Harrison Horizontal/Vertical Mill Restoration

[slim_boy_fat]

I'm taking the family up to Ullapool for a long weekend break

Have you seen the weather forecast for the weekend?

 

[slim_boy_fat]

"I indexed the second flat from the first using an engineers square against the flat and the edge of the milling vice jaws."

Or if, like me, you have difficulty seeing when something is at 180o to your original cut, one of these will come in handy [apologies for the pic size ]

 

[Carl Wilson]

I'd like to have some ER32 collet blocks, I shall have to invest in some in the future.

 

[slim_boy_fat]

I'd like to have some ER32 collet blocks, I shall have to invest in some in the future.

The Banggood ones are perfectly adequate.

 

[Dr.Al]

The Banggood ones are perfectly adequate.

The arceurotrade ones are good too, and they're cheaper than the banggood ones (especially if you've already got an ER nut)

 

[Carl Wilson]

I've noticed the bang good ones are more expensive. You can get ones on eBay that seem to me to be exactly the same as the bang good ones and they are nearly a tenner less.

I'm sure they are the same ones, right down to having the same description, verbatim.

I think the reason I haven't bought any thus far is that I had a vague idea that I would try to make some.

 

[fizzy]

Vertex are better quality than the cheapies.

 

[Shox Dr]

Vertex are better quality than the cheapies.

Vertex gear has gone through the roof price wise in the last few years.

 

[slim_boy_fat]

Well, there are these

https://www.banggood.com/ER32-MT2-M...-p-997701.html?rmmds=myorder&cur_warehouse=CN

https://www.banggood.com/Hard-Steel...e-Tool-Holder-p-1195642.html?cur_warehouse=CN

And age has caught up with me.... [although in my defence, I didn't say my latest one came from BG ] I got this one ex eBay, still from the Far East though.....

https://www.ebay.co.uk/itm/Hex-ER25...var=602212209586&_trksid=p2057872.m2749.l2649

 

[Carl Wilson]

Thanks chaps that has given me a choice of several.

 

[Carl Wilson]

I tested the arbor this evening and it worked well. It ran nicely true and the saw cut a uniform slit in a piece of bar that is orthogonal to the bar longitudinal axis.

I put my hand up to the fact that I was running the saw a bit fast; according to Chapman Part 2 (4th Edition) I should have been down at something in the region of 90rpm. Let's just say I wasn't...

I found it surprisingly difficult to find speeds and feeds for slitting saws on the net. To be honest I prefer information given in books. The Internet is a great resource for many subjects, including machining, but I find that a lot of what is out there is often conjecture as opposed to fact.

I should point out here that I'm aware that feeds and speeds are generally calculated for a production environment and a machine suited thereto. That said, they do give a starting point for experimentation.

Chapman is an excellent resource for anyone interested in machining. I've had both parts of this book since I was 17 and I still use them frequently.

 

[Carl Wilson]

My 10-24 UNC grub screws arrived today. So I'm now ready to make the special nuts. However, I'm about an hour and forty minutes away in the West Highlands.

Home Monday. These pictures have nothing to do with mill restorations. Just the views where I am.

And all the sweeter now it's no longer part of the EU.

 

[Carl Wilson]

Started making the special retaining nuts this morning.

Making from 30mm diameter EN1.

 

[Shox Dr]

Istr You tuber Abomb has a video with hand written calcs for slotting disc speeds.

If you think like its a cold cut saw, the slow speeds make sense

 

[Carl Wilson]

Yes. In the end I realised that it's just like a horizontal milling cutter. I got the feed rate recommendation from Chapman, that is to say 0.05 - 0.08mm per tooth.

For mild steel assume a cutting speed of 20 metres per minute.

So the saw is 2 3/4 inches which is 70mm. It has 72 teeth.

Speed in rpm = 1000 x s/pi x d

Where s = cutting speed in metres per minute and d = cutter diameter in mm.

Substituting the known values gives a figure of 90 rpm for the speed.

At 0.05mm feed per tooth, 72 teeth gives 3.6mm feed per rev. This gives 0.0036 x 90rpm = 0.3 metres/minute feed.

As I said before I get that this is open to some interpretation. It gives a good starting point. I'll run the saw as close to 90rpm as I can and just feed it slowly, so that it doesn't complain.

 

[Carl Wilson]

Continuing on with the special nuts. According to Machinery's Handbook the tapping drill for 3/8-24 UNF is 0.332". I used an 8.4mm.

When it comes to cutting the slot I'm going to take the chuck off the lathe and sit it on the mill table.

 

[Mark Davison]

My current project. This is a make shift short travel quill to enable me to use my vertical head as a drill without having to raise and lower the table all the time. ER20 straight shank collet chuck from banggood (£9 and surprisingly concentric). It will be operated by a lever and bearing carrier which will depress a spring loaded pushrod (where the draw bar would usually be) threaded into the end of the collet chuck. Styled on a schublin sensative drilling attachment.

 

[Carl Wilson]

Fantastic work Mark. Puts my paltry efforts to shame.

Did some more work on the special nuts this evening. Took the chuck off the lathe and set it up on the mill table. Then started cutting the slit in the first nut.

 

[Mark Davison]

Remind me, these are nuts for the change wheels on the table feed gearbox?

 

[Hopefuldave]

My current project. This is a make shift short travel quill to enable me to use my vertical head as a drill without having to raise and lower the table all the time. ER20 straight shank collet chuck from banggood (£9 and surprisingly concentric). It will be operated by a lever and bearing carrier which will depress a spring loaded pushrod (where the draw bar would usually be) threaded into the end of the collet chuck. Styled on a schublin sensative drilling attachment.View attachment 212089

View attachment 212088

That's sparked my interest, my mill's vertical head doesn't have a quill either - it has an ISO40 taper spindle, and I have a spare 20mm shrink-fit endmill holder I could open out to a sliding fit and a 20mm shaft ER32 collet chuck...

I'm guessing you're cutting a keyway in holder and collet chuck?
I *imagine* I'd have to use a hollow drawbar and a pushrod down the middle of it as I'd need to pull the 40 taper tight - any tips?

Dave H. (the other one) - PM me if you don't want to clutter this thread!