Member postings for Steve Crow

Thank you Michael, that got me thinking. If I hand grind the teeth of a piece of junior hacksaw blade, it will fit nicely in the 5mm slot of the holder. I could sandwich it in place with a rectangular insert with about 3mm of blade protuding.

Do you think this might work?

The trouble would be finding all-HSS junior blades and then drilling a clearance hole for the M2.5 screw.

I tempered it in a domestic oven to around 190 - 200C then stuck the tip in a potato and re-tempered the shank. This was from Tubal Cains heat treatment book.

The cutting part is on the right so I can get as close as possible to the chuck - even a couple of mm helps.

Just use a domestic oven with an oven thermometer. Then stick the tip in a potato and flame the shank to blue.

Now I'm sure that this not a new or original idea but I'd thought I'd share it anyway.

I need to cut some 0.5mm wide grooves around 2mm deep in 1/2" brass bar. I don't have access to a grinder and the only insert system i can find for that size is the "Mini-Thin" from MSC at around £70 for a holder and £18 each for the inserts.

I had some small scrap pieces of 1/16" Ground Flat Stock and some mild steel 1/4" square bar so made these-

The pictures are self explanatory. The top "insert" has been filed to shape, hardened, tempered and sharpened with a diamond lap. The bottom insert is a soft blank.

Some more photos-

This hasn't been a success so far. After cutting two good grooves things got a bit noisy and warm. The blade has lost it's temper now and will need rehardening. I will also have to pay a bit more attention when it comes to sharpening.

I didn't put any rake on this as it was for brass but I've noticed that a lot of parting/grooving systems seem to have a negative rake. Is there a reason for this?

Any hints, tips or questions are more than welcome.

Cheers, Steve

Edited By Steve Crow on 27/08/2019 14:28:47

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I've been using **GT inserts on my Sherline all weekend with 3mm silver steel. Unsupported, at least 15mm hanging out of the collet, half of that turned to a long, 6 degree taper. Great finish and so little deflection you can "rely on the dial"

I was originally planning to use a female centre but there was no need.

These inserts make turning SS like turning EN1A.

Chris, I urge you to try these. If you want to hone your turning skills, you can be up and running straight away. Just make sure they are centred well and run them at full speed below 4mm OD.

I understand the urge to follow your mentor but that can come later when you have more turning experience.

Also you talk about brazed tools for precision micro work. Most of the work you are going to have to do is not precision micro work, for example your centre punch and the other tools you are going to have to make.

Following the advice of the forum and getting a good, all purpose tool is going to get you moving forward towards your goal.

I don't mean to sound all evangalistic about these inserts but since I've started using them (on forum advice), there has been one major thing not to worry about (tool sharpening) so I've been able to concentrate on making stuff.

Just try it,

Steve

Some great little engines there! The one I'm building is to my own design with two horizontally opposed cylinders. It's not a boxer, the two con-rods share a single crank journal.

I think I'm going to try brass cylinders with silver steel pistons.

Boring the cylinders with a d-bit from the piston stock? Is this a valid method for this application?

Or will it need boring slightly small then lapping out to fit?

I'm not sure on the kind of fit required for an air powered piston of this scale.

Any tips or advice would be much appreciated.

Cheers, Steve

Thank you Dave, I've never heard of graphite being used as a material in an engineering context. Is it a material that's readily available and used?

Nick I've heard that about wear and it make sense. That is the principal behind watchmakers black polishing where hardened steel is lapped on tin or zinc plates.

I'm planning to make a small air powered piston engine. It's going to be 6mm bore and stroke. I'm not expecting it do any real work, just a demonstration project.

The cylinder will have an inner sleeve, plain, no ports or anything. I'm hoping to keep the walls thin, 7mm OD if possible.

The piston will be plain with no rings.

My question is, what are the best combination of materials for these?

I would like the piston to be silver steel as I can use 6mm stock and make a D-bit from the same to bore/ream the cylinder sleeve.

Should the sleeve be bronze or would brass do?

Would I be better off with an EN1A sleeve with the piston brass or bronze?

I take it that steel on steel is a no-no. I would rather not use cast but if it was advantageous I'd give it a try.

Has anyone built one on a similar scale? Or possible a Gasparin style Co2?

Cheers, Steve

Edited By Steve Crow on 20/08/2019 18:36:08

I use 8mm collets in my Sherline lathe and mill.

Definitely get the headstock adapter.

It would be a good idea to splash out on the WW tailstock adapter and the adjustable tailstock tool holder. With these you can achieve near perfect tailstock alignment and the ability to hold tiny drills. You can also make custom tools like long or half centres for the tool holder. It's a very useful tool and really ups the level of precision attainable.

I also use a collet holder on the rotary table.

