Member postings for Mike Crossfield

Perhaps unwisely, I agreed to make a kitchen utensil for my sister in law. It's a potato masher - basically a disc with a pattern of slots, mounted on the end of a shaft with a handle on the other end. Yes, I know you can buy such things, but I'm tasked with copying the design of a much-loved tool which has finally expired, and which is no longer availed commercially

Anyway, I thought that stainless steel was the right material to use, so a rummage in the scrap bin brought a suitable sized piece of 2mm plate to the surface. Now, I have little experience of working with stainless, but my attempts to machine this plate have been less than satisfactory. After just 1 slot with a new 5 mm carbide slot drill running at 500rpm the cutter has lost its edge, and the slot is very ragged. I guess the problem is the material work hardening. Am I using an unsuitable grade of material, or is my technique wrong? Is there a free machining version of stainless sheet?

+1

Mike

Thanks for that Robbo. That URL works for me (iPad/safari).

Mike

It would be really helpful if someone who is able to access the site (I still can't) would send the organiser a message telling them about the problem. There may be something they can do at their end.

Mike

Ian

It's not just you. I have exactly the same problem.

Mike

Canyon

When I rebuilt my DW some years ago I replaced all the oilite bushes, and I sourced correctly sized parts at very reasonable prices from Ashley Power in Poole. Website at www.ashleypower.co.uk. They don't seem to list imperial sizes in their online store, but you can order them by phone.or email.

Hth

Mike

Rod

"ACS300" covers a family of different inverters covering .375 to 11kW. There is no single unit covering this range. What is the full ACS code number on the plate on the unit you have? You might only have the 1/2 hp version.

Something very obvious, but I'll mention it anyway. Which version acs300 do you have? Is it rated for a 550W motor?

Nick

If you ever get to the bottom of the CT designations do let everybody know. Some (but not all) of the oilite bushes used on Myford lathes are specified on the parts lists using CT numbers, but I've never found out how to decode them.

Ok. My overall take is to pick up the scribed mark using a wobbler or optical device on the mill. Use a s spotting drill to create a centre, follow this up with a stiff reaming size drill (no pilot), then ream.

Thanks all

Mike

Thanks for that Duncan. I like the sound of the optical centre finder. I feel another project coming on!

Thanks Jason, that sounds like an improved approach which eliminates the pilot drill, which I had doubts about.

I have a wobbler of the George Thomas variety, but my deteriorating eyesight makes it hard to line it up really accurately with scribe marks. I'll have to try harder with magnification and better lighting

MalcB

I do have a milling machine equipped with DRO, and I often use it for coordinate drilling. My question related to drilling holes starting from scribed locations, such as those created when planting clock trains.

Emgee

Using a hardened drill guide would be specific to only one size of drill, so not a general method, and how would one go about accurately positioning the guide over the scribe marks?

I sometimes need to place holes in precise marked locations, and I wonder if the technique I've used for years is optimum.

Say I want an accurate 1/4 inch hole at a scribed location on a brass clock plate to an positional accuracy of (say) 5 thou. I would start by dot punching the scribed location using an optical centre punch. I would then move to the drilling machine and use a short, stiff, CNC style centre drill to create a centre. I would then use a small drill, say 3/32, to create a pilot hole, and follow this up with a 7/32 drill, and finally a 1/4 reamer (hand reamer, used in the drilling machine). Sometimes I get the accuracy I want, sometimes I don't.

Would it be more accurate to omit the somewhat flexible pilot drill, or is there a completely different sequence which would lead to more consistent results?

Neil,

It's a spring for a Harrison maintaining mechanism on the barrel of a long case clock. I need a piece about 90 mm long.

Mike

Thanks for all the replies. It looks like I!'s probably not available. At least not in the very small quantity I need at a sensible price. I need it for a maintaining spring in a clock barrel. What matters is stiffness after hardening. Doing some sums just now it looks as though a round section would need to be about 20% greater in diameter than the side dimension of a square bar for the same stiffness. So substituting a round bar for the 1/16 square bar would means I would need a round bar 0.075 diameter. This is pretty close to 2mm, which is readily available size. So I'll go with that.

Mike

I need a short length of 1/16 inch square silver steel for a clock project. Tried all my usual sources without success. Anyone know where to get some?

Mike

Uk Tool Centre has after at the moment for Faithful files handles with prices from £0.45. Just ordered some.

**LINK**

Mike

I'm interested in building the Claude Reeves gravity regulator clock, and I would be grateful for comments and advice from anyone who has experience of the design. I would also be interested in comments on the two books which describe the build, one by John Wilding and the other by John Payne. Which is best?

Mike

When I was rebuilding an ML7 about 20 years ago I ordered up a pair of these bushes from Myford. When they arrived I was surprised to find they were soft rubber. I also discovered that they didn't appear to fit. After dialogue with Myford I learned that they were not fitted to very early models, and that they were a later mod. to reduce rattles. I may still have them, and if so you can have them for a modest donation if you can't source elsewhere.

Mike