In need of a gear

[YYCHM]

It's the small 28T headstock drive gear depicted in this image. About all that I can tell you about it, is the following:

28 Teeth
Toothed portion is 0.385" wide (deep?).
The boss is 1.0" dia and stands 0.412" proud.
The shaft OD it mates to is 0.562"
The boss is drilled through to accept a shear pin that passes through the drive shaft and has a groove to accept a snap ring to capture the shear pin.

Willing to pay material and time (within reason) should you be able to manufacture such a thing for me.

I have the gear it mates to (which happens to be the same gear it's replacing) if that eliminates some guess work (i.e. the boss configuration, tooth profile etc).

Thanks,

Craig

 

[RobinHood]

Sent you a PM

 

[Tom Kitta]

You don't happen to have a PA for that gear - pressure angle? I may have a cutter for it - I think I have one for 28T and it is the M2 or M2.5. The cheap Chinese cutters are OK for mild steel but trying to cut a gear in 4330 was ultra painful. Cutting a gear takes longer then on a youtube for me but the killer is the setup.

 

[YYCHM]

I have the gear that the new gear needs to mesh with. Can we determine PA from that?

 

[Tom Kitta]

Yes you can determine pretty much everything by measuring the gear precisely - https://khkgears.net/new/gear_knowledge/abcs_of_gears-b/basic_gear_terminology_calculation.html

I also found that printing gear profiles and then comparing them with your gear work great as a test that you did everything correctly.

 

[YYCHM]

Ah, I see, great link. Pretty sure we are taking 14.5 PA here. It's an older machine.

 

[Tom Kitta]

I have few 14.5 cutters as well & can check.

 

[YYCHM]

While we are at it. Can anyone help me with the idler gear mounting bracket?

I have dxf files for it, if that helps.

Again, time and materials within reason.

Thanks,

Craig

 

[DPittman]

Speaking of gears...does anyone know of cheap supplier of gear tooth gauges?
A tooth gauge makes the identification of a gear pretty easy. They seem to be crazy expensive, considering a thread gauge that is of the same basic technology and material is so cheap. https://www.kbctools.ca/CatSearch/1396/gear-tooth-gages
I keep hoping that I will come across a used one that someone has no use for but that hasn't happened yet.

 

[RobinHood]

@DPittman , like this?

pm sent

 

[Tom Kitta]

Yeah tooth gauge is even easier then just printed paper profiles. But few people have these.

 

[YYCHM]

RobinHood had a look at my gear today (Thanks Rudy). Unfortunately he doesn't have a cutter for it.

The gear appears to be 28T, 18 DP, 14.5 PA.

 

[Johnwa]

If I remember correctly that’s what my Southbend change gears are.


Sent from my iPad using Tapatalk

 

[PeterT]

I hadn't realized that DP doesn't seem to be as common. The cutters are spendy new.

does this supplier have what you need or something you could adapt?
http://www.mymachineshop.net/category_s/55.htm?searching=Y&sort=13&cat=55&show=10&page=3

Ebay has some potential hits but lots of times listed under the lathe name as opposed to including the gear specs.

 

[Johnwa]

https://www.rdgtools.co.uk/ and jtsmach.com seem to have cutters. Not cheap though.

 

[YYCHM]

https://www.rdgtools.co.uk/ and jtsmach.com seem to have cutters. Not cheap though.

Hmmmm, I'm not finding 18DP gear cutters on the RDGTOOLS website?

The JTSMACH website lists some for $34 cdn (21 sterling did I convert that correctly?), but nothing for 28T.

 

[Johnwa]

RDG would be in sterling.
Try this link for JTS. they’re about $50 US.

RDG is pretty good at getting what you need if you contact them. it could take quite a while to get it though. I think they source from India.

you can also try grinding your own single point cutter.

 

[YYCHM]

Let's throw this out there for consideration.

RobinHood told me the gear doesn't need to be steel. Synthetic or Aluminum would suffice.

Dabbler tells me a brass gear that is close will wear in over time. RobinHood has a 16DP 28T cutter. Is that close enough?

John, you didn't provide a JTS link in your last post?

Craig

 

[Johnwa]

http://shop.jtsmach.com/Pr_CuttingTools/C025.asp

 

[PeterT]

RobinHood has a 16DP 28T cutter. Is that close enough?
Craig

No, a 16DP gear will not match up with an 18DP. They have to be the same.
What is the make & model of the lathe again?