Member postings for JohnF

I have seen some of the woodturners doing exactly that when making screw top turned wooden boxes - fascinating to watch !

John

In the absence of any sophisticated threading equipment and undercut at the shoulder is the best way forward, as a rule of thumb the U/cut dia should be the thread root dia -- .002" to -- 0.005" and the width approx 1.5 x pitch. A small rad on the LH corner of the U/cut tool and the RH should be the thread flank angle.

You can also start in the undercut and run in reverse with the tool inverted [beware screw on chucks] also a useful technique when thread cutting into a blind hole.

John

David, as has been said there are full form and partial form but think about what you did/do when you grind your own tools ? they are partial form and good enough for most jobs in the home workshop, one advantage you do have with home ground tools is you can add the correct root rad to the tool. As far as the crest goes the best way is to truncate the thread thus removing the need for a crest radii . This was standard practice in the 1960's and beyond and I was working in the Aero industry all cut threads were truncated.

I still use home ground tools but also tipped tools for these I purchase full form tips for each thread size/pitch

John

Difficult to say for sure but it looks as though the tool is as close to the back of the slot in the toolpost -- you can probably move it outward towards the machine centre thus putting the cutting edge closer to the machine centre.

Chris, I think welding may cause you more problems than you have already, personally I would not try to heat treat to whole tool, just do the cutting end. Looking at your photo suggests that the tool is not tempered evenly as one would expect if done in a oven ? The threaded end has been much hotter then the cutting end -- blue // pale straw.

I would suggest heat the cutting end to cherry red and quench in oil [not water] then degrease, polish with new emery temper to a dark straw in subdued daylight, Don't heat the actual end, heat further back and allow the colours to run up the steel. Quench in oil.

Hope this helps

John

Hm ! I would be cautious -- what do they contain, are they "approved' to our standards ? many solders and the like can give off noxious fumes when heated. Think about the solders of not too many years ago available here and now no longer due to H & S

Any more thoughts ?

John

Does the chisel have to be 8mm for the whole length ? Engravers tools and old fashioned stone masons hand chisels are in many cases much smaller at the business end than the handle/shaft.

John

Phill, sent you a PM see the flashing INBOX at the top

Guess I'm lucky ! Been in my nice cool NW workshop most of the afternoon -- outside temp is 30deg but at 20deg W/Shop is fine. Lucky its underneath the lounge at the back of the house and gets only early morning sun.

Now need to venture out and treat my Labrador to a swim !

John

A wee bit late but here is a photo of one of my chucks as supplied originals from Myfors, the screw is 3/8" x 20 BSF underhand its 1.75" long

Hi Pete, i have a Boxford G200 and the column does not drop into the cabinet, the head rises and falls similar to the Union machine.

John

Edited By JohnF on 08/07/2022 11:28:42

The issue number [No 318 on the photo] use one colour set for all copies BUT a different colour for the copy that has the series index in thus its easy to find this copy from "the pile" -- say black type on yellow background.

John

I have a pdf file with the instructions for this machine, If anyone wants it please PM me with your email address and I'll forward it to you.

John

Just search for Thor hammer spares and you can buy the copper or hide inserts for a few pounds -- not worth the trouble of making them I think

John

PS Simon like the lead casting method ! I cast lots of lead bench vice jaws.

I use Dickson QC tooling and have done since the early 1960's when they first appeared on the market, I would not be without it ! There are many other types available now and lots of clones of every type, originals are best but expensive so if buying a clone choose wisely form a well known supplier, Bison are excellent quality and interchangeable with Dickson -- not so with many of the clones.

For you machine I think the S1 [Dickson] or T1 [bison] size would be OK, lots of tables available so check these out. Another type thats popular is the Swiss pater Multifix system, more complex than Dickson IMO.

John

To put it into perspective its about a 340 mile round trip so 10gall of fuel now costing £90 but before the same 10 gall would have cost approx £60 [1.35/lt] a difference of £30 considering there will be 4 travelling its not a deal breaker.

John

Exactly James, I have been doing this from 1960 -- same reason, my mentors instruction -- several different ones and it does work ! you get a less runout by progressivily tightening the chuck working around the holes, I also always start at the same hole every time.

John

Chris your location may help if there is anyone close enough to visit and assist with information etc !

The Drummond may have been a treadle powered lathe if the large flywheel on the RHS is or has been part of it ? As Hopper says there are collector / users of these vintage machines so some research on t'internet may yield results.

The Colchester, if you search online, ebay and machine sellers the prices vary wildly from under £1000 to £4000 + BUT it depends on condition and what accessories are available with the machine. As you will appreciate your machine will need considerable remedial work and this will affect the selling price. However Colchester are a popular machine for home users .

Good luck with your sale

Not familiar with your drill and it depends how old it is ? However all the ones I have has occasion to work on the chuck is fitted on a right hand 3/8" UNF thread several had a screw inside the chuck body to lock it in place -- hope this helps

John

Edward sent you a PM see the black box flashing at the top of the page

John