Thread: A little gear help

I would refer to a group of gears as a cluster.
The gears themselves look like they have a stub profile.

Michael

As stated, I would refer to them as a straight cut cluster...
Matt

I may have this wrong, but are you saying the 3 different size gears all mesh with the one gear (unlikely in my mind)? Or do they all mesh with their own matching gear?
This is the way that the leblonds 4 speeds on the qcgb are done (well 3 of the 4 are) and 2 of the verniers speed selectors in both the spindle and feed boxes. I had thought it a pretty standard thing.
Cheers,
Ew

Ah....I think the sun just came up.....ignore what I just said. I take it the shifter in question has 5 positions, (the bottom gears slide) one at either end on the larger gears and 3 in the middle on the same sized gears?

Sorry guys I might not have been clear in what I was asking, Ewan is on to it.

Originally Posted by Ueee

I may have this wrong, but are you saying the 3 different size gears all mesh with the one gear (unlikely in my mind)? Or do they all mesh with their own matching gear?

Yes as per your edit, 5 positions, only 3 gears, the middle one meshs with three gears of different tooth count. To the best of my recollection I've got this far through life thinking that that just wasnt done(other than youtube funnys that while they work you dont see used often....well not in my line of work lol). Now I think I have my head around how it works, there is a lot of sliding at the tooth contact point(well at least on two of the three ratios), with three different tooth profiles.

Stuart

So the three central top gears are 3 different sizes? they don't look it in the pic but i don't have your superpowers......

I think Dave J's box is the same, he sent me the parts diagram of it when i was designing my QCGB, yep still on my roundtoit list....which i seem to have lost it will be on this puter somewhere.....

Aren't the three top gears the same size but mesh with different tooth counts that are hidden behind (or above) and the bottom gears do the sliding? I thought the middle gear on the bottom shaft meshed with the three above and the left outside gear will mesh with the leftmost gear and vica verca for the right hand gear. It looks like the gears on the upper shaft are intermediate, ie, not keyed to the shaft. Or am I an idiot???

Phil

Originally Posted by Ueee

So the three central top gears are 3 different sizes? they don't look it in the pic

Well no, thats the point
They are the same size*, they have to be or they wouldnt mesh with the other gear. They just have a different tooth count.
If you look at the teeth from left to right The tip of the tooth gets thinner while the base of the tooth gets wider**.


Stuart

*size in this case meaning diameter

**pretty sure the base is getting wider but that is just an eyeball measurment

thats wrong.......so 3 different pitches to mesh with an in between pitch. like you i never thought this would be done. I guess it doesn't have to transfer much power. like you say there must be some slip. I wonder what this does to you thread cutting. You would probably get a really minute "wave" in the pitch as you cut it.....Trust the Asians to come up with such "ingenuity" (i'm sure thats what they call it)

Hi Phil,

The shafts you can see behind are the selectors.
If we call the bottom shaft the input* shaft, with the "tripple gear" keyed but sliding.
The Five gears on the middle(intermediate) shaft are keyed and fixed to the shaft.
Just in the top of the picture are the gears of the output shaft which are(as they would pretty much have to be) exactly the same as the gears on the input shaft, keyed and sliding.

Stuart

*it may infact be the output

Originally Posted by Stustoys

Hi Phil,

The shafts you can see behind are the selectors.
If we call the bottom shaft the input* shaft, with the "tripple gear" keyed but sliding.
The Five gears on the middle(intermediate) shaft are keyed and fixed to the shaft.
Just in the top of the picture are the gears of the output shaft which are(as they would pretty much have to be) exactly the same as the gears on the input shaft, keyed and sliding.

Stuart

*it may infact be the output

Thanks Stuart, got it now

Phil

My goodness Stuart - this thread has bugged me for 2 nights. Like Ewan & Phil I expected the '5-gear shaft' to be the idler shaft between the output & input. Why can I see a cluster of 3 just showing in the top of the pic? To me, they look like a mirror of the bottom 3-cluster. In each case, the centre gear of the upper & lower cluster would engage one of the 3 centre gears of the centre shaft, whereas the 'outer' gears of the 3-cluster can only engage the 'outer' gears of the 5-cluster.

From the image provided, it looks to me as though the far left and 2nd gear from the right (5-cluster) are badly worn/damaged, but it's mate on the (lower) 3 cluster looks ok. It would be good to see the condition of the centre gear of the upper 3-cluster. From the 'rules' - gears can only mesh with other gears that have the same pitch. More pix please Stuart.

All of this reminds me of aptitude testing when I was a young appy. Now my brain is fully addled, I'm off to sleep.

Daryl

No looking at the picture until you've read the post

Daryl I wonder if you miseed my post https://www.woodworkforums.com/f65/li...5/#post1653028

The teeth arent worn, thats the difference in shape needed

If you've been struggling so far this isnt going to help. All three gears on the "triplicate gear" have 18 teeth. You may look at the picture now, though I'm sure you wont believe me

Stuart

p.s. I have been unable to dig up any other pictures, infact I cant even find the original of the one above, strange as I have a rough date of when I had the QCGB off counting teeth to let me cut a BA thread.