Shaper keyway cutter

[Ian]

Had a 96-tooth gear I wanted to add to my 7x14 lathe for a little finer finish feed rate, but the 7x14 standard keyway is 4mm wide and the gear is from the 8x series of chinamarket lathes that have two compound pairs of change gears and really oddball tooth counts use 3mm keys. As usual I had to make a tool to make a tool to make a tool so I could use a tool to make what I wanted to make in the first place.

5/8x18 all thread rod from an 18-wheeler brake chamber repurposed here. Normally the cutter shank would be put directly into the clapper box but for this little stuff the Armstrong holder worked fine.


Things I learned today:

No matter how hard you try, no more than 1.5 threads of an 8x32 grub screw will start in a 6x32 hole.

It is not possible for the human brain to think in Metric and Imperial at the same time. Pick one based on machine tool dials, convert the measurements if necessary. Needing to dial in .12mm on a thousandths dial and having to stop and do the calculation is very frustrating.
Cheap HSS drill shanks do not oil-harden but do water-harden.

It is more fun and accurate to do in an hour with machine tools what can be done in five minutes with a square file, but only if machine work is an enjoyable pastime for you.

 

[Snakeoil]

No matter how hard you try, no more than 1.5 threads of an 8x32 grub screw will start in a 6x32 hole.

This has to be the ASoBC quote of the week.

 

[Brad]

Some things need to be proven regularly.

 

[Petrol & Powder]

"....No matter how hard you try, no more than 1.5 threads of an 8x32 grub screw will start in a 6x32 hole...."

I am almost certain there are corresponding combinations to that rule in other thread sizes and I have discovered most of them.

 

[Snakeoil]

"....No matter how hard you try, no more than 1.5 threads of an 8x32 grub screw will start in a 6x32 hole...."

I am almost certain there are corresponding combinations to that rule in other thread sizes and I have discovered most of them.

Anyone who has ever restored a vintage British car or motorcycle can confirm this in spades. The Brits had at least 3 different thread forms, Whitworth, BSC (formerly CEI) and BA used on vehicles and very early vehicles probably used even more. I know there are more Brit thread forms. And to complicate things further, they were often mixed on a single vehicle. The issue is/was us dumb Amurcans generally had idea about anything but SAE threads back in the 50's and 60's and could only buy SAE threaded fasteners at the hardware store, so that's what was used. And with a big enough wrench you can twist just about any SAE thread into a similarly sized Brit thread. The only thread that is just about a perfect match is 5/16-18. The difference is SAE uses a 60 deg thread and the Brits were partial to 55 deg threads.

 

[Petrol & Powder]

Trust me, I’ve done my sentence with British machines. We referred to MG as “More Grief”.

The Brits never could decide if they wanted to use Whitworth, Metric, or something in between, Toss in some Lucas (The Prince of Darkness) electric parts and good ole rust, and you were in for an adventure.

 

[smokeywolf]

I always love to see resourcefulness.

Now if you had a small surface grinder you could grind broaches out of toolbits and tap shanks. No heat treating required.

Toolpost grinder in the lathe?

 

[Bret4207]

Just as an aside, because I was looking the other night, tool post grinders are freakin' EXPENSIVE!!! I was looking for on for my Logan. Hokey-Schmokey! I could a couple hunnert, but they start close to a grand- USED!

 

[smokeywolf]

Can't remember what brand mine is; I think DuMore.

 

[Ian]

I have a tool post grinder, says "Black & Decker" on the side and has a 1/8" collet for, you know, "Dremel" type accessories. Fastens to the tool post with a bar clamp.

 

[Snakeoil]

Just as an aside, because I was looking the other night, tool post grinders are freakin' EXPENSIVE!!! I was looking for on for my Logan. Hokey-Schmokey! I could a couple hunnert, but they start close to a grand- USED!

We had a garage sale at the lake a few years ago. Guy had this huge case iron pedestal stand with a buffing wheel on it. I have several buffing wheel set ups, but that pedestal truly caught my eye because it was big, heavy, old and... well... PERFECT for a grinder. It was late in the day and I wandered over to look at it. The guy comes over and says "Make me an offer. I don't want to carry it back into the barn.". So much for his negotiating skills. I tell him 5 bucks. He says $25. I said $15. He said sold. The scrap value was more than $15. So I bring it home (heavy mutha) and clean it up and start to check out the buffer. The name seems familiar to me and it strikes me as being extremely robust in design. Then an extra synapse fires and I realize Dumore means it is a tool post grinder. I look it up on the web and the spindle replacements are over $1000.00. We had Dumores in the shop back when I was a machinist. This is a lathe tool post grinder.

So, Bret, maybe we can make a deal here. This thing is not here at my camp, it his home in Albany. Since getting it, made a new belt from nylon webbing and have used it as a buffer. It only has the drive drums that are on it so you would need to make or buy others if you wanted to alter the speed. The belt guards are missing and made a guard from 1/4" luan and some old containers just to keep me from hurting myself.

I will take pic when I get home. I'm not looking to rape anyone here. If I was, I would not have told you what I paid for it. But it has value and I would just use the money to buy another toy or do something nice for the wife. It is big. Not a Dremel toy. I know Logan lathes and this should work well on that machine. If I had a bigger lathe, I would have brought it back to tool grinder statis. You will also need to machine a round tool post mount to hold it. Although, the mount on the pedestal might be something I could remove and provide with the machine. Have not looked at it closely in years.

If you are interested, I can bring it to the lake and we can meet up somewhere. I'm on Oneida in case I did not mention it before. So, not that far from you. We might take a ride up to Clayton for the Need for Speed event at the museum. I can toss it in the trunk and meet you somewhere.

Stay tuned for pics.

 

[Snakeoil]

I promised pictures of the tool post grinder. So here they are. The aluminum motor base has been weld repaired and done very nicely.

I'd rather horse trade this for something rather than sell it. If I can cut that center column off the pedestal, I'll do that. Assume a bolt goes thru the center to fasten to the compound on the lathe. Been too long since I used one of these. You can tell the size of the machine by the size of the buffer wheel.

 

[JWFilips]

Cool stuff way beyond me!

 

[Ian]

That thing is an absolute beast. 3/4 horsepower on a tool post can do some serious work!

 

[Bret4207]

Snake, thanks for thinking of me. Let me do a little research, my Logan is a little 10 incher, I'm not knowledgeable enough to get the whole picture, but I know things can get oversized. Again, thank you for thinking of me!