Cam Grinder on The Go

[Brian-in-Oz]

Hi all,
After completion of the Forest Edwards Radial I decided to have a go at building a cam grinder with future engine (s) in mind other than a radial. Radial engine cams can be machined on a mill.
I am not far into the project and so far have almost competed a headstock that incorporates a fully indexable (through 360deg.) chuck.
In the near future I will post some photo's that will hopefully give a better idea of where I am at.
This will probably be a bit of a slow build as I currently have a few other things on the go but nowhere near as complex as the Edwards.

Cheers all - stay tuned :idea:

 

[michael-au]

Will follow with interest

Michael

 

[billscaramu]

This is a item I also would like to build. I will be following.

 

[ICEpeter]

Hello Brian-in-Oz,
I was wondering which system you intend to use in the cam grinder you plan to build. Is it based on a master cam / swing frame cam grinder? If so, there is an excellent thread on HMEM by Joachim Steinke documenting his cam grinder: http://www.homemodelenginemachinist.com/showthread.php?t=10361

I took the liberty and copied Achims concept and build my own cam grinder based on Achims work. See attached pictures. Have some dimensional drawings / sketches available if there is interest and am willing to post them. Unfortunately, they are not CAD but drawn in pencil but cover most aspects and details of my build.

Peter J.

 

[petertha]

IcePeter - yes, please! I for sure would like to read whatever you care to share. that looks like quite the machine. Just curious right off the bat, what kind of motor/grinding wheel rpm did you select? And is the X,Y positioning table re-purposed or also made? I'll save the other questions for your new post

 

[Hopper]

Beautiful work indeed. I too would be interested in any more info and drawings you can post. I am looking at making something slightly larger to grind cams for vintage motorbikes on and this look like exactly what I need.

 

[michael-au]

Hello Brian-in-Oz,
I was wondering which system you intend to use in the cam grinder you plan to build. Is it based on a master cam / swing frame cam grinder? If so, there is an excellent thread on HMEM by Joachim Steinke documenting his cam grinder: http://www.homemodelenginemachinist.com/showthread.php?t=10361

I took the liberty and copied Achims concept and build my own cam grinder based on Achims work. See attached pictures. Have some dimensional drawings / sketches available if there is interest and am willing to post them. Unfortunately, they are not CAD but drawn in pencil but cover most aspects and details of my build.

Peter J.

Hi PETER
Your cam grinder looks very good well made, I would be interested in seeing any draws you have, if you want to share them with others

Thank you
Michael

 

[michael-au]

I will also follow this cam log as well, can always learn things by seeing how other people do it

Michael

 

[Brian-in-Oz]

Peter that cam grinder is a thing of beauty and lovely workmanship and design.
I think it should be called the Quorn of cam grinders.
Thank you for the offer of some drawings but I am far enough into making some parts that I am more or less committed to the design I have in my head.
The headstock is completed apart from engraving degrees for the indexable chuck. Once that is complete I can assemble the parts and press the bearings home and and fix the headstock to the bed. The tailstock will be next.
I will take photo's before and after assembly.
The design I have in mind is a master cam with the grinder attached to a swing frame and 4 to 1 size reduction. My aim is to keep the design as simple as possible within design constraints but with close tolerance fit of all moving and sliding parts. I have built a tool post grinder so have a bit of experience with some aspects of the design but I am a bit of a slow worker as my trade was storekeeper not a toolmaker or fitter and turner but have learned a lot from making the Edwards Radial.

Promise some photo's soon - Cheers all - Brian scratch.gif

 

[ICEpeter]

Petertha,
My cam grinder comprises two separate components. One is the actual grinder which I build before the cam grinder and it is a support grinder intended for use on my Myford S7 big bore lathe. Originally, I planned to use the support grinder on the lathe to grind crankshafts for the model engines I am building. The support grinder uses dia. 5 inch wheels, either aluminum oxide or CBN wheels both with a dia. 1/2 inch spindle bore. The support grinder uses a Sherline spindle in combination with a Sherline speed adjustable DC motor. The maximum speed is 10,000 RPM which I never use. I run the aluminum oxide wheels at around 4.500 to 5,000 RPM max. and the CBN wheels at around 7,000 RPM. I took my chances with the Sherline motor not knowing what torque to expect but in actual use and considering the amount of grinding depth per pass (less than 1/2 thou) the motor does not slow noticeably in use. When I go for 1 thou depth at roughing the motor slows a bit but does not stop.

The X / Y cross table was purchased from ENCO as a damaged unit and re-worked considerably. Squared up the slide ways / milled slide ways parallel / added new gib strips / put new 2.0 MM pitch spindles in / new spindle nuts designed to be play adjustable / ball bearings for spindles / new housings for spindle bearings / new 200 division dials with 0.01 (1/2 thou) graduation.