Be aware that Sherline make collet adapters in two different types - WW and 8mm. These vary slightly in size of bore. Have a look at the Sherline website for sizes and other details and carefully measure your own collets to make sure you don't get the wrong type. Maybe use your new dial calipers!

Steve

Chris, with respect to your mentor, I strongly advise that you take the advice of the forum members.

I did and I don't regret it.

I had a similar problem regarding the Sherline. See my thread "A Kitchen Table Workshop - Grinding Problems" (I don't know how to link it). I took the forums advice and bought a holder and inserts and some HSS Co5 6mm tools.

Centre them properly and you'll be getting excellent results straight away. They are fine with silver steel down to sub-millimeter diameters. I've cut a M1 thread with the HSS and turned a 0.5 diameter with the inserts all in silver steel with a good finish.

Take my word, try these and you can be cutting metal as soon as possible. There is no substitute for getting stuck in and making some swarf.

Steve

Thanks everybody, this was a cheapy so I suspect it's not that hard. My mill will take a full length taper, it's just I don't want to keep winding up the mill head that far.

It has a tang on the end at the moment.

I'm going to make a slitting saw arbour out of it so I think I'll need a drawbar. I plan to drill the end and loctite a threaded insert into it if that sounds viable.

Steve

I've been using those very same inserts all morning to turn tapers on 3mm silver steel on a Sherline. Run it at full speed - great finish.

I've just bought a Soba 1MT soft end blank for less than the price of a pint (I do live in London)

A Sherline headstock has half length 1MT taper from the big end so I need to cut off the little end and drill and tap for a drawbar.

Now I assume that the taper end of the blank is hardened and I don't fancy trying to part it with the relatively puny Sherline rear parting tool.

Any suggestions for cutting it? Maybe start a groove with a carbide tool then get the hacksaw out?

I only have a kitchen table workshop and no grinding facility.

Also, doesn't a Cowells headstock use the little end of a MT1? If so, does anybody want the offcut when I'm done?

Steve

If you have a look on the JB website there is a link called"Applications for toolholders" This will help you visualize the various types and what they can be used for.

I find the SDJCR type useful for smaller stuff.

I have no connection to the company, It was recommended to me on this forum and I found the quality and service to be excellent.

Incidentally, what workholding method are you using on the Sherline? Collets or chucks? It has no bearing on your question, just curious.

Steve

I get excellent results on my Sherline with silver steel using CCGT inserts with a 6mm JB Cutting Tools holder.

Also with Arc Euro 6mm HSS Co5 tools.

They also work great with brass and EN1A.

With small stuff, It's important to get the centre height bang on.

Edited By Steve Crow on 15/08/2019 17:37:05

If you are going down the horological route, you are probably going to have to make a few tools.

Get yourself a good micrometer. A Mitutoyo 103-137, the entry level model, can be had new for under £50 and will last you forever. Practice using it on known diameters until you get a feel for it. I was taught as an apprentice but I'm sure there are guides on the internet.

Calipers can get in places micrometers can't. They can also measure internal and depth measurements. Technique plays a big part in getting consistent measurements. I use the same method as Mick mentions above.

Cheap digital calipers are hit and miss. About 6 years ago I bought the cheapest one I could find on ebay for rough work. It still works fine with accurate and consistent readings and it doesn't eat batteries. Maybe I was just lucky.

Yes the 20mm have a 5mm bore and the 25mm is 8mm.

I could do with a few different thicknesses but at a tenner a pop I want to be sure!

Hello again Chris. Forgive me if you all ready know about this but I've a Sherline lathe tip I'd like to pass on.

Get a couple or three of the 1/4" Two Position Tool Post (part no. 3003) and load each side up with cutters and centre them. When you need to change to a different tool, simply swap the tool posts. It takes seconds and doesn't interrupt the work-flow.

At around £16 per post, it's a lot cheaper than a quick change system.

They also make tool posts for 3/8" if you need to do something a bit beefy.

Steve

I see that Chronos and RGD stock mini HSS slitting saw in 20 or 25mm OD in a large range of thicknesses.

Has anyone any experience of these and what is your opinion? I don't want to go to the trouble of making an arbour to suit if the saws are dubious.

I can't find any other suppliers stocking saws of that size.

Hi Chris,

I also have a Sherline lathe and recently got a set of four 6mm HSS Co5 cutters from Arc Euro Trade. I've found them to be excellent and very sharp. I managed to cut a M1 thread in silver steel with the 60 degree tool. They should be easy to keep sharp with a diamond lap as well.

I also got an insert tool and a few different inserts to try from JB cutting tools. Again, great quality and service.

I've used all the above on brass, mild and silver steel so should be ok for all things horological. Not tried them on pivot steel though!

Steve