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Member postings for IanH

Here is a list of all the postings IanH has made in our forums. Click on a thread name to jump to the thread.

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Thread: Slotting Tool Design
22/06/2010 19:55:11
Hi,
 
Some few years ago I bought a slotting attachment to hang off the back of my Bridgeport. I  now find myself wanting to create some 3/16" and 1/4" keyways in 1" and 1 1/4" bore holes in EN24 and am astruggling a bit with the design of the tool/tool holder. The slotting head has a 0.625" socket for the tool holder to sit in. Can anyone provide a sketch of something that will work?
 
I am anticipating using 1/4" square HSS tool bits for the 1/4" keyway and had thought of clamping it horizontally in the bottom of the tool holder. My first attempt has not been rigid enough allowing the tool to dig in and jam everything up. I can't find any pictures of commercial designs so thought I would turn to the forum.
 
Thanks in anticipation
 
Ian 
Thread: Roller bearing cages - full size
17/04/2010 20:03:08
Another attempt at the photo....

17/04/2010 20:00:41
I think a final scheme is emerging. Moving up to a 40mm od crank pin and using a stock needle roller bearing get you up to 45mm od. If you then add in a hardened ring in the conrod eye you are looking at boring the conrod something like 0.15" over the iriginal dimension. At ths size the conrod is looking rather delicate and as this all started with a fork rod failure,,,,,

New conrods with a bigger "big end" would be required.
Plan B then is to go to a 35mm crank pin allowing me to use 42mm od needle roller bearings which can be accommodated by opening out the existing big end sleeve by only .030 on diameter. I am pretty sure the sleeve is hardened right through so this should be achievable. The od of the sleeve doesn't change so the original pattern conrods will do. If I stick with the bronze bush in the blade rod then it should be straighforward.
Ian  
11/04/2010 18:14:34
Thanks for all the information - I would love to see a sketch of the broach and die set up Ian is suggesting - any chance of this Ian?
I have sent a message to mgj to check out the woodruffe cutter proposal - I think we have different ideas of what a woodruffe cutter is although I suspect it is because the cage is relatively thick compared with its diameter rather than being a thin shell as he suggests.
At the Three Wheeler Opening run today concensus of opinion amongst the racing fraternity was to use an INA caged needle roller bearing running directly on the crank pin. The proposal for the crank pin is to go to a parallel pin with .004" interference and press it together in the hydraulic press - no tapers, no threads! I have to admit that this is tempting......
Question is whether the blade rod will be ok on its bronze bush or should this be sleeved and a crowded needle roller arrangement be put in place - it only rocks back and forth when all is said and done.
Ian
10/04/2010 11:03:43
Thanks very much for this John,
This was the idea I had in mind talking about a two piece cage but I wasn't thinking of leaving the washer floating.
Reducing the inertia by going into a lighter material might be an idea?
What did you do in terms of clearance between the cage and the crank pin and the cage and the big end sleeve for both the cage and the floating washer? I am thinking of "Tuning for Speed" where there is discussion about the cage wearing the pin away,
What clearance did you use between each roller and its slot? I am thinking that using shaped slots like this you could keep the cage off the pin and sleeve, but the washer would be free to run on the crank pin.
What do you think of giving the washer a register to held it in position on the cage - the register would need to be deeper than the end float on the big end to keep it in place.?
Lots of questions I am sorry!
Ian   
10/04/2010 10:19:37
Hi,
I am approaching a big end rebuild on my JAP LTOWZ engine (1000cc water cooled V Twin from the 30s). The original big end bearing was a crowded roller bearing (loads of rollers no cage) but I would like to modify this to add a light alloy cage.
The cage then is an annular ring with a series of rectangular slots to take the rollers.
Phil Irving in his seminal work "Tuning for Speed" recommends milling out the slots with a woodruffe cutter then filing the ends square but I am afraid I don't have it in me to do all that filing.
Do we have any alternative techniques for forming the cages without the filing? I have milling (manual and CNC) and turning of course.
I have wondered about making the cage in two pieces - a plain ring on one end to close off all the slots, but am not sure about how to secure it.
Ian
Thread: CNC engraving
09/10/2009 21:35:03
Here is a vide of a commercial tool in action;
If you go to about 1.06 into the vide the operator moves the tool against the spring which gives me the impression that it is a pretty light spring.
 
Ian
06/10/2009 21:55:01
Hi Paul and Bob,
 
Thanks for your thoughts. The thin brass I used for the dash board badge was clamped down onto a piece of wood which gave a somewhat eneven surface - I had three passes at engraving it getting down to about 10 thou in total from memory. The first pass was a bit hit and miss as the brass was not completely flat, partly as a result of the clamping method and partly as a result of it being cut out of a bigger sheet with snips. Note that this was with a tool in the normal spindle. Going to a spring loaded tool was hopefully going to allow me to get the engraving done in one pass.
 
Have a look here to see a commercial offering http://www.2linc.com/engraving.htm 
 
I had a go with my spring loaded tool on the end of a reproduction Best and Lloyd oil pump plunger - the "happy man" logo has to go onto a domed knob. I was not confident enough to set the cut depth to .1" say and let the took find its own depth as it traversed across the domed surface.
 
Have you any feel for whether the spring should be "strong" or whether I should be able to lift the tool with one finger for example? Perhpas I have to just risk an engraving tool and "suck it and see".
 
Ian
 
 
04/10/2009 22:12:24
I have been exploring CNC engraving on my Denford Easimill and have made myself a spring loaded tool holder. This is essentially a spring loaded mounting for the Axminster Power Tool centre heavy duty flexible drive which I found a recommendation for as a sounrce of a few tens of thousand rpm.
 
I am using 1/8" dia shank engraving tools sourced from Ebay and would like to get  an idea of how strong the spring should be. I read the MEW article on a spring loaded tool holder for engraving but it did not give an indication of the strength of the spring.
 
Anyone got any ideas?
 
I will put anexample of some engraving in amongst my photos.....
 
Ian
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