Author Topic: Cam Follwer Re- Radius for Machinist to Use Pse?  (Read 510 times)

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Hi folks..what's the radius on the A7ss cam followers? Some say they are flat bout others say there is a very big (= very small in effect) radius.

I need a figure to give my machinist/grinder to reface my followers. They are not bad, but two have  slight ridges and are NOT from my engine.

Cheers

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 6183
  • Karma: 35
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #1 on: 13.06. 2018 19:43 »
I have the cam followers out of my A10 at the moment. Would they be the same as the A7 SS? I'll try to estimate a radius for you if no one else can give you a definite answer.

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #2 on: 13.06. 2018 22:59 »
Hi Greybeard...it's hard to get an answer. Someone told me a while ago that it's a huge radius, almost imperceptible at something like 2 inches?????

Offline Klaus

  • Valued Contributor
  • ****
  • Join Date: Jun 2015
  • Posts: 376
  • Karma: 10
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #3 on: 14.06. 2018 06:27 »
As I keep in mind the radius is 1.1/2 inch.
a bigger radius means a quicker lift and so the acceleration for all parts is imense and caused to smashed these.

cheers Klaus


If you think, everything is under control, you are not fast enought.

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 6183
  • Karma: 35
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #4 on: 14.06. 2018 09:05 »
a bigger radius means a quicker lift and so the acceleration for all parts is imense and caused to smashed these.
As I'm looking at a set of prematurely worn followers your post makes me wonder if the radii were wrong.

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 6183
  • Karma: 35
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #5 on: 14.06. 2018 10:14 »
I have the cam followers out of my A10 at the moment. Would they be the same as the A7 SS? I'll try to estimate a radius for you if no one else can give you a definite answer.
I just checked the parts list. Seems the A7SS followers are the same part number as the A10 Plunger. I'll see if I can come up with an estimate of the radius.

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 6183
  • Karma: 35
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #6 on: 14.06. 2018 11:19 »
These followers may not be accurate. I'll measure the new SRM ones I've ordered when they arrive. The radius of these seems to be 1 3/8", (35mm). I've aligned the unworn section of the surface with my arc.

Offline duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4540
  • Karma: 41
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #7 on: 14.06. 2018 11:58 »

 If it's any help, a few years ago when I was trying to determine a radius for something, I did a whole bunch of concentric circles in ~5mm increments (or smaller when I got closer to what I needed)- seemed to work easy
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 6183
  • Karma: 35
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #8 on: 14.06. 2018 12:17 »
The new SRM followers have arrived. They are closer to 1 1/4" radius.

Offline dave55

  • A's Best Friend
  • ***
  • Join Date: Oct 2016
  • Posts: 173
  • Karma: 1
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #9 on: 14.06. 2018 12:26 »
I would have thought a good machine shop would have a set of Radius gauges but if not R.S Components sell them for a tenner a set and they do internal and external radius .
BSA Bantam D7 175  1961
BSA A10 650 Golden Flash 1955 Plunger
Suzuki GSX1400 2003

Offline Sluggo

  • Serial Hoarder, or Eccentric Collector depending on viewpoint
  • Resident Legend
  • *****
  • Join Date: Jun 2017
  • Posts: 639
  • Karma: 11
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #10 on: 14.06. 2018 20:56 »
Most any machine shop WILL have gauges, but a smart shop asks the customer to spec what they want and annotate that on a work order.  If the owner has an issue its a simple matter of "We did the work to your specs".   A shop owner I worked with (We rented space in his facility, and he made parts for OUR operation)
had a favorite saying.. "I made it to print" but sometimes shop floor people would horde print copies and the problems occur when the floor guys are operating on Rev2 and you promised the customer Rev3.  My wifes machine shop deals with this daily.

Greybeard, thank you for illustrating that discussion with your pictures.  I have gauges for some applications, but often have discussions with people on these types of cam followers and trying to illustrate what is meant usually gets a blank stare.   Sometimes (I do) we focus in on the details and overlook simple solutions.  Instead of trying to sort out the std radius and a "R" radius for a Triumph, a simple graph like yours is so much easier.  Dont know WHY it never occured to me to do the same,  *problem* But thanks for that.
Remember that any advice received on a free internet forum is generally worth about 1/2 of what you paid for it.
We overcharge every 3rd customer to pass the savings onto you.
You can have High Quality, Low price, and fast turnaround. Pick any 2, Never all 3 at the same time.

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
Re: Cam Follwer Re- Radius for Machinist to Use Pse?
« Reply #11 on: 18.06. 2018 16:41 »
Dear Greybeard, thank you so much. 1 1/4 is slightly more aggressive lift I believe, maybe for a more performance cam? I have no problem with 1 3/8 since that is a gentler radius. Should not be a prob?

Cheers for you kind help