Gears

[Franco ConvertiniParticipant @francoconvertini28916]

I have several gears like the one shown in the photo. The only difference is that they have a 31.75 mm center bore. I believe they came from a Myford lathe, but I haven’t been able to figure out which model. Could you point me in the right direction?

Thanks, Franco

[bernard towersParticipant @bernardtowers37738]

OD and No of teeth would help

[duncan webster 1Participant @duncanwebster1]

If they have 1.25″ (31.75mm) centre they won’t fit a Myford

[bernard towers]

On bernard towers Said:

OD and No of teeth would help

The teeth have the same pitch as the MyFord Super 7.

[DC31kParticipant @dc31k]

A gear with a plain bore has limited use unless it only has to rotate on the shaft on which it is mounted.

Does the 1 1/4″ bore look OEM or could they be Myford items that have been modified?

What is the tooth count of the selection you have? Your answer above is incomplete.

If they are the same specification as Myford ones, they could be bushed down to fit a Myford, so the comment above about “won’t fit” is only partially true.

[Nigel Graham 2Participant @nigelgraham2]

Change-wheels always carry the tooth-count, as that does, but often also the lathe-maker’s name.

They may have been used on a Myford lathe, somehow, but I am afraid “believe they came from a Myford lathe” is not proof they are proper Myford fittings.

The bore is too large for a start, but even if the DP, a standard value, is correct for Myford the pressure-angle might be wrong so mixing them with correct ones will damage one, or both, of each meshed pair.

[Nigel Graham 2]

On Nigel Graham 2 Said:

Change-wheels always carry the tooth-count, as that does, but often also the lathe-maker’s name.

Could you quantify the “often” in that statement.

If we picked change gears from five different manufacturers*, how many would carry the name?

Alternatively, please state a manufacturer that you know for a fact puts their name on their gears.

I am also slightly concerned about the ‘always’ in your statement. It only needs one unstamped gear to disprove it.

* Myford, Raglan, Colchester, Boxford, Harrison for example. How many Chinese mini lathe variants are there? Does even one of them apply their name to the gears?

[JasonBModerator @jasonb]

Out of interest what are the bores of a Myford Bull gear and the first driver on the left hand end of the spindle? Could these have been used for indexing the spindle?

[Nigel Graham 2Participant @nigelgraham2]

DC31k – I take you point about makers’ name: yes, that might not be universal practice, and more likely it would be abbreviated; but all change-wheels I have seen carry the tooth numbers. Otherwise they’d be a right pain to use.

My Harrison’s change-wheels are not embossed with “Harrison”, but with the lathe model – L5 – and teeth number.

 

[duncan webster 1Participant @duncanwebster1]

I think the bull wheel on an ml7 is some odd number like 65t, but S7 is a much more useful  60t. Geo Thomas did a worm gear attachment to engage with bull wheel can’t image it was easy to do the maths on a 65:1 reduction

[peak4Participant @peak4]

We’ve no seen a photo of the gears in question, the one in this thread has been lifted from some Myford site.
Some lathe change-wheels do have plain bores, and are keyed together with a pin.

Bill

[bernard towersParticipant @bernardtowers37738]

I think the pin versions are ML 3/4, I have put keyways in them in the past as they seem to be cheaper.

[Howard LewisParticipant @howardlewis46836]

Myford changewheels are Imperial, 5/8″ bore (15.95mm) and 20 DP, so a 100T gear would be 5.1″ OD (129.54 mm)

Wheels for 7 Series Myfords have a keyway, so that they can be compounded.

Wheels for ML 1,2,3 or 4 are dimensionally the same, but do not have a key way, using a 3/32″ pin to compound the gears or to a driving collar.

Since the gear shown has an oversize bore for a Myford, but if it meshes satisfactorily with  Myford gears, this one will be 20 DP, but intended for a different machine.

Howard

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