Hello Mark

You need a 60 degree cutter to make dovetail slides

its all a matter of where you measure the angle from!

the ones I have are 22 mm and 25 mm

the 25 will do all the dovetails on our sort of projects

regards

Jim

Jim is spot on here.

Obviously a square cut is 90 degrees, so 90 – 30 = 60 degrees. The 30 is measured from the horizontal plane, whereas the cutter is working in the vertical plane, so make sure you clamp the job the correct way up.

When you have the pieces in your hands it will become clear.

So send back the 45 and get a 60!

Phil

Edited By Robbo on 18/05/2013 09:41:35

Hope you get that sorted OK. Take it gently with the cutters and they will last a long time. If they rub in the corners you can put a TINY amount of extra relief on the corners with a sharpening stone. This only means the inside corner of the dovetail will not bet 100% sharp. It is essential to take the sharp outside corners of dovetails off anyway(as any tiny interference completely spoils the fit) , so this makes no material difference.

Look at the pic below and note how the dovetail only contacts on one of the horizontal surfaces as well.

If you are fitting a gib strip, it should nearly fill the space available for it, and it should not have sharp edges fitting into the corners of the dovetail.

Neil

Edited By Stub Mandrel on 18/05/2013 11:11:36

Good choice of material, though good cast iron makes it a breeze.

Mill out the centre section square, then take progressive cuts the full depth with the cutter whose depth is the best fit. I normally do about three cuts, then take a final skim that is quite light (say 10 thou), if the starting slot is dead on size, aim to just remove any vertical witness with the final sizing cut.

Cut the dovetail which will be drilled for the gib screws first. The finish on this side is not critical as it doesn't slide on anything, so it makes an excellent opportunity for practice.

Another tip is to mill the dovetails before the outside surfaces are finished. The gib can be both adjusted in size and position to take up small errors, and then the outside surfaces skimmed to give neater joins than you would ever get by trying to get the dovetails exactly positioned.

If your mill is set up so you can take climb-milling cuts (where the mill is effectively pulling the work under the cutter) you may find a final, very light cut this way may give a better finish, but don't use the dovetail cutter to find out if your mill can do this. I suggest having a practice first anyway.

Neil

Hi All

Edited By John McNamara on 18/05/2013 12:58:58

Its the nature of forums Mark sometimes to move away from the original posters questions so do not get too confused.

Having made the central recess along the work piece with an end mill, therefore having vertical sides, lower the dovetail cutter into the recess by 4mm and start making the dovetail over part of the depth. Increase the width of the cut until there is just a very small flat left at the top corner.

Lower the cutter a further 4mm, to give the 8mm as per the drawing, and increasing the width of the cut until it just meets the portion already machined. From there, take a fine cut of around ten thou (using Neil's imperial dimension) and carefully machine the full width. Repeat if the result still needs widening to conform to the drawing.

Having gone for leaded steel you should have no problem if you take it steady, though of course we do not know the calibre of the machine you are working with.

Do take note of Neil's comments above re sharp corners, etc.

Harold

Do a search on Ebay for Woodruff cutters; ignore the over-priced buy-it-now ones, and see what is available on auction. That's how I got all my Woodruff cutters, and loads of side and face cutters and slab mills that cost an arm and a leg new. Standard small end mills I just buy new as needed.

Regards,

Andrew