Problems with T-nut Link Belt

[Taylon]

Hello to you all,

Has anyone used or had problems using T-Nut Link belting on Denford lathes?

Bought some recently and installed into my Denford Viceroy TDS/PCS, and I have traced a ticking noise down to the belt. Some of the bolt heads on the inner section of the belt are over sized and protruded over the edge of the belt material so contact the sides of the pulleys, resulting in a small groove being craved out of the intermediate aluminum drive pulley.

Anyone here experienced similar problems, if so how did you overcomes these issues?

Kindest regards, John R.

[Denford Admin]

The link from here has some good info on link belts... maybe a new one would be better?

viewtopic.php?f=50&t=2357

[paulmo101]

Hi John

Glad to see the majority of the rebuild going to plan.

I used the T link belt from tony at lathes.co.uk and its orange in colour - had no problems other than fitting the top belt was a pain and still possibly needs a link out.

I used to get a ticking sound now and again when using the old brammer belt but I found that by increasing the tension either on the top or bottom belt it seemed to clear it but as stated it seems Ok on the new stuff.

Keep us informed on the build.

Cheers

Paul

[Taylon]

Hello to you all,

Thanks to the members who have replied to this post. The ticking noise is down to the bolts used on this T-nut link type belting where the bolt head being to large a diameter and projecting beyond the the width of the lower section of belt material. The drive pulley has been damaged and a quantity of aluminum type turnings have been found on the belt and stuck to the grease inside the headstock form the damaged pulley that is now grooved.

Paul, I would check your drive pulley for damage. You may find that the pulley V has been enlarged.

Also I believe the belting bought is an inferior copy of the genuine T-Nut Link belting made by Fenner and other quality manufacturers. Now decided to ditch the T-Nut Link type belt and use a toothed continuous A section belt. The continuous belt length that has worked for me is 1171mm or a Goodyear AX44/AX45 belt.

I have found that it is just as easy to fit a continuous belt than than to mess around with this T-But Link/Brammer type belting. You just remove the nut from the head stock intermediate shaft and draw out the shaft and then remove the gears on this shaft from the headstock. Install the continuous belt and replace the gears and intermediate shaft. The pulley below adjustment bolts are fully wound up into the pulley trunnions and the pulleys slide across in one direction to disengage one of the slots in the pulley shaft and the headstock belt slide on to pulley shaft. Slide the pulley shaft back to engage with the adjustors and tension the belt accordingly. If that does not work just remove the trunnion nearest the tail-stock and install the belts that way, the bolts are under the bed in the base near the headstock and are exposed.

By the way, what do members consider to be correct tension on the drive belts, using the belt deflection method on the longest run?

Kindest regards, John R.

[paulmo101]

Hi John

Thanks for the heads up - I will have a look when I next get a spare 10 minutes.

Out of interest could you explain how you remove the trunions that tension the intermediate pulley? I installed my belt from the cover at the side of the headstock and by working from below in the motor bay but as I said it was a right pain as it was akward to fasten the T link while trying to maintain enough tension as the slack could be taken up on the adjusters - mine are already at full adjustment and I think I might have to remove a link in the future. The trunion Idea sounds easier than my method.

Cheers
Paul

[Taylon]

Hello Paul,

In answer to your request, there are 2 countersunk cap head bolts ( head size about 20mm) that screw down into each of the pulley trunnions from the base. One set of of these bolts is NOT accessible as these are covered by the headstock, the other pair are located just in front of the headstock on the base under/close to the bed. They are more than likely to be covered and gummed up with paint and muck. Hence you only remove the one trunnion that is closest to the tail-stock. To remove just undo those 2 trunnion bolts, you might have to use an tube on the Allen key to give you extra leverage. Once these bolts have been removed the trunnion can be slid off, but these are quite weighty so be prepared to support them.

Before you remove that trunnion make sure the pulley adjustors are fully wound up to slackened off the top belt so it can easily be removed and the motor belt is off the motor pulley.

Hope this helps.

Kindest regards, John R.

[paulmo101]

Big thanks for the info John - thats now on my jobs to do list.

Cheers

Paul