Member postings for Karl Hundermark

JasonB thanks for the recommendation on the inserts you suggested. They fit the holder and I no longer have the issue I initially had! Very sharp inserts, which cut brilliantly even on the titanium! No stress on the machine like a hot knife through butter on all the materials I’ve tried them on and a very good finish. Appreciate the assistance from everyone, issue resolved.

Regards,

Karl.

Thanks all, will keep this in mind!

Regards,

Karl

Sorry, took a while to go through and digest all that information. What I’ve gathered this far is as folllows:

1. Corner radius is important and should be 0.2mm ideally as opposed to the insert I have which is 0.4mm.

2. It should be a ground insert not a moulded one and that means it’s a lot sharper.

3. The type of the insert should be one that is capable of cutting titanium!

4. HSS do the job too, but are going to get worn down quicker.

I always have the fire extinguisher handy anyway and I didn’t realise titanium reacts to heat like steel with the colours!

So I’m going to try with a DCGT 070202 insert, If I needed to get another holder would it be specific to this type of insert?

Couple pictures of the holder below, can’t see any numbers on it anywhere. The holder is just over 9.5mm high too.

So I’ve taken a cut of 0.2mm each time with 3 different tools. The carbide insert, brazed carbide and HSS tools. The brazed carbide amd HSS took off the material exactly when measured with no strain on the lathe and the carbide insert took off only 1/2 of the cut as initially described in my original post with a bit of effort to cut. I’ve added a picture of each tool with the titanium and some swarf(if it helps!)

JasonB, I’m in the UK.

Regards,

Karl

First off, thanks to you all for your contributions, photos and links! Really insightful to a novice. Great community of members!

A bit of information regarding the actual carbide: it’s supplied by Sherline it’s their 55 degree carbide insert, it’s a gold colour(7605B this is the part number for it on their site which has the radius, angles etc) This is mounted in a Sherline RH 3/8” carbide insert tool holder and in turn is secured in a Sherline 3/8” toolpost. So all offered by the manufacturer for the machine, which made me assume it could be used within the limits of the machine and I had it purposed specifically for turning titanium and to save on sharpening HSS tools.

Hope the information on the bits gives a better idea.

Regards,

Karl

Hi all,

Thanks everyone for their input, it’s much appreciated!

I can now see the rigidity and shape of the tip definitely being an issue, it makes sense because when using the carbide tool it takes a fair bit of pressure when feeding it to cut. On the other hand with a newly sharpened HSS tool it it’s a very smooth and continuous cut with no strain on the machine even though it’s titanium. In terms of speed I’ve been calculating the rpm based on the sfm for the material and it’s diameter(there’s another number in there too that I can’t mind off the top of my head) which has worked well for all the other materials I’ve machines on it, even some stainless steel.

The main reason I was trying to use the carbide tool was the longevity of it, as much as I enjoy sharpening HSS tools I thought it would be more economical with my time to use carbide. As mentioned it may be the wrong type/shape?

I think I have a 1/4” brazed carbide tool floating about somewhere that’s as sharp as the HSS one, may be a better option than the insert type hopefully. Failing all that I’ll just need to stick to the HSS as Clive’s link shows.

Will let you know if I succeed!

Regards,

Karl

Hello all,

I’ve been having an issue with a 3/8” right hand carbide tool holder(carbide bit is held with one small torx screw) being used on a Sherline 4410 lathe.
I acquired the carbide tooling to assist in turning Titanium Grade 5 - TI6AL4V pivots, roughly 12mm diameter to required size. The lathe has a DRO which displays to 0.01mm on both axis(calibrated to the machine and compensated for backlash).
The issue is when using the carbide tool for example if the part is if I adjust the cross slide to remove 0.2mm depth of cut(0.4mm total material removed) it’s only removing approximately half of that amount I.e 0.1mm depth of cut, 0.2mm total material removed, the amount removed always seems to vary and is never a consistent error.

I’ve used a HSS 1/4” tool and there is no issue, my question is there something that I need to do different with the carbide tool? Thanks