Peter J.

 

[ICEpeter]

Brian-in-Oz,
Thank you for your kind comments. Will follow along your cam grinder build with interest.
Your remark being a bit of a slow worker struck a note with me. I am slow as well but still manage to plow ahead, slow though. Have worked on my engines now for about ten years and finally have only two more parts to make before final assembly. So there is now light at the end of the tunnel and I look forward to maybe another 6 month or so. Heaven knows whether I am right on that.

Peter J.

 

[ICEpeter]

Hello all,
It appears there is a bit of interest in the drawings and build of my cam grinder and, as promised, I will post the drawings and sketches / photos on HMEM in a separate thread. Don't want to hijack Brian-in-Oz's thread.

I am looking at about 45 pages of 8.5 X 11 inch pages plus pictures and may require 7 or 8 posts. Will get my stuff together ASAP and start posting. Alternatively, I would be willing to send the whole package in one shot by e-mail to anybody who would like to receive it that way, instead of downloading 8 posts from the HMEM website.

I now will leave this thread for Brian-in-Oz to continue.

Peter J.

 

[Brian-in-Oz]

Hi all - here are some photo's of where I am at.
First photo is of headstock parts. I have not yet pressed left hand ball race into place as I still have to make an indexing pointer to line up degrees on indexable chuck and some holes will be needed to be drilled and tapped on top of the headstock. The chuck mount is tapped in six places which allows full 360deg. indexing by shifting the mount bolts in the three slots in the boss engraved in degrees.
The chuck is a Sherline 4 jaw. I chose this instead of a three jaw as I can also use this chuck on my lathe for small precision work by mounting it on a 3MT adaptor I machined with a 16TPI 3/4" thread.
The next photo is temporarily mounted headstock on bed.
The bed the headstock mounts to via a tongue in the slot for alignment is a 40mm square aluminium extrusion used for building such things as CNC and 3D printer projects.
Hope you can follow - Cheers Brian :shrug:

 

[Charles Lamont]

I am in the middle of building a camshaft grinder. At present I don't have photos or a useable GA drawing but I will try to sort something out in a week or two.

Mine uses a 5 : 1 scale cam template. I found the most difficult aspect of the design was to ensure that wheel wear and dressing is accommodated in a way
that preserves the correct geometry.

The wheelhead moves along the base to the right position for each cam. The camshaft, template and the reduction motor drive for them are all mounted in a basically horizontal frame above the wheel with a toothed belt drive over three pulleys. The frame rocks up and down as the cam template rides over a shoe.

The cam drive shaft has a protractor for the relative cam angles. The template rides on a curved shoe with a radius 5 times that of the wheel. Cut is put on by lowering the shoe. Different templates can be used for inlet and exhaust.

The shoe is moved up and down with a wedge under it, and the wedge is moved in and out by a micrometer feed. The wedge slope is 1-in-5. This gives a 25:1 reduction between the wedge and the actual cam, and with a 40 tpi thread on the micrometer screw, a full turn of the knob puts on one thou depth of cut. So, with 20 divisions on the dial, one div takes a tenth off the cam diameter.

The pivot bar for the rocking frame can be lowered to accomodate wheel wear. If the centre height of the bar is the same as the the topmost point of the wheel the geometry is preserved. Strictly, the shoe curvature radius also needs to be reduced to compensate.

 

[Charles Lamont]

The chuck mount is tapped in six places which allows full 360deg. indexing by shifting the mount bolts in the three slots in the boss engraved in degrees.

I have done the exactly the same! Well, except that I have shorter slots and 12 holes.

 

[Hopper]

Brian, what is the that bed made from? Is it a standard aluminium extrusion of some sort?

 

[Brian-in-Oz]

Hi Hopper - yes it is a standard aluminium extrusion available in quite a few different forms and dimensions and usually sold to people building up CNC or 3D printer type projects. I purchased a 600mm length on Ebay Aust. for $13.20 from a seller in Melbourne. I am not sure of your location but guess it is either Aust. or the UK by your spelling of aluminium (not aluminum). The same seller also has hardened and ground steel shafting and linear bearings and an assortment of mounting fixtures all reasonably priced. I will probably be using a some ground shaft and linear bearings later in the cam grinder project.
Attached is a picture and dimensions. Hope this helps.

Cheers Brian

 

[Hopper]

Thanks Brian. Yes, I am in Cairns.

 

[Brian-in-Oz]

Hi all,
headstock is now finished with addition of indexing pointer and assembled.
Next job to design and machine tailstock.

Cheers Brian :

 

[Charles Lamont]

Here is an image of my camshaft grinder taken from Onshape. Enough of the assembly is shown to get the basic idea. It is about half built so far. I will probably add a facility to oscillate the cam over the width of the wheel.