful not to thin the rubber too much while doing this as it will cause a speed jerk in the recorder.

You can now fit the new belt and try it out. You may like to dress the surface with the grit paper while it is rotating to make the rubber a bit grippier and to smooth any surface imperfections. Hold a little piece of the grit paper onto the inner surface of the rotating belt to achieve this finish. I wipe over with IPA (head cleaner etc) afterwards will clean off all the little bits.

There you go, never be stuck for a belt again!

Mullard · 6th Dec 2007, 1:27 pm

This method works well. I have used it successfully on my jukebox for the turntable drive.
John

Tim · 6th Dec 2007, 5:16 pm

Yes, I have used this method on a couple of Grundig TK5's. In that case the advantage is a belt can be fitted without dismantling! Nitrile is ideal, as it won't perish and grips well.
Can't remember the company I used OTOMH, but they are happy to supply over the phone and cost is reasonable.

5th Dec 2007, 11:06 pm	#1
Studio263 Octode Join Date: Apr 2007 Location: Hampshire, UK. Posts: 1,578	Make your own belts If you do a lot of work with tape recorders you will find that belts are a constant nuisance. No matter how many you buy there never seem to be enough and if you buy the "mixed" packs there are only ever a few of the useful sizes. The answer is to make your own. The material to use is "o-ring cord", you can buy this from o-ring suppliers (look it up on the internet). They will offer you a wide choice of materials, "nitrile" is the one to go for as it is the most similar to what the original belts were made of. The other thing you have to specify is the cross-section diameter, 1mm amd 1.6mm are a good choice for cassette machines, with perhaps 2 or 2.5mm for open reel recorders and VTRs. Be a big-shot and buy a decent length (10 metres or so), remember that this sort of business is used to supplying industrial customers and so won't find it funny if you bother them for a 20cm piece! It's useful to have on hand anyway. To make a belt out of the cord, simple slice the required length off the roll with a sharp craft knife. Make sure that the cut is clean and square, if it's not do it agin, it's worth spending some time to get this right. Gently roughen the ends with some oxide paper, 200 grit is about right. To bond the ends all you need is ordinary super glue. To work properly the glue has to be fresh (no matter how you store it it becomes pretty useless after about 3 months, so don't use that crushed up tube that's been in the bottom of your toolbox for years) and of a decent type, ignore those cards of 20 tubes that market stalls sell, get the real deal (Loctite etc, B&Q sell it). Put a little spot of the glue on one of the cut ends of the cord. Then take the other end, ensuring that there are no twists in the rubber in between, and breathe on it. Super glue is activated by the moisture in the atmosphere and this accelerates the process. Now push the two ends firmly and squarely together and hold them there for about ten seconds. This takes practice to do properly so if the joint does not look straight or neat cut the bit with the glue on out and have another go. Don't try to pull the bond apart and do it again, super glue needs fresh, clean surfaces to work properly. Once you are satisfied with the join, breathe on it again to cure off the remaining glue rapidly. Now leave the belt (as it now is!) for a few minutes for the glue to work. After this, give it a gentle tug to ensure that the bond is strong. If it passes this test, use your 200 grit paper to clean the excess glue away from round the bond. Be careful not to thin the rubber too much while doing this as it will cause a speed jerk in the recorder. You can now fit the new belt and try it out. You may like to dress the surface with the grit paper while it is rotating to make the rubber a bit grippier and to smooth any surface imperfections. Hold a little piece of the grit paper onto the inner surface of the rotating belt to achieve this finish. I wipe over with IPA (head cleaner etc) afterwards will clean off all the little bits. There you go, never be stuck for a belt again!

6th Dec 2007, 1:27 pm	#2
Mullard Pentode Join Date: Jul 2007 Location: Clophill, Bedfordshire, UK. Posts: 127	Re: Make your own belts This method works well. I have used it successfully on my jukebox for the turntable drive. John

6th Dec 2007, 5:16 pm	#3
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: Make your own belts Yes, I have used this method on a couple of Grundig TK5's. In that case the advantage is a belt can be fitted without dismantling! Nitrile is ideal, as it won't perish and grips well. Can't remember the company I used OTOMH, but they are happy to supply over the phone and cost is reasonable. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."