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Post by sulvarbir on Jul 7, 2019 4:44:47 GMT
Hi, relatively new wood turner. I purchased SK 100 pack & last night tried to turn a small oak blank that I received from G & S timber when I purchased the ProEdge recently.
I thought the size of recess/mortice was to big for blank diameter. Anyhoo this blew out after an internal catch. I decided to make a tea light holder & the 35 mm Forstner drilled hole was to small. The catch happened when I was using a Sorby skew to increase the internal diameter.
Is there anything that would give me a smaller diameter mortice that fits the chuck?
Kind Regards
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Post by Pete on Jul 7, 2019 10:52:04 GMT
Hi Sulvarbir Hard to say what happened here, I am guessing that you were using the skew in scraper mode to dovetail the edge of the mortice, and hoping it was a small / 12mm or smaller skew.... What size was your free oak blank? what size were the chuck jaws? how was it mounted to turn out the 35mm start point? My method of turning an internal dovetail mortice varies by what size / shape timber I have, but say it's 150+mm diameter with a flat on both sides :- - Mount face side (top) of the blank on face plate
- Measure my chuck jaw set external minimum size
- Shape the outside of my bowl allowing sufficient flat space for the chosen jaws plus minimum of 10mm
- Pencil mark the jaw size plus 1mm tolerence
- Use my 6mm parting tool to sink a square sided groove to te depth I want usually 5mm,
- Use the bowl gouge to remove and make pretty the base of my mortice.
- Finally I will gently in scraper mode use a small skew (10mm) to turn the parallel side wall into a dovetail.
This method is able to cut any size mortice to match any dovetail jaws, if I am going for a 25mm then I would be very cautious using the 10mm skew as it is close to the centre, and I do have a smaller one. |
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Post by sulvarbir on Jul 7, 2019 12:08:12 GMT
Hi Pete,
I’ve attached photos of blank. As you can see the mortice is far to big for the piece of wood.
I’ve recently spent a valuable day with Martin Sagan- Smith were we used a face plate to shape bottom. In this case the face plate that came with chuck kit was to big so used 8mm screw to turn base. I had to keep taking it off to check against closed jaws of chuck before expanding into recess. I was expecting about 56mm but ended closer to 70mm.
I was actually widening the hole for tea light when the catch happened & whilst I’m not a rocket scientist I think the pressure was to much for the wide mortice & went. I think I need to buy smaller c jaws for the chuck.
I’ve just ordered a Sorby thin parting tool for tenons.
Many thanks for your kind advice.
Apologies I think image attachments are disabled or my account.
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Post by Pete on Jul 7, 2019 12:42:33 GMT
I didn't get the pictures  once logged in you should be able to add pictures with the Add Attachment button top right of the full reply screen (not on quick reply). Yes 75mm Dovetail Jaw's are pretty big, I often turn 250mm to 300mm bowls on a 50mm dovetail jaw set, For tealight holders would probably use smaller still, so yes smaller jaws OR use an external tenon mount and reverse it in the chuck to turn it off afterwards. Skew was still the wrong choice, easiest way is 40mm Forstner bit, but if you want to turn it I would probably do that with a spindle gouge slightly curving in the side wall as I go this will keep the tealight held at the bottom while allowing it to be lifted out at the top.... I need to say you should not put tea lights directly into wood... there is a fire risk... said it, and I still do it myself, but only for my own use I wouldn't sell one without a glass or brass liner. |
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Post by sulvarbir on Jul 7, 2019 13:09:46 GMT
Hi Pete You also need to select desktop (doh) I've ordered a couple of brass holders from Turners Retreat but ironically I couldn't see diameter size. The 40mm forester will have to wait as I have just acquired a 25mm and 35mm (not to mention the ProEdge) I will add the third attachment separate reply that shows the blow out. Kind Regards Attachments:
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Post by sulvarbir on Jul 7, 2019 13:10:24 GMT
And third image Attachments:
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Post by Pete on Jul 7, 2019 14:58:27 GMT
Yes your answer is smaller Dovetail Jaws, the remaining wall thickness would support a job without a catch! but obviously gives too fragile a wall for a harsh cut or a catch.
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once logged in you should be able to add pictures with the Add Attachment button top right of the full reply screen (not on quick reply).
