Slitting saw advice

I vaguely recall only slitting one side of the eccentric, so it could be tightened up to compensate for wear (as if it will ever be run for THAT long!) I'll go and check...

...indeed that IS what I did. The cut is dead square and very neat - I am totally bewildered how I could have made such a good job of it without a very thin slitting saw. I can only think I used a razor saw and ran it along the top of the vice?

If only the rest of the thing was as well made - it was my first 'proper' attempt at model engineering!

Neil

Hi Bob

You should not have a problem with slitting saws, i use all sizes down to 1/64" its the same as useing a hacksaw dont force it let it cut itself and you wont have any trouble. You need to drill the bolt holes first then saw all the way through bolt it back together and then bore the hole to fit crank.

Regards

Stan

The usual name for a 'jeweller's saw' is 'piercing saw'. The standard arrangement arranges the teeth pointing to the handle, so you cut on the pull stroke (like Japanese joinery). This breaks fewer blades. Blades of a wide range of thicknesses and tooth pitch are available - but for this sort of job use the coarsest you can get. Just key 'piercing saw' into E-bay and you will get a selection of saw frames and blades.

But I expect you have finished the job by now ...

Cheers, Tim

Hi Bob

This from a complete novice's point of view - slitting saws strike me as potentially being one of the most dangerous pieces of equipment I have come across in Model Engineering should anything go wrong, I've only tried it a couple of times (although without any problems I should say) and is the only activity I have come across when full face protection screams out at you or me anyway! Definitely go slowly I would say - just something to think about...

Cheers.

Allan.

Edited By Allan. on 17/02/2014 16:52:42

None of the tools we use in engineering are toys and should be respected at all times, eye protection is the order of the day! Use sharp cutters and think what you are doing.

Tony

Edited By Tony Pratt 1 on 17/02/2014 17:24:07

Double post

Edited By Tony Pratt 1 on 17/02/2014 17:23:33

Hi Bob

I'm going to dare to partially and respectfully disagree with Tony. Having grown up from a young age working with lethal machinery you develop a sense for these things - just eye protection is not enough for this, especially as you sound to have no experience using them yet - but I would say better safe than sorry at all times. It takes no longer to reach for a full face mask than it does for the safety glasses - my full face mask cost about £10, the slitting saw is the only thing I have used it for and I wear safety glasses at all times for everything else...

Cheers.

Allan.

Thanks all for the advice. Perhaps like many coming home from a work environment where H&S is applied to the highest standards, standards in the home shop leave a bit to be desired. Am I the only person on the forum that taken the safety guards off their lathe, and mill, oh and the table saw. I think the guy on sky, who's hame escapes me, used to say that the guards are removed for filming purposes! I do have a selection of safety goggles but perhaps will invest Ina visor.. I did my apprenticeship with an excellent guy who I will be forever grateful to for trying to impart many years of knowledge and experience into a teenager. One piece of advice was to always use your less dominant hand the putting fuses back in. I'm not sure that type of H&S risk assessment would be acceptable today!

Im into some major DIY at present so the slitting saw advice is yet to be put into practice.

Bob..

I would say a slitting saw running fast enough to spray swarf is running far too fast.

Neil

Nope. And you can add Chopsaw Hand held Circular Saws and Polishing machines to that list. Chop saw is shortly going in the crusher, it is quite dangerous.

graham.

Slitting saws remind me of the Kung Fu throwing stars that enjoyed a brief (thankfully) popularity in the seventies when I was at secondary school. As you can imagine nobody at school was wearing any protection.

Gary

ive never used a slitting saw on an arbour. i always use a junior hacksaw with a new blade on miniature loco eccentric straps. ok they then need cleaning up in the vertical slide or mill, but that doesnt take very long. then soft solder together, drill the bolt holes (tight clearance fit, i usually turn up fitted bolts anyway), then machine to width both sides and bore to ID to a plug gauge. when holding in the four jaw be very careful you dont apply too much pressure with the jaws. then heat up to melt the soft solder and wipe off any excess. this was pretty standard as per LBSC . i have an old iron for clothes ironing i use for soft soldering such jobs - nice flat surface.

i usually bore mine dead on then apply engineers blue and scrape to fit the eccentric sheaves. btw i always fit proper bolted on eccentric rods - and i dont really like the combined rod and strap casting in bob's initial pic, though i did do a Stuart Turner 10 that way years ago. it will be easier to machine plus look much better with a bolted on eccentric rod.

cheers,

julian

With the Eclipse Junior hacksaw you can if need be cut very accurately by clamping two bits of 1/4" steel, one each side of the cutting line, with a firm sliding fit for the blade, use a new blade, lubricate it well, either oil or candle wax. Don't push it, just let the saw do the work, or do as I did and build a little power hacksaw. Ian S C

Edited By Ian S C on 18/02/2014 11:31:54

When I was an apprentice all the horizontal milling M/C’s were fully guarded but some idiot still managed to get his hand near the cutter and lose some fingers! If you do not respect tools and machines no amount of guarding will prevent injury.

I totally agree with guarding grinding wheels as they can be unpredictable but as a Toolmaker I found guards intrusive on manual machines. The advent of CNC machines in industry has taken guarding to a whole new level and quite rightly so.

As I said before your eyes must be fully protected at all times as they are so fragile and once they are gone they are not coming back.

Tony

H&S tips

1. If you must wipe the soldering iron on the leg of your overalls, make sure they are cotton, not polyester (ouch).

2. If using a slitting saw in an arbor, ensure the keyway slot is NOT used, if the saw jams, it can then slip rather than fracture (ouch)

Steve

Over the years I worked in engineering I must have sli tsawed thousands of items. Most jobs came in batches of 100 and slitting rocker arm eyes was a common job. Once you had broken a couple of slit saws the sound of the foreman shouting was enough to focus the mind such that you found out how to do the the job quickly enough to make some piecework and slowly enough to not break any cutters.

What I learnt was this . 1. Never use a key 2. Do the arbor up as tight as you can ( 2 apprentices and a twelve foot scaffolding pole usually does the trick) 3 Never use the feed, stand at the end of the table and carefully feed the cutter in by hand, if it does snag , quickly wind it back to free the snag and carry on. The only other tip was to get the batch done before the inspector came round again, only to find that the cutter had wandered half a thou off centre causing him extreme distress. I never saw a guard on any of the machines on the bay I worked in, no time for all that , we were on piece work. All gone now https://www.youtube.com/watch?v=i3UVz4F3wyw

stevetee,

If you don't have it already ...

There is apparently a free booklet available about Mirrlees site history

see here

MichaelG.

Sorry all, back to slitting. I hope to be able to find a bit of time at the weekend to open the slitting saws that Santa bought me and have a go at my 10V crankshaft. Just a bit of advise from the wise on how I should feed the saw into the workpiece. I have tried to sketch my understandings of the options in the PERKO-CAD sketch, which are:

1) plunge cut

2) up cut

3) down cut

Bob,

I would use (2)

MichaelG.

without any doubt number 2 ,the other 2 are called climber milling which allows the cutter to grab the work piece and try and drag it in .like others have said slow speed personely I use between 60/100 rpm on small up to 2" then half that for large ones, also high speed will just burn out your 10 quid cutter ian c