Clunky sound on lathe

[Tiger]

I've got the MC900 type lathe from Hare and Forbes and there is a clunky sound when I come down in speed. So, what happens is that the lathe runs fine at all speeds particularly the high speeds and then when I reduce the speed down to 800 or less there is a rattling sound. Belt looks ok, pulleys look ok and I have lubed the machine. I have not changed bearings but would faulty bearings work well at speeds above 800 rpm. If it is bearings, what bearings should I buy and what size, manual that came with machine lacks that information?

[Oldgreybeard]

I had a similar problem on my Tecknatool last month. I eventually found the problem to be a loose grub screw which 'locked' the thread insert in the scroll chuck which allowed the chuck to rock backwards and forwards when the spindle was locked. Tightening the insert and grub screw eliminated the clicking sound.

May not be your problem, but my approach was to work from the motor thought the drive chain checking each piece individually for any movement or end play. Just my luck, the chuck was the last piece in the chain. On the positive side, everything was checked, adjusted and oiled / greased.

Good luck
Bob

[chuck1]

Do the pulleys have grub screws and or a keyway? Disconnect power and turn shaft by hand to see if it clunks? Or with the lathe running use a parting tool like a stethoscope on the headstock (only the castiron) to pin point the noise.before you spent cash on bearings

[Tiger]

Thanks guys for your thoughts. Pulleys are connected via keyway and grub screws. All seems in order there, I did give the spindle pulleys a good clean as well as the pinion gear that the speed lever rotates. Everything seems a bit freer now however after taking the speed lever controller off I can't get it to engage with the spindle pulley properly, I'm only able to get the speed changing lever to engage 5 speeds rather than the 10 are available plus because of the restricted speeds I can't get the belt on, any suggestions?????

[chuck1]

Not without being there to actually tinker with it! Sorry!

[chambezio]

In regards of your bearings....like all types of machines you just can't go and buy bearings to suit "My Lathe" The way to do it is actually pull the bearings out and read off the numbers on the side of the bearing. The numbers give the actual size bearing required. Just as a word of warning....don't buy cheap bearings. It pays to buy "good" bearings that will give you trouble free turning

[dabbler]

It might just be you have the handle in the wrong place. When I had issues with a loose speed selector handle on my carbatec mc1100a, I accidently shifted to handle to a different position before I replaced the missing grub screw. The range of speeds available was reduced. I just had to loosen the grub screw, reposition the handle then re-tighten. I had an idea this might happen so I wisely decided to test operations before adding a drop of CA on the grub screw thread.

My mc1100a only has 5 (6 ?) speeds not 10, and the handle is locked into each “speed” with the locking pin on the lever handle fitting into a corresponding hole. With the handle in the wrong place it simply won’t be able to move to each position. The selector adjusts the tension on one reeves pulley, allowing the belt to shift higher or lower on the V as the pulley halves open and close, effectively changing the pulley diameter hence the speed change. If range of movement is limited, change of pulley tension is limited and so speed range is limited.

I changed the belt sometime last year. With the pulleys in the right position and the pulley spring tension at the right amount, it went on surprisingly easily. I read several threads which had how-to info. Can’t recall which sorry.

[Treecycle]

This (http://www.woodworkforums.com/showthread.php?t=180883) one is a good one Dabbler

[dabbler]

This (http://www.woodworkforums.com/showthread.php?t=180883) one is a good one Dabbler

Well spotted.

[Tiger]

Bit of trial and error but got the speed lever to mesh with the pulley, feels a bit slower but that could be just me, anyway i always wanted a digital tachometer so good excuse to buy one. Lathe works better now after thorough clean, source of noise is one of the pulley keyway slots has slightly enlarged causing a slight wobble, bearings are fine. Pulleys are die cast aluminium so not sure what i can do to make it a better fit for the keyway, anyway lathe runs better, these lathes do need to be lubed regularly.