MTFCA Forum

So I have been “commissioned” to copy my Tobin Arp thrust facing tool. It is a very nice design as you can move the cutting tool radially as it spins. The TA is 1-1/8” diameter boring bar.
Just wondering if any one else needs one.
I am contemplating making one also for myself that is on a 1” boring tool for my T line boring outfit
I know some people just face the cap in a lathe but I prefer having a full diameter thrust face

Pictures, please.

Les, I could be interested. I'd like to see your design. Would It be for a Tobin Arp TA 14 ?

Bill
Yes for a TA 14

Les, I would like to have one for my TA14. Count me in.

I know if you have to ask how much it cost you can't afford it, but I am going to ask anyway. Would it work with the KR Wilson boring bar?
When I had my block done it got the full face thrust also.

Bill and Eric
Thank you I will put you on the list

Cost
So far I am sourcing the components and talking to shops that can help with the project.
A project like this reminds me of the old joke;
“It’s a bit like buying hay, if you want top quality you need to pay a fair price, if the stuff that has been through the cow once is good enough, well that is considerably cheaper “!!

Les: Will parts be available? Will your parts work with an original? I have part of one. Thanks Dan

Dan
My plan is to make it functionally identical. The tool holder will be identical for sure as well as the controller.
I don’t want to disassemble the original one so I will guess a bit on the internal design.
I have finally succeeded in finding sources for the components and materials. Now to finalize the drawings!!

Hey all,
Forgive my ignorance. Kinda new to the repair end of a T. What is this tool used for?

Garland
The crank bearings of old engines are generally poured Babbit which is machined in place to fit the crank. One of the bearings (usually the rear one) controls the end float. This is a cutting tool for facing these surfaces.
I hope this helps

Got it. Thanks.

Here is one for sale:

https://www.ebay.com/itm/Tobin-Arp-faci ... Swd7RdN2EH

Dan
I saw that one last night. Unfortunately it is missing a part (which I see is advertised separately for $600.00), the “stability disc”(I will call it that)!
I have finally sourced the components that I can buy. Now to complete the drawings and start making the other bits. It appears that probably I should make twice as many tool holders and “stability discs”, as tool holders for sure get “lost “ over the years.
Right now it seems like 3 complete assemblies.
My target is about $1,000.00 each, but we will see!

The official name for the "stability disc is "Tool Holder Assembly" and the current part number was TA-950. The old part number for this was TA-B1130A.
As you probably know its serves two purposes- 1) a stabilizer for the facing tool and 2) a tool extension for large bores that were past the range of a long toolbit. With the tool mic at zero and on the extension, the tool would be set for a 4.125" bore or thereabouts. It seems odd, but my TA-14 manual has no mention of the Tool Holder Assembly or its use.