Spur gears

[Howard LewisParticipant @howardlewis46836]

Any chance of a picture of the shaft, since you say it has both splines and a keyway?

If you measure the centre distance of the shafts, and the diameter, and tooth count of the driven gear, you should be able calculate the diameter and tooth count for the pinion that you seek.

The OD and tooth count of the driven gear will allow you to calculate the DP of the gears.

You already know the PA of the gears, so you will then have a spec for the gears, and the shaft details will allow a suitable gear to be found, or modified to suit.

Howard (aka Fat Fingers )

Edited By Howard Lewis on 27/03/2020 14:51:19

[Frank SloanParticipant @franksloan89570]

I dont know how to add a pic .

[Howard LewisParticipant @howardlewis46836]

If anyone is going to find a gear and produce a suitable internal spline / key way they must have dimensions.

At the moment we seem to be talking lengths of string., and no one can work like that.

Sorry but No dimensions = No gear!

Howard

[JasonBModerator @jasonb]

Frank did you read the link to the FAQ that that was posted earlier? If not click on the bold type here

[Frank SloanParticipant @franksloan89570]

Yes im trying to post pics and info i made an album so il see if i.can attached some.

[Frank SloanParticipant @franksloan89570]

Ive tried to upload the pics but cant get them in the thread please forgive my lack of tech knowhow.

[JasonBModerator @jasonb]

 

Bigger images in Frank's album

 

 

Edited By JasonB on 27/03/2020 16:07:20

[Frank SloanParticipant @franksloan89570]

[Frank SloanParticipant @franksloan89570]

So i managed to post a pic probably of no help but il try to get another i have up.

[Frank SloanParticipant @franksloan89570]

[JasonBModerator @jasonb]

Those are not splines on the shaft but the remains of integral gear teeth.

You said earlier 14.5PA but the two gears you show have 20PA on them?

The large 48T looks to be badly damaged so would need replacing along with a new shaft, problem is the integral teeth on the shaft are too close to the 1.25" nominal diameter to be cut with an involute cutter so will need doing on a gear shaper which is a specialist job

Edited By JasonB on 27/03/2020 16:23:17

[Frank SloanParticipant @franksloan89570]

I used the chart for the pa and i think 20 is closer.

[Frank SloanParticipant @franksloan89570]

Could the splines be cut then a collar pushed on and fixed in some way like pinned.

[not done it yetParticipant @notdoneityet]

JB,

It looks like it matters not whether the gears are cut into that shoulder on the shaft – it only acts as a spacer to the bearing, not a bearing surface.

Might the shaft clean up and accept a shrink fit gear?

Guessing the smaller diameter 8DP gear drives an identical gear on the other roller and both are undamaged?

I’m wondering what those other pieces of broken casting might be.

Back to you, the expert.🙂

Added:  That pinion gear is far wider than the 48 tooth gear.

Edited By not done it yet on 27/03/2020 16:59:08

[Frank SloanParticipant @franksloan89570]

This is something I was thinking but getting

These gears is my problem i dont know enough about this subject to know where to get them thats why i asked here and you are all really helpfull and thanks.

[Frank SloanParticipant @franksloan89570]

I far from an expert lol the casting is apart of the bearing housing i have someone who i think can

Repair that.

[JasonBModerator @jasonb]

NDIY, yes it may not matter if the larger diameter is partly cut into, without knowing the whole assembly it's hard to say.

Shrink fit gear may be very thing as it looks like from what remains is that the whole depth cut will be quite close to the shaft diameter. mat be possible to reduce shaft diameter so a more solid gear can be shrunk on along with a sleeve to bring it back upto diameter.

Frank, can you tell us how many teeth were on the shaft, looks like it may be 16-18?

[Frank SloanParticipant @franksloan89570]

15 i think but i will check for you.

[Frank SloanParticipant @franksloan89570]

Yes its 15 teeth.

[not done it yetParticipant @notdoneityet]

A guess -15 teeth – because the ‘spacer’ is likely 1 1/4” (extra confirmation it is imperial?)

Edit: Frank got back before me!

Edited By not done it yet on 27/03/2020 17:55:44

[JasonBModerator @jasonb]

Probably rules out shrink fit as 15T 12DP is 1.417" OD and with twice whole depth being 0.375" that would only leave about 28thou at the root.

[not done it yetParticipant @notdoneityet]

What drives the machine (to be clear that I am not referencing the gears, as in my previous post – for those that are unable to read, and understand, my specific wording&#128578. Power and speed reduction would be good as that pinion may need to be made of something more exotic than mild steel. Second thought is that a new shaft is likely the easier option.

[Frank SloanParticipant @franksloan89570]

[Frank SloanParticipant @franksloan89570]

Its a 1.5 hp motor.

[Frank SloanParticipant @franksloan89570]

Im sorry if i ask silly questions but im trying to understand new things to me making sence of this

Subject is a lot to take in i do appreciate your help and thanks to all who have responded to date .

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